Biology Essay

BIOLOGY SPM ESSAY QUESTION COLLECTIONS

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Movement of Substances across the Plasma Membrane SBP 2011 1

(a)

Movement of substances across the plasma membrane in the cell is important for the continuity in life of organisms. The process helps to maintain a constant internal environment. (i)

Explain the importance of plasma membrane for the survival of living organism. ˗

˗ ˗ ˗ ˗ ˗ ˗ (ii)

[4 marks] living organism need nutrients / oxygen / glucose / mineral / any suitable example to continue their life`s processes ions inside cells must be kept at different concentration to outside the cells. to maintain a constant internal environment/ (homeostasis) The substances across the plasma membrane from the external environment cells produce waste products which exit through the plasma membrane The movement / types / amount of substances in and out of the cells is regulated by plasma membrane. the cells need to maintain suitable pH of the cells for enzyme activity so that cell can secretes useful substances / hormones / enzymes

Diagram 1.1 shows two types of transport of substances through plasma membrane.

Diagram 1.1 Explain the two types of transport of substances through plasma membrane shown in Diagram 1.1. [6 marks] Type 1 ˗ facilitated diffusion occur ˗ diffusion of small molecules / ions ˗ move from higher concentration to the higher concentration of solute ˗ through pore protein ˗ does no need energy


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Type 2 ˗ Active transport occur ˗ The molecules such as sodium ions / potassium ions / glucose / amino acid ˗ move against concentration gradient / from lower concentration to the higher concentration ˗ through carrier protein ˗ have active site with bind with particular molecule ˗ need energy / ATP (b)

A student carry out the experiment to determine the concentration of an external solution which is isotonic to the cell sap. The student immersed the potato strip in a different concentration of sugar in 30 minutes time. Diagram 1.2 shows graph plotted to show the change in mass against concentration of solution.

Diagram 1.2 (i)

Based on the graph in Diagram 1.2, state the concentration of the solution that is isotonic to cell sap. [1 mark] 2


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Isotonic to the sap cell: 0.27 mol dm-3/ 0.28 mol dm-3/ 0.29 mol dm-3 (ii)

Explain what happen to the cell at point P , Q and R. [9 marks] Point P ˗ The mass of potato increase ˗ (This occur because) the solution concentration is hypotonic to the sap cell of the potato ˗ The water molecule diffuse out from lower concentration/ hypotonic region to the higher concentration/ hypertonic region ˗ by osmosis ˗ cell becomes turgid (so the mass increased) Point Q ˗ The potato does not lose or gain mass ˗ This occur because the concentration o the solution is isotonic to the cell sap ˗ Diffusion of water molecule is at equilibrium / equal rate ˗ no net gain or loss of water molecule (so the mass is maintained) Point R ˗ The mass of potato decrease ˗ (This occur because) the solution is hypertonic to the cell sap ˗ The water molecule diffuse out from cells / from higher concentration to the lower concentration / solution at surrounding ˗ by osmosis ˗ cell becomes flaccid (so the mass decreased)

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Nutrition SBP 2011 1

(a)

Diagram 1.1 show the digestive system of a herbivore.

Diagram 1.1 Describe how cellulose in the plant fibres are digested and how the products of digestion of cellulose are absorbed into the body of the herbivore. [10 marks] How cellulose in the plant fibres are digested ˗ This is the digestive system of a non ruminant example a rabbit. ˗ Mouth: Plant tissues are cut, crushed and grind by the teeth / incisors / premolars / molars. ˗ Plant cell walls are disrupted / cellulose exposed ˗ Stomach / duodenum / ileum – No enzyme cellulase secreted / No digestion of cellulose. ˗ Caecum (Enlarged )/ contains microorganisms / bacteria / protozoa which secrete cellulase ˗ to digest the cellulose ˗ Appendix Enlarged / contains mi.croorganisms / bacteria / protozoa which secrete cellulase ˗ to digest the cellulose. ˗ Cellulase hydrolyse cellulose to glucose in the caecum and appendix Absorption of glucose ˗ Some glucose are absorbed by the caecum. ˗ No absorption of glucose in rectum ˗ Re-swallow the digested cellulose/glucose / pallet from the caecum after it has left the anus / coprophagy ˗ All the glucose is absorbed into the blood capillaries of the villus in the ileum

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BIOLOGY SPM ESSAY QUESTION COLLECTIONS (b)

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Diagram 1.2 shows a food pyramid.

Diagram 1.2 Based on Diagram 1.2, explain how a teenager may be able to plan his daily diet wisely to maintain his normal growth and good health. [10 marks] A good dietary habit for normal growth and good health of an adolescent: ˗ practicing a daily balance diet ˗ the diet comprises all food classes // carbohydrates, lipoids, proteins, vitamins, mineral salts and fibers // foods from level 1, level 2, level 3 and level 4. ˗ in the correct amount ˗ should take more foods from level 1, 2 and 3 / containing carbohydrates, fruits and vegetables / proteins ˗ for sustaining better general body growth / normal metabolism of the body. ˗ the adolescent requires more carbohydrates (as level 1) ˗ for example energy production / energy resources in the body ˗ More proteins (as level 3) ˗ for rapid muscular growth / replacement of dead tissues / cells / repairing damaged cells ˗ and synthesis of functional proteins/ enzymes / antibody /hormones / insulin ˗ vitamins / minerals serve as co-enzyme / co-factor for normal enzyme activities ˗ elements like Ca/ P / iodine are important for growth of bones / teeth / development of endocrine gland / thyroid ˗ fibers helps peristalsis in the alimentary canal / avoiding constipation ˗ should avoid from consuming excessive fats (as level 4) ˗ which is the principal cause of cardiovascular problems / heart problem / hypertension / thromboses coronary / arterosclerosis / obesity

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Kedah 2011 2

Diagram 2.1 shows a food pyramid.

Diagram 2.1 (a)

Explain why ice cream, butter cake are placed at level 4 in the food pyramid. [6 marks] ˗ ˗ ˗ ˗ ˗ ˗ ˗ ˗

(b)

Food at level 4 should only be taken in smallest amount / ratio. Ice cream contain a lot of sugar. Sugar has high energy value. Excessive sugar in the body will lead to obesity / diabetes. Butter cake contain a lot of lipid. Lipid has high energy value. Excessive lipid will form adipose tissue in the body // increase cholesterol level in body. (Excessive lipid will) lead to heart attack / cardiovascular disease / stroke.

Explain the importance of consuming food from level 2 in our daily diet. [4 marks] ˗ Food at level 2 contains a lot of water, vitamins, minerals and roughage / fibre. ˗ Water is important in all cell activities / physiological / biochemical processes in our body. ˗ Body need enough vitamins to preserve / maintain health // Any suitable example of vitamin and the related function ˗ Body need enough minerals to preserve / maintain health and growth // Any suitable example of mineral and the related function. ˗ Roughage is necessary in the diet to stimulate peristalsis / to prevent constipation.

(c)

Diagram 2.2 shows a few examples of fresh food and processed food.

Diagram 2.2


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Discuss the good effects and bad effects of processed food in our daily life. [10 marks] Good Effect : By producing processed food ˗ ˗ ˗ ˗ ˗ ˗

Food can be preserved / kept longer. to prevent food poisoning / wasting of food. Crops can be planted / livestock / poultry can be reared in big scale. to prevent food shortage. (food are packaged) to increase the commercial value / easier to be transported. more types / varieties of food can be produced.

Bad Effect : By regular consuming of processed food ˗ ˗ ˗ ˗ ˗

Loss a lot of nutrition value (under high temperature during the process). (Contain) preservative / colouring / dye / flavour which is carcinogenic. lead to mutation / cancer / health problem / suitable example. Contain excessive salt / sugar. lead to high blood pressure / diabetes / obesity

SBP 2010 3

(a)

Diagram 3.1 shows three processes involved before the food substances taken in areable to be incorporated into the body cells of humans.

Diagram 3.1 Explain the digestion of butter before it is absorbed by P. [4 marks] ˗ ˗ ˗ ˗ ˗ ˗ (b)

(Butter) contains lipids / fats Digestion occurs in the duodenum / ileum The bile salts emulsify the fats / turn into tiny droplets (Catalyses by enzyme) lipase By hydrolysis Fat into fatty acids and glycerol

Describe the absorption and assimilation of the food taken in during breakfast. [10 marks] Absorption 7


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˗ Products of digestion; glucose, amino acids, fatty acids and glycerols. ˗ Glucose and amino acids enters the blood capillaries of villi ˗ Fatty acids and glycerols enters lacteal of villi Assimilation (i) Glucose ˗ Used by cells to produce energy // Cellular respiration ˗ Excess glucose is converted into glycogen ˗ And stored in the liver / muscles ˗ (When liver is saturated with glycogen) glucose is converted into fats. (ii)

Amino acids ˗ Used to make proteins / enzymes / cell cytoplasm / muscle cells ˗ Used in growth / cell repairs ˗ Excess amino acids converted into urea ˗ And eliminate in the urine ˗ Excess may be converted into fats

(iii) Fats ˗ Used in building plasma membrane / cell membranes ˗ Excess fats are stored in adipose tissues (c)

About 50% of the small intestine of a man is cut and removed due to cancer. Explain the effect to the function of structure P and to the amount of stored carbohydrates in his organ Q. [6 marks] ˗ To the function of villi ˗ Less digested food is absorbed ˗ Because total surface area decrease / less ˗ Less digested food transported ˗ Because less blood capillaries / lacteals ˗ ˗ ˗ ˗ ˗

To the amount of glycogen in the liver Less glycogen (stored in the liver) No excess glucose Absorbed by villi Glucose absorbed (by villi) does not meet the body needs

Johor 2010 4

(a)

Photosynthesis occur in two stages which are light reaction and dark reaction. Describe the differences between the light reaction and dark reaction. [4 marks] Light reaction

Dark reaction

Occurs in granum

Occurs in stroma

Requires light

Does not require light Involves reduction/fixation of carbon dioxide Materials required is carbon dioxide / hydrogen atoms / ATP Produces glucose

Involves photolysis of water Materials required is water / chlorophyll Produces oxygen and water 8


(b)

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In countries with four seasons, plants are grown in greenhouse. Based on the statement, explain why this method is carried out to ensure the production of crops throughout the year. [6 marks] ˗ In the temperate countries light intensity / temperature changes throughout the year. ˗ In winter, temperature is very low. ˗ In autumn, the plants shed their leaves // Light intensity / temperature is low. ˗ Rate of photosynthesis is very low. ˗ In spring and summer, the light intensity / temperature are optimum for photosynthesis. ˗ So the rate of photosynthesis is maximum / highest. ˗ In the greenhouse, light intensity / concentration of carbon dioxide / temperature are maintained at optimum level (for photosynthesis) throughout the year. ˗ So the rate of photosynthesis is maintained at maximum level throughout the year (regardless of changes in light intensity or temperature). ˗ The plants are able to increase yields / increase the crops production throughout the years.

(c)

Graph in Diagram 4 shows the changes in the rate of photosynthesis throughout the day in a tropical country.

Diagram 4 Based on the graph, explain the changes in the rate of photosynthesis in the plant throughout the year. [10 marks] 0000 to 0600 ˗ The rate of photosynthesis is very low. ˗ The light intensity / temperature is (very) low. ˗ (At low temperature), photosynthetic enzymes are inactive. 0600 to 1200 ˗ The rate of photosynthesis increase (rapidly) ˗ Light intensity / Temperature also increases. ˗ Enzymes for photosynthesis become more active. ˗ Stomata open wider to allow absorption of more carbon dioxide. At 1200 ˗ The rate of photosynthesis is maximum / the highest. ˗ The light intensity maximum / temperature is optimum (for photosynthesis) / stomata open fully. ˗ Enzymes are the most active.


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1200 to 1800 ˗ The rate of photosynthesis decreases. ˗ Light intensity / temperature decreases. ˗ Photosynthetic enzymes are less active. ˗ Stomata openings / pores become smaller. ˗ Less carbon dioxide is absorbed. 1800 to 2300 ˗ The rate of photosynthesis becomes very low / stopped / ceased. ˗ Light intensity very low / temperature is very low / no light ˗ Photosynthetic enzymes are not active. ˗ Stomata closed. ˗ Very little / no carbon dioxide is absorbed. Perlis 2010 5

The photographs in Figure 5.1 show three individuals with different needs for energy.

Figure 5.1 (a)

(i)

What is a balanced diet? Why do we need a balanced diet? [2 marks] ˗ A balanced diet is the foods that contain correct proportion of nutrients which include carbohydrates, proteins, lipids, vitamins, minerals, water and dietary fibre / roughage. or ˗ A balanced diet is one which contains the correct proportions of all the different food requirement of the body. ˗ We need a balanced diet to supply enough energy for each day’s activities.

(ii)

Based on your biological knowledge about balanced diet, explain the factors that determine the energy requirement for the three individuals in figure 5.1. [8 marks] A lady athlete: ˗ An athlete is a very active person and has high rate of metabolism to produce energy. ˗ The diet should include more carbohydrates to supply enough energy to carry out the vigorous activity in sports // She needs to contract and relax her muscles frequently for her vigorous activities. // Energy is needed to contract the muscles. ˗ The diet should include more protein to build new tissues to replace tissues that are dead or damaged. 10


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˗ She also needs calcium, sodium and potassium to strengthen the bones and to prevent muscular cramp. A pregnant lady: ˗ A pregnant lady has a high rate of metabolism to provide energy for herself and the baby. ˗ The pregnant lady also needs more iron and calcium to build red blood cells to avoid anemia. ˗ She needs high quantity of calcium and phosphate to form strong teeth and bones for the baby. An old lady: ˗ An old lady has low rate of metabolism as she does not need energy to grow. (age) ˗ An old lady needs less carbohydrates and fats because she is less active and thus do not need much energy. ˗ She needs calcium and phosphorus to prevent osteoporosis. ˗ She should avoid food that contains a lot of fats, sugar and salt because excess fat can lead to heart diseases, excess sugar can cause diabetes mellitus and excess salt can cause high blood pressure. (b)

Figure 5.2 shows human’s digestive system. X is part of the cross section of structure Y.

Figure 5.2 (i)

What are the processes that occur in structure Y? Describe the processes by giving examples. [5 marks] ˗ Digestion // Intestinal glands of the wall of ileum secrete a few enzymes to complete the digestion process. ˗ Digestion process is complete in ileum to produce simple sugars (glucose, fructose and galactose), amino acids, fatty acids and glycerol. ˗ Example: 1. Enzyme erepsin (peptidase) – peptide to amino acids. 2. Enzyme sucrose – sucrose to glucose and fructose


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˗ Absorption // The wall of ileum has many projections called villus to absorb the products of digestion. ˗ Blood capillaries in the villus absorb simple sugars, amino acids, minerals, vitamins B and C (example) ˗ lacteal of the villus absorb fatty acids, glycerol, fat soluble vitamins A, D, E and K. (ii)

Describe the adaptations of X that allow structure Y to carry out its function efficiently. [5 marks] ˗ X is villus – has very thin epithelium that is only one cell thick. ˗ the thin epithelium facilitate the diffusion of digested food // enable digested food to move across easily. ˗ X is greatly folded structure. ˗ provides a large surface area for efficient absorption of digested food. ˗ It has a mass network of blood capillaries. ˗ to transport the digested food such as glucose, amino acids, minerals and vitamin B and C that has been absorbed. ˗ Each villus has a lacteal. ˗ to transport lipid soluble nutrient // fatty acids, glycerol and lipid soluble vitamins.

SPM 2006 6

Diagram 6 shows three organisms, P, Q and R.

P

Q

R

Diagram 6 (a)

(i)

Describe the type of nutrition in P and Q. [4 marks] P ˗ Autotroph ˗ synthesizes its own food ˗ from carbon dioxide and water using sunlight Q ˗ Heterotroph ˗ consumes food from organic substances in the environment

(ii)

Explain one similarity and four differences between the alimentary canal of Q and R. [10 marks] 12


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Similarity: ˗ The alimentary canals of both Q and R have bacteria / protozoa ˗ to hydrolyse cellulose Differences: ˗ R has 4 stomach chambers while Q has one stomach chamber. ˗ Where digestion of cellulose occur. ˗ The size of the caecum in R is small and short while in Q it is big and long. ˗ In Q, it is a place where bacteria hydrolyse cellulose. ˗ The bacteria and protozoa in R are found in the rumen and recticulum while in Q there are mostly found in the caecum. ˗ Bacteria secrete cellulase. ˗ In R, food passes through the stomach chamber twice while in Q food passes through stomach chamber once. ˗ To digest food by increasing the efficiency of the cellulase reaction. (b)

Constipation, night blindness and anemia are three health problems. State the cause and suggest the ways to overcome these health problems from nutritional aspects. [6 marks] Health Causes Ways to overcome problems Constipation

Insufficient amounts of fibrous food

Eat more vegetables and fruits

Night blindness Anaemia

Insufficient vitamin A Insufficient iron

Eat more carrots and tomatoes Eat more spinach

SPM 2008 7

(a)

(i)

After absorption of nutrients in the small intestine, the undigested substances in the colon result in the formation of faeces. Explain the formation of faeces in human. [4 marks] ˗ The contents in the small intestine that are not absorbed enter the colon. ˗ The intestinal content consists of a mixture of water, indigestible food, bacteria, dead cells and pigments. ˗ The contents move slowly along the colon by peristalsis. ˗ Water is reabsorbed and faeces are formed.

(ii)

Malnutrition is a condition due to taking an unbalanced diet in which certain nutrients are lacking, in excess or in the wrong proportions. Explain the effect on a child who is given insufficient amounts of any two nutrients of food for a long period of time. [6 marks] ˗ A child who is deficient in protein may suffer from kwashiorkor. ˗ Protein is need for normal growth. Lack of protein causes growth of the child to be stunned. ˗ A child who is deficient in vitamin C may suffer from scurvy. ˗ Vitamin C is need for healthy gums swollen and bleeding gums. ˗ A child who is deficient in roughage may suffer from constipation. ˗ Roughage is needed to stimulate peristalsis. ˗ Lack of roughage causes difficultly in defaecation. 13


(b)

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Table 7 shows the food intake by a boy aged 15 years in his daily menu. The daily energy requirement for him is 12 500 kJ. Types of food Quantity taken /g Energy content /kJ Rice

400

1 600

Potato chips

500

1 000

Chicken curry

300

300

Boiled egg

150

630

Butter

50

3 000

Milk

280

300

Sausage

300

500

Sardine

150 Table 8

900

(i)

Based on Table 7, state the value of energy contained in this daily food intake. Does the food intake satisfy his daily energy requirement? [2 marks] ˗ 8 230 kJ ˗ The energy produced from the food taken daily is insufficient.

(ii)

This boy takes this menu continuously for a long time. Explain the consequences to his health. [8 marks] The menu is an unbalanced diet because: Does not contain the 7 classes of food in the appropriate proportions

Leads to malnutrition

Does not contain sufficient roughage

Leads to constipation

Contains only certain vitamins

Leads to deficiency disease

Contains enough fat

Causes healthy life

Contains enough protein

Causes normal growth

Contains less minerals

Leads to deficiency disease

Adabi 2011 8

(a)

What is meant by a ‘balanced diet’? [2 marks] ˗ A balanced diet is a diet made up of all the seven classes of food in the right proportion for the body’s needs. ˗ The seven classes of food are carbohydrates, proteins, fats, minerals, vitamins, water and roughage.

(b)

Discuss the importance of the following classes of food: (i) roughage (ii) water

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Roughage: ˗ Provides the bulk to intestinal contents because of its high water holding capacity. ˗ Aids in peristalsis ˗ Aids in bowel movement ˗ Lowers the cholesterol level in the blood ˗ Deficiency of roughage can lead to constipation Water: ˗ Medium for all cellular biochemical reactions ˗ Medium for transportation for respiratory gases and nutrients ˗ Regulates body temperature ˗ Aids peristaltic temperature ˗ Maintain osmotic pressure in the tissue fluid and blood plasma (c)

Discuss a diet appropriate for the following target group: (i) children (ii) pregnant mothers Children: ˗ Appropriate food for children ˗ Children are in stage of growth. They need the food contain ˗ More carbohydrate, to provide extra energy for active children ˗ More protein to build body and tissues ˗ More fats, to provide energy and tissues ˗ More iodine mineral to produce thyroxine hormone essential for physical and mental growth ˗ More vitamin especially D for the absorption of calcium and phosphorus and folic acid to reduce the risk of birth defect ˗ High calcium and phosphorus content grow of bone and tissues Pregnant mother ˗ They need the food contain ˗ High protein such as meat (20% more than non-pregnant woman) for building foetus body tissues ˗ High carbohydrate content such as meat (14% more than non-pregnant woman) for building foetus body tissues ˗ High calcium and phosphorus content (50% more than non-pregnant woman) for building foetus body tissues ˗ Extra vitamins, especially D for the absorption of calcium and phosphorus and folic acid to reduce the risk of birth defect ˗ Extra irons for making red blood cells

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Respiration Kedah 2011 1

The diagram 1.1 shows two processes of energy production in human muscles.

Oxygen

Glucose

2898 kJ

Chemical equation:

C 6 H12 O 6  6O 2  6CO 2  6H 2 O  2898kJ glucose oxygen carbon water energy dioxide

Energy Process P

Glucose

Chemical equation:

C 6 H12 O 6  C 3 H 6 O 3  150kJ glucose lactic acid energy 150 kJ Energy (a)

Process Q Based on Diagram 1.1 , explain process P and process Q.

[4 marks]

Process P ˗ Aerobic respiration. ˗ glucose is completely oxidized / breakdown in the presence of oxygen ˗ the quantity of energy produced is higher Process Q ˗ Anaerobic respiration ˗ glucose is not completely oxidized / the glucose molecules breakdown partially (into lactic acid) ˗ the quantity of energy produced is lower (b)

Diagram 1.2 shows the respiratory centre and chemoreceptor which are involved in the regulation of the carbon dioxide content in the body.


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Diagram 1.2 Based on Diagram 1.2, explain how respiratory centre responses when the carbon dioxide content in the body increases during vigorous exercise. [6 marks] ˗ During vigorous exercise, carbon dioxide is produced and increased in the respiring cells. ˗ Higher concentration of carbon dioxide in blood results in decrease in blood pH / increase acidity. ˗ The drop in pH is detected by the central chemoreceptors (in the medulla oblongata ) ˗ The central chemoreceptors generate the nerve impulses ˗ The nerve impulse is sent to the respiratory centre ˗ The respiratory generate the new impulse. ˗ The impulses is sent to the diaphragm and the intercostal muscles ˗ Cause respiratory muscle to contract and relax faster ˗ As a result, the breathing rate increase (causes) ˗ More carbon dioxide is eliminated from the body, ˗ the carbon dioxide concentration of the blood return to normal level (c)

Diagram 1.3 shows the inhalation process in a fish. bucal cavity Gil Opercular cavity

Diagram 1.3 (i) Describe the breathing mechanisms in fish. [4 marks] ˗ ˗ ˗ ˗ ˗ ˗

When the mouth opens, the floor of the buccal cavity is lowered. Increase the volume/ space of the buccal cavity This lowers the pressure in buccal cavity . Water with dissolved oxygen is drawn into the mouth. When the mouth closes, the floor of buccal cavity is raised. Water flow through the lamellae and gaseous exchange between the blood capillaries and water takes place. ˗ Oxygen diffuses from the flowing water through the gill lamellae into the blood capillaries. ˗ Carbon dioxide diffuses from the blood capillaries via the gill lamellae into the flowing water.

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Diagram 1.4 shows the respiratory structure X and Y in the fish and human.

Diagram 1.4 (ii) Explain the similarities between respiratory structure X and Y in order to function efficiently. [6 marks] ˗ Both / fish and human have thin/one cell thick walls ˗ Gases can diffuse easily across the thin wall ˗ Human have a large number of alveolus while fish have a large number of filaments.// both structure X are exist in large numbers ˗ To increase surface area for exchange of gases ˗ Both structure X and Y/alveolus and gills are surrounded by a network of blood capillaries. ˗ To facilitate efficient exchange of and transport of respiratory gases / oxygen and carbon dioxide. Pahang 2010 2

(a)

Diagram 2 Diagram 2 (i) and (ii) show the respiratory structures of an insect. Describe the respiratory structure and breathing mechanism of an insect. [8 marks] Respiratory structure ˗ the tracheal system consists of network of trachea ˗ the trachea is lined with chitin to prevent from collapsing ˗ spiracle is tiny openings that allow air to go in and out ˗ the trachea branch into fine tubes called tracheole ˗ the tracheole branch throughout the body and penetrate into body tissues/muscle


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Breathing mechanism ˗ when the insect inhales, the abdominal muscles relax and spiracles open ˗ air pressure inside the trachea decreases and air is drawn in ˗ when the insect exhale, the abdominal muscles contract ˗ so increase air pressure inside trachea and forces air out through spiracles ˗ insect inhale and exhale through rhythmic contraction and expansion of their abdominal muscles ˗ the body movement and contractions of abdominal muscles speed up the rate of diffusion of gases from trachea into body cells (b)

Like animals, plants also respire aerobically to obtain energy for metabolism. They derive most their energy from cellular respiration. During cellular respiration, the plant cells take in oxygen and release carbon dioxide. Based on the above statement, describe the intake of oxygen by plants for respiration. [6 marks] Structure involved ˗ the intake occurs by diffusion mainly through stomata and lenticels ˗ stomata can be found in epidermis of the leaves /the stems of herbaceous plants ˗ lenticels can be found on the stems and roots of plants Explanation ˗ when stomata open, they connect the air spaces (within the leave) to atmosphere ˗ oxygen from atmosphere diffuses into the air spaces ˗ then dissolves in the film of water around the mesophyll cells ˗ so the concentration of oxygen in the cells becomes lower than in the air spaces ˗ thus, oxygen diffuse continuously from air spaces to the cell ˗ during daytime, carbon dioxide that is produced during respiration is used in photosynthesis ˗ the excess carbon dioxide diffuses into the air spaces and then through stomata into atmosphere

(c)

Diagram 2.2 Diagram 2.2 shows two types of different organelles. Explain the differences between the process that take place in organelle P and organelle Q. [6 marks] P: mitochondrion Q: chloroplast The differences between the process in organelle P and Q: Organelle P / Mitochondrion Organelle Q / Chloroplast Process

Respiration

Photosynthesis


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Aim

Release energy

Stores energy

Raw materials

Glucose, oxygen

Water, carbon dioxide, light

Products

Energy, water, carbon dioxide

Glucose / starch, water and oxygen

Energy

Not required

Required in form of light

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Dynamic Ecosystem Kedah 2011 1

Diagram 1.1 shows the distribution zones of mangrove trees K and L found in Kuala Kedah.

Diagram 1.1 (a)

(i)

Explain how mangrove trees K able to survive in zone U. [6 marks] ˗ ˗ ˗ ˗ ˗ ˗ ˗ ˗ ˗ ˗

(ii)

Mangroove trees K are Avicennia sp./ Sonneratia sp. have long underground cable roots that support them in the soft and muddy soil have thin, vertical breathing roots/ pneumatophores(which project above the water around the trees). gaseous exchange / breathing the root cells also have a higher osmotic pressure prevent water lost from cells ( in the sea water ) Salt water that enters the root cells is excreted through hydatodes (the pore in the epidermis of the leaves) Able to germinate while still being attach to the parent tree / vivipary which increase the chances of survival of the seedlings

Mangrove tree L is a successor of mangrove tree K. Explain how the process of succession occurs. [4 marks] ˗ Pneumatophore of pioneer sp / Avicennia sp / Sonneratia sp traps/ collect muds / organic substances/ sediments ˗ Increase the thickness of the soil / land become higher ˗ As time pass by the soil becomes more dense/ compact and firm/


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˗ drier ˗ The condition favours the growth of Rhizophora sp. ˗ The Rhizophora sp. replaces the pioneer species. 2

(a)

Panthera tigris (i)

(ii) Diagram 2.1

The classification of organisms is very important in ecological studies. Diagram 2.1 (i) and (ii) shows two different animals based on the above diagram, explain how a classification system is used to name both of these animals. [4 marks] ˗ based on Linnaeus Binomial system ˗ the first name begin with capital letter refers to genus whereas second name begins with small letter refers to species ˗ the names are written in italic ˗ (based on example from question) Panthera is the genus and tigris is the species (b)

(i)

(ii) Diagram 2.2

Name and describe the interactions shown in Diagram 2.2 (i) and (ii). [4 marks] Diagram 2.2 (i) ˗ Commensalism ˗ a clown fish gains protection from (predators) by living among sea anemones ˗ sea anemones unaffected Diagram 2.2 (ii) ˗ Mutualism ˗ alge synrthesis for itself and for fungus 22


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˗ fungus supplies carbon dioxide and nitrogenous compound for alga to synthesise its food

Diagram 2.3 (c)

Most microorganisms are harmless and useful to human being. Diagram 9.3 shows an example of a type of microorganism from the kingdom of Fungi. Describe the benefits of using above microorganism to produce useful products for humans. ˗ ˗ ˗ ˗ ˗ ˗ ˗ ˗ ˗

(d)

bread making flour, sugar and yeast are used. Yeast helps the dough to rise through fermentation that release carbon dioxide beer making – two species of yeast are used, beer is brewed from barley grains wine is made through fermentation of grape juices produce ethanol soya sauce is made from soya beans fermented by the action of fungi

It is important for us to conserve and preserve our biodiversity. Suggest three ways how to implement it. o [6 marks] ˗ Replanting programs after selective logging in rainforest ˗ Each house/school plant at least one tree ˗ Campaign through media/NGO/private sectors ˗ Banner/radio/television/pamphlet ˗ Recycle/reuse/reduce waste products ˗ Build the centre for recycling/any relevant explanation ˗ Stop open burning ˗ Dig and put the waste in the ground ˗ Car pool/use public transport ˗ Reduce the use of fuel and release of pollutants ˗ Any relevant fact ˗ Any relevant explanation

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Endangered Ecosystem Kedah 2011 1

(b)

Diagram 1.2 shows a section of a river that flows through rural and urban areas.

People live in residential area complained that the river water has turned green and many fishes die. Explain the phenomenon. [10 marks] ˗ Eutrophication occur ˗ Farmers use fertilizers that usually contains nitrates/phosphate ˗ Fertilizer/animal waste/silage which contain nitrate/phosphate may washed out in water when it rains/leaching/run into the river. ˗ Increase the nutrient content in the river ˗ Algae in the river grow faster (when they are supplied with extra nitrate/(phosphate)/ Algal bloom ˗ (they may grow so much) that they completely cover the water. ˗ block the sunlight to reach the plants in the water. ˗ Rate of photosynthesis decrease/ not occur ˗ The aquatic plants die ˗ Bacteria decomposed dead plant ˗ Population of bacteria increase ˗ oxygen in the water used up by the bacteria ˗ Dissolve oxygen also reduced/ BOD increase ˗ Caused aquatic plants and fish die

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Johor 2010 2

(a)

Diagram 2.1 shows a phenomenon which occur in the Earth’s atmostphere.

Diagram 2.1 (i)

Explain how the phenomenon happens and its effect on the environment. [6 marks] Causes of the phenomenon: ˗ This phenomenon is called green house effect ˗ Combustion of fossil fuels from vehicles / factories / forest burning / coal-fired power station ˗ excessive deforestation ˗ increase carbon dioxide concentration in the atmosphere cause by industries ˗ pollutants / CFC / methane Effects of the phenomenon ˗ carbon dioxide traps heat / infra-red light / long-wave radiation ˗ increase in global / world atmospheric temperature / cause a rise in Earth’s temperature / global warming ˗ melting of polar ice / rise in the sea levels

(ii)

Suggest measures needed to be taken to overcome the phenomenon. [4 marks] ˗ Use alternative source of energy to reduce the usage of fossil fuels / energy generated from wind / water / solar ˗ restrict open burning / forest burning / use incinerator ˗ reduce deforestation for farming / other development projects ˗ selective harvesting / logging / cut matured tree only ˗ replanting more trees which have been cut down ˗ the use of technology / unleaded petrol / catalytic converter

(b)

Diagram 2.2 shows another environmental phenomenon which has become a current topic of discussion. 25


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Diagram 2.2 Name this phenomenon and discuss the effects of the phenomenon on humans and ecosystem. [6 marks] ˗ The phenomenon is known as the thinning / depletion of the ozone layer ˗ More ultraviolet ray reaches the Earth’s surface ˗ Ultra-violet ray will deteriorate / weaken the human’s body immune system ˗ An increase in the number of people suffering from skin cancer / melanoma / cataract ˗ High ultraviolet rays destroy phytoplankton ˗ break the food chain of marine life / the aquatic ecosystem ˗ the number of stomata / chlorophyll of the leaves will be reduced ˗ Rate of photosynthesis decreases ˗ Changes in climate pattern (c)

Explain the concept of sustainable development and the need for it to protect our environment. [4 marks] ˗ (Sustainable development refers to) the measures undertaken to ensure that human activity optimally utilize Earth’s natural resources such that they can be replenished natural // suitable explanation ˗ Sustainable development is necessary as the rate at which man is using the finite natural resources will compromise future generation’s demands // suitable explanation/ necessary to exploit natural resources at the same time measures taken so that these resources can be replenished and be available for future generations. ˗ Ultimately, the natural resources, if continued to be depleted, will no longer be able to sustain human society // suitable explanation ˗ Sustainable development involves the protection of air / land / water / flora and fauna / forests ˗ which make up the surrounding we live in and survive upon. ˗ includes proper usage of renewable resources ˗ in order to maintain a stable / balanced ecosystem

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Kedah 2010 3

(a)

Diagram 3.1 shows the information relating to the campaign of recycling practice.

Diagram 3.1 Based on the given information, explain how recycle practice able to preserve the balance of environment. [10 marks] The tree ˗ Less tree will be chopped / felled ˗ More CO2 absorbed by the trees for photosynthesis ˗ Avoid the increasing of CO2 in the atmosphere. ˗ Reduce the impact of Green house effect // global warming ˗ Less habitat of fauna and flora will be destroyed. ˗ Reduce / avoid the extinction of fauna and flora. ˗ To maintain / preserve the biodiversity. The oil / fuel // Save Energy ˗ Reduce the burning of oil / fuel ˗ More fuel/energy can be preserved for future. ˗ Less green house gases / acidic gases released. ˗ Reduce / avoid the impact of green house effect / acid rain. The Landfill ˗ Less landfill will be opened ˗ Landfill cause leaching / ground water pollution. ˗ Less diseases / health problem caused by the improper managed landfill. The Water ˗ Less used water / effluent / untreated sewage released into river. ˗ Reduce / avoid the impact of water pollution / avoid the extinction of aquatic organisms. 27


(b)

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Diagram 3.2 shows a large area of forest involved in the building of a dam.

Diagram 3.2 Discuss the good and bad economical and environmental effects of this development. [10 marks] Good Effect ˗ Generate hydropower electricity ˗ As reservoir / to store water / supply fresh water ˗ Supply water for agricultural / industries. ˗ Place/site for recreation / tourism ˗ Reduce the flood problem at the downstream. Bad Effect ˗ Flooded / submerge trees / habitat of the fauna and flora ˗ Less tree / plants to carry out photosynthesis // Less CO2 absorbed for photosynthesis ˗ Amount of CO2 in the atmosphere increase ˗ Increase the impact of green house effect / global warming. ˗ Many species of fauna and flora extinct // Reduce the biodiversity. ˗ Reduce the flow of water at the downstream. ˗ Cause the population of aquatic life at the downstream reduce. ˗ Reduce the land used for residential / agricultural ˗ Flooded / destroy / loss of historical building / site.

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Melaka 4

(a)

A group of farmers planned to develop an agriculture nearby the lake. Besides to obtaining a high agriculture yield, they suggested that the area be made into a eco-tourism area. The following are a part of the details of their planning: Type of plants: Strawberry and rose plant. Location: Near a natural lake. Type of fertilisers used: Compost, lead nitrat salt, potassium nitrate, magnesium nitrate and phosphate. Based on the detail above, explain the effect on the lake if their planning is not managed properly. [10 marks] ˗ the leaching of chemical fertiliser/phosphate/nitrate from agriculture area to the lake ˗ Increase the fertility of the lake ˗ Encourages eutrophication (encourage algal growth) ˗ The growth alga prevent the light from reaching the base of the lake ˗ This reduce and prevents photosynthesis by aquatic plant. ˗ Reduse the oxygent release ˗ Aquatic plants and animals die due to lack oxygent. ˗ decomposition of dead plants, animals and organic mater by saprofitic bacteria iccure ˗ This will decrease the dissolved oxygen content ˗ BOD increase the water polluted ˗ This couse the aquatic animals die.

(b)

Diagram 4 shows one phenomenon in the ecosystem due to an unplanned development.

Diagram 4 Based on the Diagram 4, explain the phenomenon and its effect to the environment. [10 marks] ˗ (Name the effect) (The phenomenon) is acid rain ˗ Factors / motor vehicles / factory released large amount of nitrogen oxyde


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˗ ˗ ˗ ˗

and sulfur dioxyde oxyde of nitrogen combine with water vapour (in atmosphere) to form nitric acid. sulphur dioxyde combined with water vapour (in atmosphere) to form sulphuric acid. the rain fall as the acid rain.

˗ ˗ ˗ ˗ ˗ ˗ ˗

Effect may corrode the building acidic water couse aquatic animal died. minerals in soil dissolved/washed into river. siol become infertile / not suitable for plant to growth. Less yield / plant become die becouse the infertile soil. The ecological ballamce of ecosystem distrupt.

SBP 2010 5

(a)

Diagram 5.1 show a newly developed area.

Diagram 5.1 Explain how the human activity affects the river aquatic ecosystem. [10 marks] ˗ Water pollution ˗ Caused by abundant supply of fertilisers (that are discharged from the plantation into the river). ˗ Fertilisers contain high concentration of nitrates and phosphates ˗ Encourage eutrophication. ˗ They promote the rapid growth of algae // As a result, the population of algae increases. ˗ The surface of river is covered up by the algae (which grow extensively). ˗ The plants in the lower depths of the water cannot obtain sunlight. ˗ Hence, the plants die (when they are unable to carry out photosynthesis). ˗ The number of aerobic bacteria / decompose the dead plants also increases. ˗ They use more of the oxygen (in the water) during the decomposition. ˗ This reduces the concentration of oxygen in the water ˗ Causes the death of more aquatic organisms. ˗ The biochemical oxygen demand (BOD) increases (as a result of the rapid growth of the algae and the process of decomposition of the bacteria). (b)

Diagram 5.2 shows an environmental phenomenon. 30


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Diagram 5.2 (i)

Discuss the good and bad effects in the formation of a layer of greenhouse gases in the atmosphere. [5 marks] Good effect: ˗ Trap heat / provide temperature suitable to sustain life on earth. Bad effects: ˗ Increase global temperature // Greenhouse effect. ˗ Reduce agricultural productivity // Rate of photosynthesis. ˗ Change in global climate // Draught // Hurricane. ˗ Melting of ice caps in the artic. ˗ Rise in sea level // Big flooding // Sea water entering agricultural area. ˗ Death of plants / animals / humans // Reduce biodiversity.

(ii)

Can we save the world from the impact of the phenomenon? Justify your opinion. [5 marks] Opinion: Yes Suggestion: ˗ Avoid cutting down trees/ deforestation ˗ Plants absorb CO2 in the atmosphere ˗ Replanting ˗ To absorb CO2 by plants ˗ Avoid open burning ˗ To avoid the release of CO2 into the atmosphere ˗ Use public transport/LRT ˗ Less vehicles producing CO2 ˗ Use alternative energy from natural source (such as solar, wind, water flow) ˗ To decrease the release of CO2 by using fossil fuels as the energy source.

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Transport SBP 2011 1

(a)

Diagram 1.1 and 1.2 shows the stages in blood clotting.

Diagram 1.1

Diagram 1.2 Based on the diagram and on your biological knowledge, describe how the mechanism of blood clotting helps to prevent infection when a wound occurs. [10 marks] ˗ Wall of blood vessel is broken / damage / injured / severed ˗ The connective tissue in the vessel wall is exposed to blood. ˗ Platelets stick to the collagen fibres in the connective tissue. ˗ Then aggregation of platelets forms platelet plug. ˗ The clumped platelet, damaged cells and clotting factors in the plasma ˗ forms activators known as thromboplastine. ˗ Thromboplastine, in the presence of Ca2+ and vitamin K ˗ convert prothrombin ( inactive plasma protein) into thrombin (active plasma protein). ˗ Thrombin catalyses the conversion of soluble fibrinogen to insoluble fibrin. ˗ Fibrin threads form a network that mesh over the wound trapping red blood cells ˗ and sealing the wound. ˗ A blood clot is formed preventing further blood loss from the vessel. ˗ prevent bacteria / pathogen / microbe from entering the cell through wound (b)

The statement below describes the lymphatic system.  

Lacteals in interstinal villi transport products of lipids About 10% of interstitial fluid returns to the circulatory system via the lymphatic system.

Based on these statements, explain why the lymphatic system is considered complementary to the blood circulatory system.


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[10 marks] Statement 1: ˗ In the small intestine, the products of lipid which are fatty acids and glycerol ˗ are first transport into the lacteals in the villi. ˗ The lacteals fuse to form larger lymphatic vessels ˗ and enter the lymphatic system. ˗ Lymphatic fluid carrying the products of lipid digestion eventually drains into the thoracic duct. ˗ The thoracic duct merges into the left subclavian vein which is a part of the blood circulatory system. ˗ Thus the lymphatic system complements the circulatory system in transporting the products of digestion. Statement 2: ˗ (90% of) tissue fluid form at capillary network (interstitial fluid) ˗ must be return to the circulatory system. ˗ The remaining (10%) flows into blind-ended lymph capillaries ˗ which are found in capillary network. ˗ These lymph capillaries drain into larger lymph vessels ˗ which eventually drain back into the blood circulatory system ˗ via the thoracic duct and the right lymphatic duct. ˗ Thus, the lymphatic system complements the circulatory system in ensuring that the volume of blood in blood vessels is kept constant. SBP 2010 2 (a) Diagram 2.1 shows a body defense mechanism.

Diagram 2.1 Explain the body’s response towards the entry of bacteria into the body. ˗ ˗ ˗ ˗ ˗ ˗

[4 marks] Pathogens / bacteria succeed in penetrating the skin / first line of defence. Chemicals / proteins / antigens (produced by the pathogens) Attract the phagocytes / neutrophils / macrophages / monocytes (to the infected area) By using pseudopodia Surround / engulf / kill / destroy the pathogens / bacteria by lysozymes / lysosomes. 33

BIOLOGY SPM ESSAY QUESTION COLLECTIONS ˗ (b)

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A non-specific immune response.

Microorganisms are very useful in medicinal field. They are widely used in biotechnology in producing substances to fight against diseases. Explain this statement by using two examples of the application. [6 marks] Example 1 ˗ The production of insulin. ˗ Insert human gene (which controls the synthesis of insulin) into bacteria ˗ Bacteria are cultured / multiplied ˗ Insulin produced (by bacteria is collected) Example 2 ˗ The production of antiserum. ˗ (Specific) antigens / pathogens are injected into an animal. ˗ The animal produces (specific) antibody ˗ Antiserum is extracted / taken (from the animal’s blood). ˗ To stimulate passive immunity (in humans). Example 3 ˗ The production of vaccine. ˗ (A suspension) containing weakened / dead antigens / pathogen. ˗ Injected into human (body / blood) ˗ To stimulate the production of antibody (actively) // to achieve active immunity. Example 4 ˗ The production of antibiotics. ˗ Chemicals produced by microorganisms / Penicilium notatum / Streptomyces to kill other microorganisms / bacteria. ˗ Example: penicillin / streptomycin. ˗ Penicillin is used to treat gonorrhea / syphilis / lung infection. ˗ Streptomycin is used to treat tuberculosis / TB.

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BIOLOGY SPM ESSAY QUESTION COLLECTIONS (c)

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The graphs in Diagram 2.2 show the concentration of antibodies in the blood of two individuals, X and Y, after given two injections of different substances.

(i)

Diagram 2.2 Explain with examples why both individuals are immuned to specific antigens. [5 marks] ˗ Individual X is immune to (a disease such as) tuberculosis / TB / chicken pox / poliomyelitis / polio. ˗ Individual Y is immune to (a disease / toxin such as) tetanus / snake venom. ˗ Both involved in the increase in the level / concentration of antibodies (in the blood / body), ˗ Above the immunity level. ˗ The antibodies attack / neutralize specific antigens / pathogens in the body // The active sites on the antibodies are specific to certain antigens. ˗ Produce specific (immune) response.

(ii)

Describe the differences between the immunity obtained by the individuals. [5 marks] X

Y

Active immunity

Passive immunity

Immunity achieved through the injection of a vaccine

Immunity achieved through the injection of an antiserum / serum which contains a specific antibody

Does not result in an immediate immunity (against a disease)

result in an immediate immunity (against a disease)

Lymphocytes (in the body will be activated to) produce antibody

Antibody is received from the injections

The immunity usually last for a long time

The immunity lasts only for a short term / and offers temporary protection

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BIOLOGY SPM ESSAY QUESTION COLLECTIONS Second injection ( booster) is necessary to increase the antibody production (to a level that protects the person against the disease)

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Adabi 2011 3

(a)

Describe the role played by each of the following in maintaining the circulation of blood in the human body. (i) The heart (ii) The blood vessels (iii) The muscle of the limb [12 marks] Heart: ˗ The heart is a muscular organ with two distinct valves, the left side receives and pumps out oxygenated blood, the right side receives and pumps out oxygenated, the right side receives and pumps out deoxygenated blood ˗ Rhythmic contractions of the heart help pump blood into the pulmonary and systemic circulations ˗ The blood is pump into the systemic circulation at a lower pressure because the lungs are situated close to the heart ˗ The heart rate changes according to the body’s requirements ˗ Example, strenuous activity causes the heart rate to increase Blood vessel: ˗ Arteries are vessels that are thick-walled, containing muscle and elastic tissue within the walls ˗ Arteries are capable of peristaltic movement which pushes blood further along the arteries: this is important for arteries that supply tissues that are distant from the heart ˗ Veins are vessels with thinner walls and they have valves ˗ The pressure of blood in veins is very low, thus the presence of valves aid the flow of blood towards the heart ˗ Capillaries have wall which are one-cell thick and permeable. This allow the exchange of material between the blood and body cells. Muscle of the limb: ˗ Large veins are located between the muscles of limbs ˗ The constriction of muscles squeeze the veins ˗ Blood in the veins are forced to move in one direction only (towards the heart)

(b)

Diagram 3.1 shows a red blood cell structure. One of the major function of blood is the transport of oxygen.

Diagram 3.1 Describe how the structure of red blood cells is adapted to perform this function. [4 marks] 36

BIOLOGY SPM ESSAY QUESTION COLLECTIONS ˗ ˗ ˗ ˗

(c)

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The biconcave disc provides a large surface area to volume ratio This increases the rate of gaseous exchange The absence of a nucleus provides more space to store haemoglobin The flexible and elastic membrane of a red blood cell allows it to squeeze through narrow capillaries

Diagram 3.2 shows that the blood circulatory systems of an amphibian and a human.

Amphibian Diagram 3.2

Human

Based on the diagram compare both circulations. [4 marks] Similarities: ˗ Both are closed circulation systems ˗ Both are double circulatory system Differences: Amphibian Have three chambers in the heart

Human Have four chambers in the heart

There is some mixing of the oxygenated There is no mixing of the oxygenated and and deoxygenated blood in the ventricle deoxygenated blood in the ventricle (incomplete circulatory system) (complete circulatory system)


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TIMES 2011 4

(a) Diagram 4.1 shows the movement of water from the roots to the leaves and out to the atmosphere.

Diagram 4.1 Based on Diagram 6.1, describe the movement of water from roots to the leaves. [10 marks] Root pressure ˗ The cell sap of root hair (usually) hypertonic to the surrounding soil solution ˗ Water diffuses into the root by osmosis. ˗ (As they absorb more water by osmosis), a cell sap becomes more dilute compared to neighbouring cells. ˗ Water (therefore) moves to these adjacent cells which become more diluted themselves, so ˗ osmosis continues across the cortex ˗ (At the same time), ions from the soil are actively secreted into the xylem vessels and this causes osmotic pressure to increase ˗ Water flows continuously into the xylem and this create a pressure known as root pressure ˗ Root pressure gives an initial upward force to water and mineral ions in the xylem vessels Capillary action ˗ Water moves up through the xylem in the stems by capillarity (with is the upward movement of a ˗ fluid in a narrow bore tube) ˗ Capillary action is due to combined force of cohesion (water molecule have attraction for each ˗ other) and adhesion (water molecules are attracted to the side of the vessels) ˗ Water molecule form a continuous water column in the xylem vessel (due to cohesion and adhesion force enable water to move up along the xylem vessels) ˗ (As water is pulled upwards) the cohesion of water (which is due to hydrogen bonding holds the ˗ water molecule together) prevent the water column in the xylem breaking apart ˗ (At the same time) the adhesion of the water (to the wall of the xylem vessel and tracheids) prevents gravity from pulling the water down the column 38


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Transpirational pull ˗ The lost of water from the mesophyll cells during transpiration is replaces by water which flows ˗ in from the xylem vessels in the leaves ˗ This creates a tension / suction force in the water column because water has cohesive properties ˗ called transpiration pull ˗ The transpiration pull draws water from the xylem in the leaves/stems/roots. ˗ The continuous flow of water through the plant is known as the transpiration stream (b)

Diagram 4.2 shows part of the blood circulatory system and the lymphatic system in the human body.

Diagram 4.2 (i)

Explain the differences between the composition of fluid P and fluid Q. ˗ ˗ ˗ ˗

(ii)

[4 marks] Fluid Q/lymph has a larger numbers of lymphocyte compare to fluid P/blood lymphocyte is produced by the lymph nodes in lymph system Fluid Q/lymph has lower contents of oxygen compare to fluid P/blood oxygen has been used up by the cell

Describe how fluid Q is formed from blood until it is brought back into the blood circulatory system. [6 marks] ˗ (When the blood flows from arteries into capillaries)there is higher hydrostatic pressure at the arterial end of the capillaries ˗ (This high pressure) forces some plasma to pass through the capillary walls into the intercellular spaces (between the cells) ˗ Once the fluid leaves the capillary walls, it is called interstitial/tissue fluid // The interstitial fluid fills the spaces between the cells and constantly bathes the cells ˗ 90% of the interstitial fluid diffuses back into blood capillary ˗ 10% of the interstitial fluid that has not been reabsorbed into the bloodstream goes into the lymph capillaries. (Once inside the lymph capillaries) the fluid is known as lymph. ˗ The lymph capillaries unite to form larger lymphatic vessels. ˗ From the lymphatic vessels, lymph eventually passes into the thoracic duct/the right lymphatic duct. ˗ The thoracic duct empties its lymph into the right subclavian vein. (Hence, lymph drains back into the blood). 39


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Support and Locomotion SBP 2011 1

(a)

Diagram 1.1 shows the human vertebral coloumn. P and R are two types of vertebrae in the human vertebral column.

Diagram 1.1 (i)

Explain the adaptation of vertebrae P and vertebrae Q to function efficiently. [6 marks]

(ii)

˗ ˗ ˗ ˗ ˗

P is thoracic vertebrae Have long spinous processes and directed downwards for muscle / ligament attachment articulate with ribs to make up the side of the thoracic cavity.

˗ ˗ ˗ ˗ ˗ ˗

Q is lumbar vertebrae Largest / strongest vertebrae Their processes are short / thick Have large centrum which bear the weight of lower back To provide support to the (upper) body Are attach to many of the back muscles

Explain why human requires endoskeleton for efficient daily activities. [4 marks] ˗ ˗ ˗ ˗

Mechanical support Protection for internal organs A firm base the attachment of muscles Gives shape to the organism


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˗ Helps in movement of the organism ˗ Site for production of blood cells ˗ Storage for phosphate and calcium (b)

Explain why:  An athlete must do a warming up before the event  Elderly people experiences pain at their joint. [10 marks] An athlete must do a warming up before the event ˗ to increase temperature of body / muscle ˗ enabling more efficient use of energy ˗ more efficient of glucose oxidation ˗ increase blood circulation / increase heartbeat/supply oxygen faster ˗ prevent injuries to muscle ˗ muscle can contract more efficiently ˗ prevent muscle cramp / allow muscle to be stretch more easily Elderly people experiences pain at their joint ˗ small amount of synovial fluid produced (by the synovial membrane) ˗ thus increase friction between the end of the bones ˗ cartilage has become thinner ˗ thus cartilage is unable to cushions the joint / absorbs shock / further increases the friction between the end of bone ˗ ligaments become shorter / loss elasticity ˗ result in stiff / painful joint ˗ difficulty in movement

Kedah 2010 2

(a)

Diagram 2.1 show a fish.

Diagram 2.1 (i)

State two adaptations of the fish on how to reduce the resistance in water. [2 marks] ˗ fish have streamline shapes // the anterior of the fish is smooth and rounded // the body is long and tapers towards the end. ˗ the body of a fish is covered with scales that have a slimy coating

(ii)

Explain the role of body muscle in the mechanisms of locomotion in fish. [6 marks] ˗ ˗ ˗ ˗ ˗

myotomes muscles are arranged in both side of the body the vertebral column of the fish is flexible and can bent from side to side myotome muscles act antagonistically in fish./ carry out opposite action in a fish when the muscles on right side contract, the muscle on the left side relax the tail/body will be bent to the right. 41


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˗ when the muscles on left side contract, the muscle on the right side relax ˗ the tail/body will be bent to the left. ˗ alternate contraction of the right and left myotome block enable its tail to move left and right ˗ to produce a force that propel the fish forward. (b)

Diagram 2.2 shows a forearm of humans.

Diagram 2.2 (i)

Explain the similarity and difference between joint S and T. [8 marks] Similarities: ˗ Both Joint S and Joint T has a cavity filled with svnovial fluid // lined with synovial membrane ˗ Synovial fluid acts as lubricant to reduce friction between bones // absorbs shock of the movement. ˗ The end surfaces of the humerus bone of Joint S and Joint T are covered with cartilage ˗ To protect the bone / reduce friction between the bones ˗ Both Joint S and T are connected with ligaments ˗ to absorb shock // strengthen the articulation of bones/ joint. Differences: ˗ Joint S is hinge joint ˗ Joint S allows the movement of bones in one plane / direction ˗ Joint T is ball-and-socket joint. ˗ Joint T allows rotational movement of bones in all directions.

(ii)

Osteoporosis is a bone disorder. Arthritis cause painful joint. Explain the condition of osteoporosis and arthritis respectively. [4 marks] Osteoporosis ˗ the bone become thinner / more brittle / porous / fragile. ˗ Loss of bone mass. ˗ Lack of calcium / phosphorus / vitamin D Arthritis ˗ Cartilage between bones become thinner. ˗ Ligaments become shorter / loss elasticity ˗ Less production of synovial fluid. ˗ The joints become swollen / stiff / painful

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Coordination and Response TIMES 2011 1

(a)

Diagram 2.1 shows reflex arc when a hand touches a hot object while Diagram 2.2 shows synapse.

Diagram 2.1

Diagram 2.2

Based on Diagram 2.1 and 2.2, explain the pathway of an impulse in a reflex arc shown in Diagram 2.1. [8 marks] ˗ the heat on the object stimulates the nerve endings (receptors) in the skin. ˗ impulses are triggered. ˗ This impulses travel along the sensory/afferent neurone to the spinal cord. ˗ in the spinal cord, the impulses are transmitted first across a synapse to the interneurone and then across another synapse to the motor/efferent neurone. (at least 2 type of neurone) At synapse ˗ When an impulse reach a presynaptic membrane, it triggers the synaptic vesicles to release neutrotransmitter into the synaptic cleft. ˗ The neurotransmitter diffuse across the synaptic cleft ˗ and bind to receptors which are attached to the postsynaptic membrane. ˗ The binding of the neurotransmitter to the receptors leads to the generation of a new impulse ˗ Impulses leave the spinal cord along the motor/efferent neurone to the effector ˗ the effector is the biceps muscle which then contracts. This brings about a sudden withdrawal of the hand. (b)

(i)

Explain with the help of diagrams, how geotropism is brought about in a plant root and shoot. [8 marks] Diagram :

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Shoot ˗ The auxin that is produced at the tip of shoot. ˗ auxin moves downward/ accumulate on the underside of the shoot tip due to the pull of gravity. ˗ the high concentration of auxin accelerates the growth ˗ stimulating greater cell elongation on the underside relative to the cells on the upper side. ˗ this differential elongation causes the shoot to bend away from gravity / grow downwards. Root ˗ The auxin that is produced at the tip of root. ˗ auxin moves downward/ accumulate on the underside of the root tip due to the pull of gravity. ˗ the high concentration of auxin inhibits the growth ˗ slowing down cell elongation on the underside relative to the cells on the upper side. ˗ this differential elongation causes the shoot to bend towards gravity / grow downwards. (ii)

Explain the advantages of geotropism to a plant. [4 marks] Advantages

Explanation

Ensures the root grow/penetrate deep into soil The roots always contact with the soil water/mineral/nutrients The roots always contact with the soil water/mineral/nutrients

To anchor the plant firmly in the ground The roots always contact with the soil water/mineral/nutrients The roots always contact with the soil water/mineral/nutrients

Kedah 2010 2

(a)

Diagram 3.1 show the structure of a synapse.

Diagram 3.1 Explain how the nerve impulse is transmitted across the synapse. [6 marks] ˗ Nerve impulses arrive at the axon terminal of (presynaptic) neurone. ˗ Causes the synaptic vesicles to move towards the (presynaptic) membrane and fuse with the membrane. 44


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˗ Neurotransmiters /acetylcoline (examples) molecules are released from synaptic vesicles. ˗ (The neurotransmitter molecules) diffuse across the synaptic cleft into the postsynaptic knob / dendrite / cell body of neighbouring neurone.. ˗ The neurotransmitter molecules bind to specific receptor sites in the postsynaptic knob. ˗ The binding triggers / generates new nerve Impulses. ˗ The impulses then move along the postsynaptic neurone. ˗ The release of neurotransmitter is in one direction, from the synaptic knob to the postsynaptic neurone. ˗ Mitochondria in the synaptic knob generate ATP / energy to synthesis neurotransmitter molecules. (b)

Diagram 3.2 shows a reflex action that involves neurone X and Y.

Describe the reflex action. [4 marks] The receptor at the terminal of X stimulated by the heat. The receptor generates a nerve impulse. The nerve impulse travels along X / afferent neurone to the spinal cord. In the spinal cord, the nerve impulse is transmitted to an interneurone. From the interneurone, the nerve impulse is transmitted to an efferent neurone/ neurone Y. ˗ Nerve impulse travels along efferent neurone / Y and reach the effector / muscle tissue / fingers. ˗ Muscles contract to withdraw the hand / finger. ˗ ˗ ˗ ˗ ˗

(c)

When a man is chased by a fierce dog, he is experiencing ‘fight or flight’ situation. Explain how the nervous system and the endocrine system of the man coordinate to respond to his situation. [10 marks] ˗ The receptors in the eyes detect the dog. ˗ Nerve impulses are generated and transmitted to the brain via the afferent neurone. ˗ The hypothalamus in the brain is stimulated. ˗ It actives the sympathetic nervous system to generate nerve impulses. ˗ Nerve impulses are transmitted to the adrenal medulla to stimulate secretion of adrenaline. ˗ Adrenaline carried / transported by blood circulatory system to the targeted organs. ˗ Adrenaline promotes the breakdown of glycogen to glucose. ˗ (Adrenaline) increases the breathing rate. ˗ More oxygen will be taken into the body ˗ (Adrenaline) increases the rate of heartbeat/ blood pressure. ˗ Rate of the blood flow increase. ˗ More glucose and oxygen will be supplied to the muscles. ˗ More energy produced by the muscles. // metabolic rate increase. ˗ Body has enough energy to face the ‘fight or flight’ situation. 45


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Melaka 2010 3

(a)

(i)

Diagram 3.1 shows the formation of glomerular filtrate in process Y during urine formation.

Diagram 3.1 Based on Diagram 3.1, describe briefly the formation of the glomerular filtrate. [4 marks] Process Y is ultrafiltration A process whereby ˗ water and solutes from glomerulus being forced to filter through the membrane of Bowman’s capsule ˗ by the high hydrostatic pressure ˗ forming glomerular filtrate that contains water, glucose, amino acids, urea, mineral salts and other small molecules (b)

En. Kamal was informed by his doctor that his left kidney fail to function. By using your biology knowledge, explain the effect of his kidney failure on his health and give a suggestion to overcome this problem. [6 marks] ˗ less efficient in filtration of waste products and excess water in blood plasma ˗ as a result, urea uric acid/ creatinine / salt concentration will be increase ˗ increase the blood pressure ˗ use haemodialysis machine / kidney transplant ˗ to replace the function of kidney; filtrate all the waste product and excess water.

(c)

Table 3.2 shows the concentration of solutes in the blood plasma, glomorular filtration and urine of an adult. Concentration of solutes (g/dm3) Solute Blood plasma Glomerular filtrate Urine Glucose

1.0

1.0

0.0

Amino acid

1.5

1.5

0.0

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Protein

80.0

0.0

0.0

Urea

0.3

0.3

20.0

Sodium ion, Na+

3.2

3.2

1.6

Table 4.2 Base on the Table 3.2, explain why the concentration of solutes in the plasma, glomerular filtration and urine of the adult are differ. [10 marks] ˗ Glucose reabsorbed by facilitated diffusion into blood capillary ˗ Glucose needed by our body ˗ Acid amino reabsorbed by facilated diffusion ˗ Acid amino is needed for body growth / tissue repair ˗ Protein is a big molecule and cannot move via membrane plasma. ˗ Protein is still circulate in blood capillary. ˗ Urea is secreted substances and cannot move back to blood capillary ˗ Water is reabsorb by osmosis and the concentrate of urea increase. ˗ Sodium ion is move back to blood capillary via active transport ˗ Sodium is importance for maintain the blood pressure. Pahang 2010 4

(a)

Diagram 4.1 Diagram 5.1 shows the negative feedback mechanism that regulated the blood glucose level in human being. (i) Explain briefly the meaning of ‘negative feedback’ in Diagram 4.1. [2 marks] ˗ it is a corrective mechanism (which reverses the original change and brings the system back to normal) ˗ when the blood glucose level decreases, it will increase and finally back to normal// vice versa (ii)

Describe how hormone X and Y regulate the blood glucose level in humans. [8 marks] ˗ Hormone X and Y are produced by pancreas 47


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˗ Hormone X/glucagon is secreted by alpha cells whereas hormone Y/insulin is secreted by beta cells ˗ if the blood sugar level is lower than normal, more hormonebX/glucagon is secreted into blood stream ˗ hormone X/glucagon is transported by the blood to the liver ˗ hormone X/glucagon causes/stimulates the liver to breakdown glycogen to glucose ˗ this causes the level of glucose to rise and back to normal ˗ if the blood sugar level is higher than normal, more hormone Y/insulin is secreted ˗ hormone Y/insulin causes/stimulates the liver to convert glucose into glycogen ˗ this causes the level of glucose decrease and back to normal (b)

(i)

Diagram 5.2 Diagram 4.2 shows the various structures involved in regulation of body temperature in the human body. A worker enters a cold room that stores frozen meat. Explain how the regulation of the worker’s body temperature occurs. [6 marks] ˗ when the environment is too cold, the stimuli is detected by receptors in the skin ˗ impulse is sent to brain/hypothalamus ˗ hypothalamus send impulse to the effectors ˗ sweat glands are not stimulated so no sweating ˗ vasoconstriction of arterioles in the skin, less blood flows to the skin ˗ so less heat is lost (to surrounding) ˗ erector muscle contracts, hair raise up so trap more heat ˗ adrenal gland secrete adrenaline whereas thyroid gland secretes thyroxin to increase metabolic rate ˗ shivering takes place, this results in increased the production of heat (ii)

Plants, like animals must respond to conditions and changes in the environment in order to survive. In plant, response is controlled by chemicals called plants hormone or plant growth regulators. A plant hormone is a chemical substance which is produced by a plant and influences the growth and development of the plant. Based on the statement above, state and explain the use of hormones in agricultural. [4 marks] Auxin ˗ promote the growth of adventitious root ˗ induce the development of fruit without ˗ fertilization/parthenocapy/fruit without seed


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˗ prevent young developing fruit from falling off prematurely ˗ gardeners use auxins to stimulate growth of fruits/to delay fruit ripening Ethylene ˗ promoting the ripening of fruits // the unripe imported fruit will be exposed to ethylene gas for sale Johor 2010 5

(a) Describe how the structure of the kidney are adapted to enable them to play a role in homeostasis. [4 marks] ˗ (each kidney) contains hundreds of thousand / a large number of nephrones / nearly one million nephrones ˗ to filter substances from the blood efficiently ˗ (each kidney) has ureter ˗ to carry away the urine / solution of wastes dissolved in water / creatinine / toxin and drugs ˗ (each kidney) has rich capillary network ˗ ultrafiltration / reabsorption can take place efficiently ˗ Has Bowman’s capsule / proximal convoluted tubule / loop of Henle / distal convoluted tubule / collecting duct ˗ ultrafiltration / reabsorption / secretion (b)

Diagram 5 shows a simplified version of a kidney dialysis machine.

Diagram 5 Describe how the machine is used to remove waste products such as urea from a person with kidney failure. [6 marks] ˗ blood from the patient’s vein is passed through a machine ˗ which contains a dialyser / dialysis solution ˗ dialysis tubing has a semi-permeable membrane ˗ concentration of waste molecules / urea in blood is higher than in the dialysis solution // there is concentration gradient between the blood and dialysis solution 49


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˗ waste molecules / urea / excess salts diffuse through membrane from blood to dialysis solution ˗ dialysis solution is continuously being replaced // essential substances remain in the blood ˗ plasma protein / red blood cells are not able to diffuse through membrane of dialysis tubing ˗ because the size is bigger / too big ˗ the direction of the flow of blood is opposite to the direction of dialysis solution ˗ to ensure the waste molecule / urea is continuously being remove from blood to dialysis solution ˗ the filtered blood re-enters the patient’s blood vessel / vein (c)

Table 5 shows the composition of human blood and urine. Chemical substances

Percentage in blood, %

Percentage in urine, %

Water

97

95

Plasma protein

8

0

Glucose

0.10

0

Urea

0.03 Table 5

2.0

Explain the differences between the percentages of chemical substances in blood and urine. [10 marks] ˗ percentage of water in blood is higher than in urine ˗ in the proximal convoluted tubule ˗ the Na+ are pumped into the capillary // some salts are reabsorbed by active transport ˗ the movement of solutes into the capillary network decreases the solute concentration of the filtrate but increases the solute concentration in the capillary network ˗ as a result, water diffuses into blood capillaries by osmosis from the proximal convoluted tubule / Loop of Henle / distal convoluted tubule / collecting duct ˗ percentage of plasma protein is higher in blood compared to urine // percentage of plasma protein is nil in urine ˗ size of plasma proteins are larger / too large which cannot be filtered out / diffused out during ultrafiltration ˗ percentage of glucose is higher in blood but nil in urine ˗ all glucose are reabsorbed by active transport at proximal convoluted tubule ˗ percentage of urea is higher in urine than in blood ˗ urea is actively transported from the blood capillary to the distal convoluted tubule ˗ by active secretion process ˗ urea is filter but not reabsorbed into the blood ˗ selective reabsorption

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Reproduction and Growth Kedah 2011 1

Diagram 1.1 shows menstrual cycle which is controlled by certain hormones produced by pituitary and ovary.

Diagram 1.1 (a)

Explain the changes and the functions of each type of hormone produced by pituitary and ovary. [8 marks] FSH (Follicle – stimulating hormone) ˗ From day 1 to day 5, pituitary gland stars to secrete FSH ˗ FSH stimulates the development of follicle ˗ And stimulates the tissue of ovary to secrete oestrogen Oestrogen ˗ From day 5 to day 13, concentration of oestrogen continue to increase ˗ Oestrogen causes the repair and heal of the endometrium lining ˗ Endometrium lining becomes thicker and ( filled with blood vessels) LH (Luteinising Hormone) ˗ On day 13, the LH level increases ˗ Causing ovulation / Graafian follicle releases secondary oocyte. ˗ LH causes the formation of corpus luteum ˗ Corpus luteum secretes progesterone Progesterone ˗ Progesterone maintains the thickening of endometrium for implantation


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˗ Progesterone inhibits the secretion of FSH and LH ˗ If the secondary oocyte is not fertilised by a sperm, corpus luteum disintegrate / progesterone decreases ˗ Endometrium lining begins to breakdown and menstruation starts (b)

Diagram 1.2 shows the growing of pollen tube in the style and the process of double fertilisation in flowering plant.

Diagram 1.2 (i)

Describe the growing process of pollen tube in the style and and the process of double fertilisation in flowering plant. [7 marks] Growing of pollen tube process ˗ Sugary/sucrose solution stimulate the growing of pollen tube ˗ pollen tube grows down the style towards the ovule ˗ The generative nucleus divides to form two male gametes nuclei ˗ Leading the front is the nucleus tube Double fertilization ˗ Pollen tube penetrate the micropyle to reach the egg cell ˗ Nucleus tube disintegrate ˗ one of male nucleus fuses with egg cell to form a diploid zygote ˗ other male gamete nucleus fuses with the two polar nuclei forming a triploid nucleus. ˗ which later develops into the endosperm ˗ the synergid cells and the antipodal cells disintegrate


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Diagram 1.3 shows the stages of secondary growth in a dicotyledonous stem.

Diagram 1.3 (ii)

Explain the process of secondary growth in dicotyledonous stem. [5 marks] Secondary growth of dicotyledonous stem ˗ Secondary growth of dicotyledonous stem involves vascular cambium and cork cambium ˗ Vascular cambium divides actively by mitosis. ˗ To form ring of cambium / new cells ˗ Cells at inner layer will form secondary xylem ˗ Cells from outer layer will form secondary phloem ˗ Cork cambium divides by mitosis to form new cells ˗ The new cells at the inner layer form parenchyma ˗ The new cells at the outer layer form cork (tissue)

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BIOLOGY SPM ESSAY QUESTION COLLECTIONS 2

(a)

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Diagram 2 shows the level of four hormones and the sequence of events that occur during a menstrual cycle of a healthy woman.

Diagram 2 Describe how the menstrual cycle is affected if the pituitary hormones peak up seven days later. [10 marks] ˗ Menstruation / menses will occur a week later (than usual) // on the 7th day of the following cycle / month. ˗ FSH peaks up on day-20 / a week later / just before day-21. ˗ LH peaks up on day 20 / a week later / just before day-21. ˗ ovulation only occur a week later / day-21 ˗ due to stimulation / from a rise of LH ˗ level of estrogen remains high until day-21 because ˗ graafian follicle that release estrogen remains intact / due to no LH ˗ corpus luteum will only be formed on day-21 / a week later ˗ this causes level of progesterone to increase after day 21 and remains high ˗ as level of progesterone high, the lining of uterine wall / endometrium will remains thick longer ˗ when corpus luteum degenerate, level of progesterone drops ˗ this causes the lining of endometrium to disintegrate causing menses which occurs a week later than usual (b)

“In Malaysia, it is estimated that one baby is abandoned every 10 days in the Klang Valley, and 100 babies abandoned every year nationwide.” The Star Online, September 27, 2008


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Discuss the advantages and the disadvantages in the application of science and technology in human reproduction in handling the issue. [10 marks] Advantages: ˗ Sterilise method; vasectomy / by cutting the vas deferens in testes ˗ to prevent the sperms from going to prostate glands// ejaculation does not contain sperms ˗ use of (male) condoms ˗ prevent / reduce chances of sperms from going into cervix / uterus ˗ Use female diaphragm that covers the cervix // Use of female condom which is fitted inside vagina ˗ Block entrance of sperms into the uterus // Prevent entrance of sperms into uterus // sexually transmitted disease ˗ Contraceptive pills // Contraceptive implant// Depo-vera injection ˗ prevent development of follicle // inhibit ovulation // difficulties in implantation of zygote ˗ Morning after pill ˗ Prevent fertilization ˗ Sterilization by cutting and tying the fallopian tube ˗ Prevent the egg travelling along the fallopian tube / sperms reaching the ovum. Disadvantages: ˗ Sterilising method cause permanent disabilities to produce sperm / ovum hence the person is not able to produce off springs anymore ˗ Condoms; sometimes sperms can still penetrate therefore chances of getting pregnant is still there ˗ Pills are unreliable because they have to be taken consistently ˗ All these methods will cause teenages / unmarried adults to increase their sexual activities (because they are not afraid to get pregnant thus increasing the moral issues in the societies). 3

Sexual reproduction in plants involves the production of pollen grains and ovules. (a)

By using a flow chart describe how pollen grains are formed in plants. [10 marks]

˗ ˗

Pollen grains are male gametes (produced in the anther/pollen sac (pollen sac) contains diploid pollen parental cell/ pollen mother cell/ microspore mother cell

BIOLOGY SPM ESSAY QUESTION COLLECTIONS ˗ ˗ ˗ ˗ ˗

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(each pollen mother cell) undergoes meiosis Producing 4 haploid microspores(n) nucleus of (every) microspore undergoes mitosis forming two nuclei The generative nucleus and the tube nucleus Microspore with surfaces adapted for dispersion and is now called pollen

Reproduction technology has contributed a lot to human health and population growth. (b)

Describe how infertility is overcome in humans using the following methods:  Sperm banking  Artificial insemination  In vitro fertilization  Surrogate mother [10 marks] Sperm bank ˗ Used when the man/spouse/male suffers from low sperm count/production of weak/unhealthy sperms ˗ Sperms are donated and donor’s identity is recorded/secret ˗ Genetic biodata of donor and the woman recipient should match for successful fertilization Artificial insemination ˗ Practiced by a couple when the man is sterile ˗ Donor’s sperm are injected into the womans uterus during ovulation ˗ No sexual intercourse is involved ˗ The genetic background and health of donor is screened before acceptance In vitro fertilization ˗ Practiced when the woman’s ovum cannot be fertilized due to blockage of fallopian tube ˗ Ovum is extracted (from the woman) and fertilized outside the body/in Petri dish/test tube ˗ Fertilized ovum/zygote grows in culture medium ˗ Than it is implanted into the woman’s uterus Surrogate mother ˗ Method practiced when a woman cannot be pregnant in normal way ˗ The zygote is obtained by invitro fertilization ˗ Another woman is implanted with the couple zygote ˗ (Surrogate mother) carries the baby only until it is born

4

Length (cm)

Height (cm)

Time (year) Graph 4.1 (a)

Time (day) Graph 4.1 (b)

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BIOLOGY SPM ESSAY QUESTION COLLECTIONS (a)

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Graphs 4.1 (a) and 4.1 (b) show the growth curve of human and insect. Based on the graphs, compare the growth process in human and insect. [10 marks] Similarities - height of man / length of instar increases by time - both show horizontal line / constant growth during adult Difference - Form of graph – Sigmoid form for human and like series of steps in insect - Age of organism – the height measured yearly, but in insect used day for measuring the length - Caused of different – human have endoskeleton but insect have exoskeleton - Stages involve – in human, the curve has three different phases, but there are five steps in insect // nymphal stages - Vertical and horizontal line : curve for human did not shows different line (only the curve from continuous points), but there are five different horizontal and vertical lines each - Zero growth – no point to show zero growth in human, but there are 5 time of zero growth (at horizontal line) - Sudden growth : no sudden growth for human, but there are sudden growth in insect (at vertical line) - Ecdysis : no ecdysis in human but ecdysis occurred in insect - Mitosis : the cells in human undergo mitosis all the time, but in insect, mitosis only occurred at certain time (during ecdysis) - Absorption of air : in human, there are no absorption of air, but in insect, during ecdysis

(b)

A couple, Mr Zafrie and Mrs Munirah had married almost ten years but still do not have any child. After undergone an inspection, they found that the husband does not have any problem but the Fallopian tube of Mrs Munirah is blocked. Based on your biological knowledge in reproduction technology, explain how the couple can have children. [10 marks] In-vitro technique ˗ means fertilization occurs outside of the body ˗ the wife injected with hormone to fasten the development of the secondary oocyte / ovum in ovary ˗ secondary oocyte / ovum release out by using laparoscope (from ovary before ovulation) ˗ sperms from husband fertilize with the secondary oocyte in a Petri dish (contains culture medium) ˗ (after fertilization) zygote will divide by mitosis ˗ (after 2 days) formed embryo until eight cells stage ˗ embryo transferred to the endometrium of the uterus wall through cervix (using pippet) ˗ embryo implant at the endometrium of uterus wall and develop ˗ baby that is delivered is called test tube baby ˗ This technique is complicated / expensive and the probability to success is low

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BIOLOGY SPM ESSAY QUESTION COLLECTIONS 3

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(a)

(i)

(ii) Diagram 3.1 Diagram 3.1 (i) and (ii) shows the formation of pollen grains and development of the embryo sac. Describe both processes. [8 marks] Pollen grains ˗ pollen is produced in the anther (which consists of four pollen sacs) ˗ each pollen sac contains hundreds of pollen mother cells which is diploid ˗ each mother cells undergoes meiosis to form four haploid microspores/cells/tetrad ˗ each cell /tetrad develop into pollen ˗ the nucleus of each cell/microspore/tetrad undergoes mitosis to form (pollen) tube nucleus and generative nucleus Embryo sac ˗ embryo sac mother cell (diplod/2n) undergoes meiosis to form four haploid cells/megaspores ˗ three of the cells/megaspores degenerate, leaving only one(in the ovule) ˗ nucleus of megaspore undergoes mitosis three times to form eight haploid nuclei ˗ three of eight nuclei migrate to one end of the cell to form antipodal cells ˗ another two nuclei/polar nuclei move to the centre ˗ near the opening of ovule/micropyle) one of three nuclei develops into egg cell/female gamete flanked by two synergid cells ˗ the structure formed is known as embryo sac


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(b)

Diagram 3.2 Diagram 3.2 shows the process of double fertilization in plant. Describe the process and explain the importance of double fertilization for the survival of flowering plants. [6 marks] ˗ The process of double fertilization ˗ a pollen grain on stigma initiates the fertilization process ˗ sugar (solution) in the stigma stimulates the pollen to germinate and form a pollen tube ˗ the pollen tube grows down the style towards the ovule ˗ (during the growth of pollen tube) the generative nucleus divides by mitosis and form two male gamete nuclei ˗ the male nuclei follow the tube nucleus down the pollen tube ˗ pollen tube reaches ovule through micropyle and tube nucleus disintergrates ˗ one male gamete nucleus fuses with egg nucleus forming diploid zygote(2n) ˗ other male gamete nucleus fuses with the two polar nuclei forming a triploid nucleus(3n) ˗ ˗ ˗ ˗ ˗

(c)

Explaination genetic information of parents plants is passed down to the next generation (diploid zygote) variation in next generation (as a result of the formation of the male gamete fuses with egg cell) endosperm provides food for developing embryo during germination seeds are surrounded by ovary which develops into fruit, thus fruit protect the seeds – for survival in new habitat

A husband and wife with seven children plan not to have anymore child. Based on your biological knowledge, explain the methods that can be recommended to them. [6 marks] Diaphragm ˗ inserted into vagina to cover the cervix to stop sperm from entering the uterus IUD ˗ fitted into uterus by doctor and can be left in the uterus (2 years) and prevent implantation Spermicide ˗ chemical cream/gel/foam is applied to vaginal walls before copulation and kill the sperms ejaculated into vagina Contraceptive pills ˗ prevents ovulation (by inhibiting the secretion of FSH and LH) Tubal ligation

BIOLOGY SPM ESSAY QUESTION COLLECTIONS ˗

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both the fallopian tubes are cut and tied (in an operation) causes the ovum cannot reach the part of Fallopian tube, fertilization is not occurred

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Inheritance and Variation

Melaka 2010 1

(a)

Diagram 1.1 and 1.2 shows the distribution of two type of variations in human.

Diagram 1.1

Diagram 1.2

With suitable examples, explain the type of variation for characteristic P and characteristic Q. [4 marks] P ˗ Height // weight ˗ continuous variation because have differences very slightly ˗ Controls by environment. Q ˗ Blood type ˗ discontinuous variation ˗ Controls by genetics. (b)

Diagram 1.3 shows few stages that involved in the production of insulin hormone through genetic engineering technology.

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Diagram 1.3 By using your biology knowledge, explain how this technology can be use in insulin hormone production. [6 marks] ˗ The gene for the insulin is isolated from human pancreas cell ˗ The bacterial plasmid is isolated (DNA found in bacteria) ˗ The bacterial plasmid is cut by using enzyme ˗ The enzyme used to incorporate gene for insulin production into the plasmid ˗ the bacteria are cultured in bioreactor ˗ the plasmid replicate as a bacteria divide asexually . ˗ the bacteria can produce insulin in large quantity, purified and isolate. (c)

Diagram 1.4 shows differences among cats. Diagram 1.5 shows the factors affected the differences.

Diagram 1.4

Diagram 1.5 Explain how these factors in the diagram will cause the differences among the cats in Diagrams 1.4. [10 marks] Meiosis ˗ produce varies gamet with different genetic contents; ˗ through homologous chromosomes random assortment during metaphase 1 Fertilization 62

BIOLOGY SPM ESSAY QUESTION COLLECTIONS ˗ ˗

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random fertilization between sperm and ovum produce zygote with varies genetic materials.

Crossing over ˗ crossing over occurs between the homologous chromosomes during prophase 1 ˗ result recombinants gens ˗ produce varies gamete cells Perlis 2010 2

(a)

Figure 2 shows various types of thumbprints.

Figure 2 (i)

Explain the type of variation shown in Figure 2. [4 marks] ˗ ˗ ˗ ˗ ˗

(ii)

Discontinuous variation Contrasting features No intermediate values Caused by genetic factors Can be inherited

Compare the variation shown in figure 9 with the type of variation shown by body mass. [6 marks] Body mass

Thumbprints

Continous variation

Discontinous variation

Features change gradually

Contrasting features

Intermediate values

No intermediate values

Caused by genetic factor and affected by environmental factors Cannot be inherited if characteristic affected by environmental factors Graph shows normal distribution

63

Caused by genetic factor Can be inherited Graph shows discrete distribution

BIOLOGY SPM ESSAY QUESTION COLLECTIONS (b)

Two parents who are both thin and are able to roll their tongues have a son who is fat and is able to roll their tongue. Explain how this happens. [10 marks] ˗ Thin parents can have a fat son even though the son inherits genes for thinness from his parents ˗ Body size is affected by environmental factors ˗ Continuous variation ˗ Due to diet, the size of body changes ˗ The ability to roll the tongue is determined by genetic factors ˗ Alleles for the ability to roll the tongue can be inherited ˗ Genes for this characteristic is dominant ˗ Hence, the son can roll his tongue

Kedah 2010 3

(a)

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Diagram 3.1 shows some examples of variation in human.

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Diagram 3.1 (i)

Based on Diagram 3.1, state the examples of continuous variation and discontinuous variation. [2 marks] Continuous variation : body weight, height Discontinuous variation : types of earlobe, types of finger print.

(ii)

State four differences between continuous variation and discontinuous variation. [4 marks]

(b)

Diagram 3.2 (a) and (b) show two examples of hereditary diseases.

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Diagram 3.2 Explain one characteristic of each disease. [4 marks] Albinisme ˗ Albinisme is caused by the change in gene // mutation ˗ Body / skin unable to produce black pigment (melanin) ˗ The skin and hair of albinos are white // their eyes are pink. Sickle cell anaemia ˗ Sickle cell anaemia is caused by the change in the genes // mutation. ˗ haemoglobin produced is not normal / abnormal ˗ Abnormal haemoglobin unable to bind / transport / carries with oxygen efficiently. ˗ The patient will always feel weak / cannot carries out vigorous activities. (c)

Diagram 3.3 shows an experiment to show the differences between two ginger plants which is obtained from tissue culture and are planted in two different environments.

Diagram 3.3

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BIOLOGY SPM ESSAY QUESTION COLLECTIONS (i)

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Explain the abiotic factors that cause the differences between the two ginger plants in set A and set B. [8 marks] Sun light ˗ Plants need light energy to carry out photosynthesis for growth ˗ Set A, plants are obtain more / exposed to sunlight // Plants in set B obtain less sunlight / not exposed to Sunlight. ˗ Growth rate of plants in Set A is higher than plants in Set B. Space ˗ Plants need (space) to grow a large root system / leaves ˗ Plants able to absorb sufficient water and minerals/sunlight. ˗ Set A, plants have larger space for the root and leaves to Grow // Plants in set B have smaller space for the root and leaves to grow. Soil / minerals ˗ Plants need mineral for (healthy) growth. ˗ Loam soil provides more minerals in Set A. // Sandy loam soil in Set B contains less minerals. ˗ Loam soil able to trap / store water better than sandy loam soil.

(ii)

Explain the role of tissue culture in this experiment. [2 marks] ˗ ˗

Plantlets from tissue culture have the same genetic material. This is to show /ensure/proof the differences of plants in Set A and Set B are not caused by genetic factor / have the same genetic material. // This is to show /ensure/proof the differences of plants in Set A and Set B are caused by abiotic factors.

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Biology Essay

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