(ii) 1. Process or modified centre of carbohydrate /protein/ lipid 2. Packaging centre of carbohydrate /protein/ lipid 3. Transpotation centre of carbohydrate /protein/ lipid Any 2 (b)(i) • Y containing cell sap/water/sugar/ mineral salt • when the vacuole gain water causing the vacuole expand and swell up • the plasma membrane push against the cell wall, cell become turgid Any 2 (c)(i) cloning/culture tissue
2m
2m
1m
(ii) 1. 2.
The explants/ tissue taken from the parent plant put it into the sterile culture medium containing nutrients and growth hormones 3. The explants divide by mitosis to form a callus 4. Cell in the callus develop into embryos & later into plantlets
4m
12 marks
1
No. 2(a)(i)
Marking Criteria
Marks
Able to match the following substrates with specific enzymes that involved in the digestive system of humans. Substrate
Enzymes
Lactose
Lactase
Sucrose
Sucrase
Starch
Amylase
Protein
Pepsin/Protease/Trypsin/Erepsin/Rennin
1 1 3 1 1
Note: 4 correct : 3 marks 2-3 correct : 2 marks 1 correct : 1 mark 2(b)
Able to draw the diagram in the spaces IV and V provided in Figure 1.1 to complete the mechanism of the enzyme reaction. Sample Answer
No. ( c )( i)
1+1
Marking Criteria
Marks
Able to describe characteristic of the enzyme is explained by this hypothesis Sample Answer
2
• Enzyme have specific sites called active sites (to bind to specific substrates) • Enzyme are highly specific in action // (that is) each enzyme can only
1 1
2
ITEM NO 3 (a)
(b) (i)
(b) (ii)
(c)
SCORING CRITERIA Able to state the differences between process X and process Y Answer : Process X Process Y Inspiration process Expiration process The external intercostal The external intercostal muscles contract / internal muscles relax / internal intercostal muscles relax intercostal muscles contract Diaphragm muscles Diaphragm muscles contracts/diaphragm move expand / diaphragm move downwards and flattened upwards and arched The rib cage to move The rib cage to move upwards and outwards downwards and inwards The volume of the The volume of the thoracic cavity to increase thoracic cavity to decrease The pressure of the The pressure of the thoracic cavity/lung thoracic cavity/lung decrease increase High atmospheric pressure High atmospheric of the outside forces air pressure inside the lungs into the lungs forces air out of the lungs Able to draw the changes to the 1 – Thin rubber sheet. 2 – Balloons Sample answer: 1 – The thin rubber sheet is pulled down / lower than the original position. 2 – Both balloons inflated Able to explain the relationship between the changes in the model of the lungs in (b) (i) and the actual respiratory system based on the following criteria : 1 – Diaphragm muscles contracts/diaphragm flattened. 2 – Causes increase in volume of thoracic cavity 3 – Causes air pressure in lungs/thoracic cavity to decrease 4 – Air is forced in Able to state the function of the thin rubber sheet Sample answer: To change the volume and pressure inside the model of
3
MARKS
REMARKS
1
1 1 1 1 1 1
3
Any three
1 1 2
1 1
3
1 1 1
1
Any three
the lung. 3 (d) (i)
(d) (ii)
Able to state the reason why the end of the J-tube is immersed in potassium hydroxide solution and is then followed by potassium pyrogallol solution. Sample answer : 1 – Potassium pyrogallol solution absorbs both oxygen and carbon dioxide // Potassium hydroxide solution absorbs carbon dioxide only Able to explain why there is an increase in the percentage of carbon dioxide in the expired air based on the following criteria : F – Process of producing carbon dioxide E – Carbon dioxide transport from cells to the lungs Sample answer : F – Carbon dioxide is the product of cell respiration (in the body) E1 – Carbon dioxide diffuses out from the cells (into the blood) to be transported) to the lungs (and removed through expired air) E2 – The diffusion of carbon dioxide into blood capillaries increased the concentration of carbon dioxide in expired air
1
1
1
1
1
3 12 m
4
No 4
Marking Criteria
Marks
a) X = glucose Y = amino acid Z = fatty acid and glycerol
3 correct - 3M
b) Able to draw one vilus that show the parts and following label.
R- Able to show following parts: - blood capillaries, epithelium, lacteal.
3
L- Able to label any of two from the following: Blood capillaries, epithelium, lacteal,
2 1
b) (ii)
absorption / simple diffusion / facilitated diffusion / active transport (reject diffusion) - one cell thick / very thin wall - a lot of blood capillaries
1
c)
1
d) deamination e) (i) blood circulatory system (ii) - nutrient Z / fatty acid and glycerol absorbed into the lacteal - (nutrient Z / lipid / lymph) travel into lymphatic vessels by contraction of skeletal muscles - (the lymph) from the left side drains into the thoracic duct // the lymph from the right side drains into the right lymphatic duct - (the thoracic duct) empties its lymph into the left subclavian vein // (the right lymphatic duct) empties its lymph into the right subclavian vein
No
Marking Criteria 5
Marks
1 1 (Any one) 1 1 1 1
5 5(a)
(b)(i) (b)(ii)
R: Avicennia sp. / Sonneratia sp. Description : pneumatophores roots for breathing / respiration in the waterlogged conditions / less oxygen
1
S: Rhizophora sp. Description: prop roots for support the plnts onto the muddy soil.
1 1 4m 1m
Succession -
1
The root system of pioneer species traps mud during high tide (as time passes) the soil becomes more harder and drier / compact and firm // the soil level becomes increase (this condition) favours the growth of Rhizophora sp. / succession by Rhizophora sp./ not suitable for the growth of Avicennia sp. / Sonneratia sp. 3m
(c) -
Viviparity seedlings // seeds that germinate while still attached to the parent tree
1m
-
Will be polluted by toxic chemical Population of animals / plants decreases
1 1 2m
(d)(i)
(d)(ii) -
Treat waste fromfactories before being disposed. Enforce the law and take action on anyone who pollutes
Any one 1 1 1m
TOTAL MARKS=12m
6
7
ITEM NO 6(a)
SCORING CRITERIA
MARK
REMARK
(i) Able to explain how the transport of oxygen and carbon dioxide takes place in the body cells Sample answers: P1: The blood circulatory system transport oxygen from the alveoli to the body cells. P2: Oxygen combines with the haemoglobin in the red blood cells P3: to form oxyhaemoglobin (which is unstable.) P4: Oxygen is carried (in form of oxyhaemoglobin) to the tissues (which have a low partial pressure of oxygen.) P5: The (unstable) oxyhaemoglobin breaks down into oxygen and haemoglobin again. P6: Oxygen (molecules are) transferred to the body cells P7: Carbon dioxide binds (itself) to the haemoglobin P8: (and is) transported in the form of carbaminohaemoglobin. P9: Carbon dioxide is (also) transported as dissolved carbon dioxide (in the blood plasma.) P10: Most of carbon dioxide is carried as bicarbonate ions (dissolved in the blood plasma.) P11: When the blood carrying carbon dioxide reaches the body cells, the carbon dioxide diffuses into the blood plasma and combines with the red blood cells. P12:Carbon dioxide reacts with water to form carbonic acid. P13:Carbonic anhydrase in the red blood cells catalyse the formation of carbonic acid. P14: The carbonic acid then dissociates into a hydrogen ions and bicarbonate ions.
1 1 1 1 1 1 1 1 1 1 1 1 1 1 6
MAXIMUM: 6 marks (ii) Able to describe the adaptations of the alveolus for gaseous exchange Sample answer: F1: The millions of alveoli P1: provide a large surface area for gaseous exchange. F2: The walls of the alveoli are moist P2: and this allows respiratory gases to dissolve easily to them. F3: The walls of the alveoli are very thin (one-cell thick) P3: forquick / easy diffusion of gases. F4: The alveoli are richly supplied8with blood capillaries P4: to increase the rate of diffusion / the rate of the transportation of gases MAXIMUM: 4 marks
