Cell Biology Properties of Cells Cell Theory 1. All organisms are composed of one or more cells 2. Cells are the smallest living things and are the basic units of organization 3. Cells arise only by division of a previously existing cell Cell Size and Limitation The advantages of a large surface area of volume ratio: 1. As cell size increases, volume increases more rapidly than surface area 2. The cell surface provides the only opportunity for interaction with the environment 3. There is more area for diffusion Prokaryotic vs. Eukaryotic Cells Characteristic Size of Cell Nucleus Flagella Cell Wall Plasma Membrane Ribosomes Chromosomes Cell Division
Prokaryotic Typically very small No nuclear membrane or nucleoli Consist of two protein building blocks Usually present and chemically complex No carbohydrates Smaller size (70S) Single circular chromosomes; lacks histones Binary Fission
Eukaryotic Typically larger Tue nuclear, consisting of a nuclear membrane Complex; consist of multiple microtubules When present, chemically simple Carbohydrates that serve as receptors are present Larger size (80S) Multiple linear chromosomes with histones arrangement Mitosis
Organelles Nucleus Structure: surrounded by the nuclear envelope and contains chromatin and nucleolus Function: controls all the cell’s activities because it contains DNA Nucleolus Structure: visible structure in the nuclear Function: produces ribosomes Cytoplasm Structure: consists of all organelles and cytosol combined Function: provides a place for cellular functions to occur
Centrosome Structure: made of microtubules Function: involved in creating microtubules called spindle fibers in mitosis Golgi Apparatus Structure: A stack of membrane bound vesicles Function: involved in packaging proteins and sending them out for use by the organism Lysosomes Structure: vesicles that contain enzymes Function: enzymes in the lysosome are used to break down food, old organelles and damaged cells Cell Membrane Structure: made of a phospholipid bilayer, contains membrane proteins Function: controls what enters and leaves the cell Mitochondria Structure: has two membranes and the inner membrane has many folds called cristae Function: is used during cellular respiration to produce energy for the cell Vacuoles Structure: a membrane bound sac that is larger in plant cells than in animal cells Function: used for the storage of water, food and wastes. In plant cells it helps maintain turgor pressure Cell Wall Structure: a rigid structure outside the membrane in a plant cell made of cellulose Function: provides structure to support the cell and a protective barrier for the cell Chloroplasts Structure: has a double outer membrane and contains many stacks of structures called thylakoids, which are covered with chlorophyll Function: Photosynthesis occurs in the chloroplasts on the surface of the thylakoids Smooth Endoplasmic Reticulum Structure: a network of membrane bound vesicles and tubules as a continuation of the outer nuclear membrane Function: some functions include lipid and steroid hormone synthesis and the breakdown of toxins in liver cells Rough Endoplasmic Reticulum Structure: A network of membranebound vesicles and tubules. It appears rough because it covered in ribosomes Function: Proteins made on the ribosomes are packaged and transported throughout the cell Ribosomes
Structure: made of rRNA and protein, contains two parts called the large and small subunit Function: proteins are synthesized on the ribosomes
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Cell Division Binary Fission Occurs in Prokaryotic Cells 1. DNA replication occurs for the naked DNA (no histones) to duplicate 2. DNA separates as cytokinesis occurs Cell Cycle Interphase = growth of the cell, protein synthesis, metabolic pathways Mitosis = the cell is duplicated Cytokinesis = the cytoplasm is split into two daughter cells Mitosis Occurs in Eukaryotic Cells 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase
Prophase 1. The nuclear membrane breaks down so all 92 chromosomes can fit across the cell 2. DNA condenses to form chromosomes and spindle fibers from the centrosomes on polar ends of the cell Metaphase 1. Chromosomes are moved to the central place in the cell 2. Spindle fibers attach to each sister chromatid at the centromere Anaphase 1. The sister chromatids separate by the spindle fibers and the centromeres divide Telophase 1. The sister chromatids relax into “messy” DNA 2. The nuclear membrane begins to reform around the DNA 3. Spindle fibers break down Cytokinesis in Animal vs. Plant Cells Animals: Microfilaments contract to form a cleavage furrow which then pinches off to form two daughter cells Plants: vesicles form in the middle and join to form a cell wall between daughter cells
Cell Cycle Regulation It is important that cells only grow when they are needed and not all the time
Cyclins are proteins that regulate the cell cycle by binding to enzymes called cyclin dependent kinases (CDK) The attachment triggers the other proteins to become active and carry out tasks specific to one of the phases of the cell cycle Cyclin D: coordinates cell growth and the start of a new cycle (present in G1, S, G2 and M) Cyclin E: starts the initial process of DNA replication (present in S) Cyclin A: induces DNA replication and activates DNA proteins (present in G2) Cyclin B: influences the formation of mitotic spindles and alignment of sister chromatids (present in M)
Membrane Structure Bilipid Layer The Bilipid layers of phospholids are amphipathic (both hydrophobic and hydrophilic). The phosphate head is hydrophilic while the fatty acid tails are hydrophobic. Cholesterol in Membranes Cholesterol keeps the membrane fluid and flexible by disrupted fatty acid tail packing so the membrane isn’t solid, the OH part of cholesterol stays near the hydrophilic ends of the membrane. Proteins Integral Proteins: span the hydrophobic and hydrophilic layers because they are amphipathic Peripheral Proteins: stay on the outside of inside but not through the membrane Glycoproteins: have carbohydrates on the end used for cell signal and communication, as well as selfrecognition
Membrane Transport Simple Diffusion Sending molecules through the Bilipid layer down the concentration gradient, mostly gases and small particles. Requires no energy or proteins, therefore it is passive transport. Facilitated Diffusion Requires an integral protein to move molecules down the concentration gradient, uses protein channels and is used for larger molecules therefore it is passive transport Active Transport Requires ATP to change the confirmation of a protein to pump molecules from low to high concentrations. Used for sugars, ions and large molecules.
Osmosis Osmosis is the movement of water molecules across a membrane from high concentration to low concentrations. Hypotonic Solution Cell has a higher solute concentration, water goes into the cell and the cell swells because water goes into the cell Hypertonic Solution Cell has a lesser solute concentration, water leaves the cell and the cell shrivels up Isotonic Solution The same percentage of solute is in the surrounding solution and the cell so the cell remains constant
Bulk Transport Endocytosis The process in which the cell takes in molecules by pinching off the plasma membrane 1. Phagocytosis = cell eating in which it takes in solid particles 2. Pinocytosis = cell drinking where it takes in extracellular fluid Exocytosis Molecules are ejected from vesicles as it binds to the cell membrane
Molecular Biology The Basics Organic vs. Inorganic Organic molecules have the presence of carbon Inorganic molecules does not contain carbon but are still necessary to life Important Elements and their Functions Sulfur = important element found in amino acids Calcium = found in bones and used for muscle contractions Iron = found in hemoglobin to carry oxygen Phosphorus = found in cell membrane structures
Carbohydrates Monosaccharaides Single sugars that contain carbon, hydrogen and oxygen Glucose = most simple sugar Fructose =fruit sugar Galactose = milk sugar
Disaccharides Two sugars joined by a covalent bond Sucrose = glucose + fructose Lactose = glucose + Galactose Maltose = glucose + glucose Dehydration Synthesis Two monomers join together into polymers while loosing water molecules. This happens as one monomer loses OH and the other looses H forming a glycosidic bond.
Hydrolysis The process to break down large molecules into monomers so they become unusable for the body, an enzyme adds water to a glycosidic bond, which breaks apart into OH and H. Polysaccharides Long chains of sugar used for strange because they are not watersoluble and are bonded by glycosidic bonds Starch = mainly found in plants and is a long chain of glucose Cellulose = long chain of glucose found in the cell wall Glycogen = found in animals for energy storage, long chain of branched glucose
Lipids (Fats) Triglyceride A monomer of a fat molecule A glycerol and three fatty acid tails are joined by condensation synthesis to form an ester bond and produce three molecules of water Insoluble in water (hydrophobic)
Saturated vs. Unsaturated Fat Saturated Fat: Since the fatty acid tails are straight, they are easily stacked and therefore become a solid at room temperature, and because it is solid it can clog arteries Unsaturated Fat: since fatty acid trails are bent they do not stack or store easily and are liquid at room temperature. The “CIS bond” with the hydrogen’s on the same side distinguishes an unsaturated fat.
Transfats The “trans tail” is classified because hydrogen’s are on different sides therefore it is not accepted by the body. Also the tail is not as bent therefore it can be solid at room temperature.
Carbohydrates vs. Lipids Carbohydrates: More easily digested than lipids so the energy stored by them can be released more rapidly. They are soluble in water therefore easily move in and out from storage. Lipids: Contain more energy than carbohydrates however lipids are insoluble in water and can only be utilized at lower levels of energy
Cholesterol Cholesterol is a waxy, fat like substance that the body uses in cells and nerves to make hormones, protect nerves, and make up membranes. It is found in foods of high saturated fats. Problems: Cholesterol is distributed through the bloodstream and if you have an excessive amount, it gets stored in the arteries as plaque and can cause coronary heart disease
Protein Functions Proteins Polymers of amino acids (polypeptide) Each sequence of amino acids identifies the protein Made of carbon, hydrogen, oxygen and nitrogen Rubisco An enzyme involved in carbon fixation in photosynthesis Immunoglobin A large Y shaped protein produced by the immune system to fight infection Collagen A protein that builds muscle, tendons and ligaments Rhodopsin A protein linked to a pigment found in the photoreceptor cells in the retina of the eyes, it recognizes light and sends the information to the brain Protein Folding 1. Primary = sequence of long amino acid chain 2. Secondary = side groups form together by hydrogen bonds to make shapes, either a beta sheet or an alpha helix. 3. Tertiary = formation of a 3D shape. There are four bonds that stabilize the shape. Hydrogen bond (OH binds with H) Hydrophobic Interaction Disulfide Bridge (SS) Ionic Bond (NH3 – O) 4. Quaternary = multiple 3D shapes form together
Formation of a Peptide Bond Dehydration synthesis occurs such that the OH from one amino acid and the H from another form water, which leaves the bond to form a peptide bond.
A polypeptide chain will always start and end with the same thing, highlighted in yellow in the diagram above.
Properties of Water Cohesion Factor H2O has surface tension Good for water transport in plants Thermal Factor High specific heat capacity (water needs a lot of energy to heat up) Regulates temperature in water because of hydrogen bonds Universal Solvent Water has a positive and negative side, which attracts ions to either side Hydrogen Bonding Temporary bonding (weak) between the positive hydrogen side and the negative oxygen side
Enzymes Enzymes Enzymes speedup chemical reactions as they serve as a catalyst Has a specific 3D shape with an active site that only fits one molecule The shape of the protein is dictate by sequence of amino acids Enzymes work to break down a specific substrate into a final product Enzyme Regulation Enzymes are tertiary folded (3D shape) there they can be irreversible denatured (no more active site), they need to be regulated because the body needs a balance between the substrate and the final product. Negative Feedback Regulation
The final product tells the first enzyme in the anabolic pathway to stop producing it when there becomes a surplus of the final product, or a shortage of the original substrate Example of this is threonine (amino acid) that gets turned into isoleucine, which can inhibit Enzyme 1 to prevent the product of the final product. Competitive Inhibition An inhibitor looks similar to a substrate and occupies the active site so the substrate cannot bind At high substrate concentrations there is less effect by the inhibitor as it is more likely the substrate will bind than the inhibitor To reverse you must add more inhibitors NonCompetitive Inhibition The final product binds with a site called the allosteric site to turn off enzyme activity Once the inhibitor binds and shifts off the active site, the substrate can no longer bind so the rate of reaction is always low To reverse you can remove inhibitors or add enzymes
Diagrams of Noncompetitive and Competitive Inhibition
DNA The structure of DNA/RNA Nucleic Acids (Nitrogenous Bases) Adenine (A) = purine (2 rings) Guanine (G) = purine (2 rings) Cytosine (C) = pyrimidine (1 ring) Thymine (T) = pyrimidine (1 ring) A + T, C + G because DNA is always 3 rings wide Sugar Phosphate Backbone
DNA consists of a phosphate and a deoxyribose (sugar) base The sugar/phosphate backbone does not change even though the sequence of ATCG pairings does change The nitrogenous bases (ATCG) are bonded with hydrogen bonds DNA has an antiparallel structure such that one side goes from 5’ to 3’, while the other goes from 3’ to 5’ and is in a double helix form RNA RNA is similar to DNA however the difference is that the base sugar is ribose, and instead of Thymine, RNA contains Uracil (U), which still pairs with A Meselson and Stahl’s Experiment Their experiment proved how DNA replicates in a semi conservative manner (such that there is always one parent strand and one daughter strand 1. Grew bacteria in an N15 medium, therefore DNA was tagged with N15 2. Removed bacteria and allows it to grow in N14 medium 3. Isolated the DNA from bacteria and place it in a solution of chloride in a centrifuge and spun it around, DNA containing just N15 was heavy and sunk in the solution, DNA that was half N15, floated in the middle and DNA that was purely N14 floated near the top
4. They observed that as more generations reproduced, that there was always some of the N15 present because of the semi conservation manner of reproduction Supercoiling of DNA 1. Double helix structure wraps around a nucleosome (made up of 8 proteins called histones) 2. Coiled into a 30nm chromatin fiber of packed nucleosomes 3. Coiled to form a chromosome Leading vs. Lagging Strand Leading Strand: the 5’ to 3’ end, is able to be synthesized continuously Lagging Strand: the 3’ to 5’ end therefore it must be synthesized discontinuously
DNA Replication Helicase Helicase unwinds DNA by breaking hydrogen bonds DNA Polymerase III Adds new DNA nucleotides to the 3’ end Primase Enzyme that adds RNA primer to start the lagging strand RNA Primer Gives DNA polymerase III a 3’ OH end to add nucleotides to DNA polymerase I Replaces RNA primer with DNA Ligase Joins the Okazaki fragments together with a phophodiester bond Gyrase Keeps DNA from coiling in front of helicase Steps in DNA Replication 1. Helicase unwinds the double helix and singlestrand binding proteins stabilize the unwound DNA 2. The leading strand is synthesized in the 5’ to 3’ direction by DNA Polymerase III 3. The lagging strand is synthesized discontinuously. Primase makes a short RUNA primer, which is extended by DNA polymerase III to form an Okazaki Fragment 4. After the RNA primer is replaced by DNA by DNA polymerase I, Ligase joins the Okazaki fragment
Transcription and Translation
Codon The threeletter fragment on MRNA AUG codon codes for start UAA, UAG, UGA codons code for stop Transcription The process in which DNA gets transcribed into mRNA 1. Initiation = RNA polymerase binds to DNA at the site of the promoter codon which tells the enzyme where the gene starts 2. Elongation = RNA polymerase makes a complimentary copy of DNA (using Uracil not Thymine) using anticodons 3. Termination = RNA polymerase reaches the terminator and disassociates. The mRNA exits the nucleus through the membrane pores to be translated. Translation 1. 5’ MRNA AUG codon binds with the small subunit. The tRNA with UAC anticodon brings Met (amino acid) and the large subunit joins 2. New tRNA with correct anticodon enters the A site (aminoacyl site) then an amino acid joins the polypeptide held in the P site (peptidyl site) 3. When end codon is reached, all parts disassociate
Repressors to Regulate Gene Expression A repressor is a protein that blocks transcription by binding to DNA to stop RNA polymerase If a molecule is present like lactose, it will find to the repressor changing the 3D shape and allowing RNA polymerase to synthesize lactase enzymes If the molecule is not present, the repressor binds to DNA to stop transcription of the gene that makes that enzyme
Environmental Factors to Regulate Gene Expression Genes exposed to different temperatures or UV can express differently For example, Siamese cats have a mutant gene that is turned on because of lower temperatures at the ears nose and paws so the fur turns black Nucleosomes to Regulate Gene Expression Adding different groups can modify histones found in nucleosomes 1. Acetyl Group 2. Methyl Group 3. Phosphate group DNA has a negative charge so if you add a group to the histones it would neutralize DNA charge and the histones won’t bind as tightly therefore increasing transcription (acetyl group), or it may prevent transcription by winding DNA more tightly (methyl group) PostTranscriptional Modification PremRNA can be spliced by a spliceosome to remove parts to create different proteins turning it into mature mRNA The parts that are removed are called introns and the parts that are kept are called exons
Basics of Cellular Respiration and Photosynthesis ATP Energy comes from breaking bonds between phosphate groups in ATP When phosphate is broken off, ATP become adenosine diphosphate plus phosphate ATP ADP + P Redox Reactions Oxidization: loss of electrons/hydrogen (OIL)
Reduction: gain of electrons/hydrogen (RIG) Anaerobic Respiration In the absence of oxygen, the cell goes through a process called fermentation 1. Alcohol fermentation glucose = ethanol + carbon dioxide 2. Lactic Acid Fermentation glucose = lactic acid Factors that affect photosynthesis 1. Irradiance Level = more light that is present, the more photosynthesis until a maximum is reached because there is only a finite number of chloroplasts 2. Carbon Dioxide = the more CO2, the more photosynthesis up to a maximum level because there is only a finite number of chloroplasts 3. Temperature = there is an optimal temperature for photosynthesis to occur ATP Synthase The pumping of protons establishes a concentration gradient. AS the protons fall back into the matric through ATP Synthase, oxidative phosphorylation occurs to create ATP.
Cellular Respiration Steps of Cellular Respiration 1. Glycolysis = occurs in the cytoplasm 2. Kreb Cycle = occurs in the mitochondria (matrix) 3. Electron Transport Chain = occurs in mitochondria (cristae) Glycolysis 1. A 6C glucose gets split into two 3carbon molecules by two molecules of ATP 2. Electrons and hydrogen are removed from the 3 carbon molecules to turn NAD into NADH (electron carrier) 3. Energy is removed to create ATP from ADP leaving two molecules of pyruvate NET GAINS 2 ATP 2 NADH 2 Pyruvates Link Reaction Pyruvate enters the mitochondria and undergoes oxidative decarboxylation to create Acetyl CoA. In this process, CO2 is lost from pyruvate, and electrons/hydrogen are removed to form NADH NET GAINS 2 Acetyl CoA 2 CO2 molecules 2 NADH
Kreb Cycle Both molecules of Acetyl CoA enter the matrix and go through the Kreb Cycle NET GAIN (per Acetyl CoA) 3 NADH 2 CO2 1 FADH2 1 GTP Electron Transport Chain 1. Hydrogen Ions are pumped into the intermembrane space by moving electrons alone integral proteins, biding H2 and O2 making 6H2O 2. ATP Synthase does oxidative phosphorylation to add phosphate to ADP to make ATP NET GAINS 34 ATP 6 H2O Mitochondria Labeled
Photosynthesis Photosynthesis Steps 1. Light Dependent Reaction = occurs on the thylakoids 2. Light Independent reaction (Calvin cycle) = occurs in the stroma Light Dependent Reaction Light energy is converted to chemical energy Chlorophylls is attached to thylakoid membrane along with other proteins to form photo stems, which absorb red and blue light Electrons within chlorophyll absorb energy from photons and become excited, moving them alone the protein chain Electron causes protein pumping used by ATP synthase to drive production of ATP Light Independent Reaction 1. Carbon Fixation = a carboxylase (Rubisco) catalyzes the carboxylation (adding carbon) of riblose biphosphase (RuBP) 2. Reduction = G3P is reduced to triose phosphate using reduced NADP and ATP. Triose phosphate is used to regenerate RuBP to product carbohydrates 3. Regeneration = RuBP is reformed using ATP Chloroplast Labeled
Chloroplast Structure and Function Large surface area of thylakoids = greater absorption of light Small space between thylakoids = faster accumulation of proton concentration gradient Compare Photosynthesis and Respiration Bot use a concentration gradient ATP is a final product by ATP synthase Both use electron carriers
Contrast Photosynthesis and Respiration RESPIRATION Mitochondria Uses NAD + FADH No light is required and makes water Oxygen is the final acceptor in the ETC
PHOTOSYNTHESIS Chloroplasts Uses NADP Plants split water using light energy NADP is the final electron acceptor in light reaction
Human Physiology Digestive System Parts of the Body Liver: Makes bile which helps with fat digestion Gallbladder: Bile is stored in the gallbladder and is added to the small intestine Large Intestine: Salt and water is absorbed from chyme thus converting it to feces Esophagus: connects the mouth to the stomach and pushes chyme down by peristalsis Pancreas: secretes enzymes into the lumen of the small intestine Small intestine: the location in which nutrients are digested and absorbed Rectum: stores feces and the anal cavity eliminates feces Chyme The pulpy acidic fluid made of bolus, which is food after being pushed past the pharynx Peristalsis The contraction of both circular and longitudinal muscles to push food through the digestive tract
Digestive System Diagram
The Stomach Holds chyme to be chemically broken down by enzymes and hydrochloric acid The stomach contains mucus cells to product a protective layer of mucus from hydrochloric acid and protease enzymes
Enzymes Responsible for Digestion Amylase Found In: salivary glands and pancreas Optimal Conditions: mouth at pH of 6, intestines at pH of 8 Action: breaks down carbohydrates Polysaccharides disaccharides Lipase Found In: pancreas Optimal Conditions: small intestine at pH of 8 Action: breaks down lipids Triglycerides glycerol + fatty acids
Nucleases Found In: small intestine Optimal Conditions: immobilized on the epithelium cells of the intestine Action: breaks down nucleic materials Nucleic acid, DNA, RNA nucleotides Protease Found In: stomach and pancreas Optimal Conditions: stomach at a pH of 1 Action: break down proteins Chain of amino acids amino acids Phospholipase Found In: small intestine Optimal Conditions: small intestine at a pH of 8 Action: breaks down phospholipids Phospholipid phosphate + fatty acid
Small Intestine
Villi in the small Intestine Villi increase the surface area of epithelium over which absorption is carried out. Villi absorb monomers as well as mineral ions and vitamins. Each villi covered in microvilli.
Lipid Absorption 1. Triglycerides simply diffuse through the villi membrane because it is made of phospholipids 2. Triglyceride is packed into a lipoprotein inside the villi cell 3. Lipoprotein goes through exocytosis into the lacteal, which transports fat and white blood cells through the lymphatic system Glucose Absorption 1. SodiumPotassium pump decreases sodium concentrations in the villi cell 2. Sodium and glucose enter passively using the sodium glucose transporter protein 3. Glucose gets sent to the blood through the glucose channel
Circulatory System Components of Blood Red Blood cells: iron in hemoglobin carries oxygen White blood cells: defends against infections and makes antibodies Platelets: help blood clot Plasma: water, glucose, minerals, salts and hormones Veins Carries deoxygenated blood to the heart Lower pressure Large lumen but verily thin walls Valves prevent blood from going downwards Muscles movement helps move blood Arteries Carries oxygenated blood away from the heart Higher pressure Thick muscular layer surrounding a smaller lumen No values because blood is pumped Cardiac Cycle
1. Deoxygenated blood flows into the right atrium then through the tricuspid value into the right ventricle 2. The right ventricle pumps the blood through the pulmonic valve into the pulmonary artery to the lungs 3. Oxygenated blood returns through the pulmonary vein into the left atrium 4. Blood passes through the bicuspid value into the left ventricle 5. The left ventricle pumps blood into the aorta to be transported to all parts of the body Diagram of the Heart
Pressure during the Cardiac Cycle Atrial Ventricular Diastole: atriums expand and fill with red/blue blood Atrial Systole: atriums contract (pressure increases) and blood goes into ventricles Ventricular Systole: ventricles contract and blood goes to either the aorta or pulmonary artery Capillaries Smallest blood vessels that deliver oxygen and remove waste from cells One cell thick for quick diffusion and connects arteries and veins Sinoatrial Node The sinoatrial node sends out electrical impulses that stimulate contraction creating the heartbeat Coronary Thrombosis This disease is a clot in the coronary arteries. Risks for this disease include high cholesterol, smoking and high blood pressure.
Endocrine System Endocrine System Organs that product hormones (a chemical made in one part of the body but used in another) Parts of the hormone system include: pituitary gland, thyroid, adrenal gland, pancreas and ovaries/testis Negative Feedback STIMULUS HOMEOSTATIC CONDITION RECEPTORS RESPONSE The response eliminates change and returns to homeostatic condition Thyroxin A hormone secreted by the thyroid gland to regulate metabolic rate (nutrient use) thus has the ability to control body temperature Insulin A hormone that causes glucose to be absorbed by liver or muscles for storage, you need insulin when blood sugar is high so glucose can be stored as glycogen. Secreted by β cells in the pancreas Glucagon A hormone that causes liver and muscles to release glucose into the bloodstream and helps turn stored glycogen into glucose Secreted by α cells in the pancreas Islet of Langerhans The area of the pancreas that makes hormones and contains β and α cells Melatonin A hormone secreted by the pineal gland to control circadian rhythms (sleep) Pineal gland produces more melatonin when light is dim and less when light is bright Type I Diabetes Cause: the immune system attacks and kills β cells Effect: glucose builds up in the blood instead of being used for energy Treatment: insulin injections or oral medication Prevention: it is not yet known what causes Type I diabetes however research shows it is strongly linked to genetics Type II Diabetes Cause: the body cannot properly use the insulin that is produced Effect: glucose builds up in the blood instead of being used as energy Treatment: healthy lifestyle and medications Prevention: controlling blood pressure/cholesterol and exercising and eating healthy
Respiratory System Alveoli Air sacs at the end of bronchioles that are covered in capillaries for gas exchange/diffusion Large surface area for gas exchange Type I Pneumocytes vs. Type II Pneumocytes Type I: Extremely thin alveolar cells that are adapted to carry out gas exchange Type II: Secretes a solution containing mucus that creates a moist surface inside the alveoli to prevent the sides from adhering to each other Gas Exchange 1. Deoxygenated blood comes from the pulmonary artery 2. Blood drops off CO2 3. Blood picks up O2 4. Oxygenated blood returns through pulmonary veins Inhalation Rib Cage: expands Diaphragm: contracts and moves downward Muscles: contract to pull ribcage both up and out Thorastic Pressure: decreases Air movement: oxygen goes into the lungs to the alveoli sacs Exhalation Rib Cage: contracts Diaphragm: relaxes and moves upwards Muscles: expands and relaxes to reduce space in chest Thorastic pressure: increases Air movement: air goes out of the lungs Lung Cancer Causes: tobacco, pollution, chemical carcinogens, exposure to radiation or hereditary Effect: infection of cells that line the bronchi Treatment: surgery, radiation, chemotherapy Emphysema Causes: tobacco, marijuana, pollution, exposure to fumes and dust Effect: gradually damages the alveoli causing them not to work properly and air becomes trapped Treatment: lung transplant, medication
Immune System Blood Clotting
1. Endothelial damage 2. Platelets release clotting factors 3. Prothrombin turns into Thrombrin which helps turn Fibrogen (soluble) into Fibrin (insoluble) Fibrin Fibrin net catches platelets and red blood cells to firm a scab to prevent pathogens from entering Skin and Mucous Membranes Skin: lower pH level to prevent bacterial growth Mucous: lines nasal and digestive tract and includes enzymes that can kill pathogens Antibodies Antibodies have multiple functions that help to destroy a pathogen. There is one antibody for one type of antigen, which is a chemical signal that is found on pathogens that trigger an immune response Roles of Antibodies Coagulate the pathogen (clumping) Lysis of the cell coat/membrane to help block adhesion to host Attaches to pathogen to make recognizable to white blood cells, which causes phagocytosis by macrophages/neutrophils B Cells 1. B cells encounter an antigen and respond by proliferating by mitosis 2. Some B cells differentiate into memory cells, which remain in the blood stream in case of a second exposure, while some differentiate into plasma cells, which secrete antibodies into the circulation Antibiotics Prevent membrane formation Affects DNA replication Can stop transcription and translation Blocks processes that occur in prokaryotic cells but not eukaryotic cells, which is why they do not work against viruses Florey and Chain’s Penicillin Test Penicillin: a chemical made by fungi used to treat competitive bacteria The Experiment: eight mice were injected with bacteria yet only four were treated with penicillin. After 16 hours, the four mice that did not receive treatment were dead. Bacteria 20x larger than viruses Noncellular and submicroscopic Contains: single chromosomes, organelles and enzymes Capable of independent reproduction Living because they feed, grow and reproduce
Viruses 20x smaller than bacteria Single celled organism Contains: central core of DNA surrounded by protein coat Only capable of reproducing inside other cells Nonliving because they do not feed or grow White Blood Cells Neutrophils: endocytosis to eat pathogens Macrophage: sends our hormone to signal more white blood cells Mast Cells: secretes factors that mediate vasodilation (delivery of blood plasma and cells to wound) SelfRecognition Glycoproteins are on the surface of every cell in your body and if glycoprotein is not present there will be an immune response Blood Type Antigens on the surface of red blood cells stimulate antibody production and immune system. If the wrong blood cell is transfused, antibodies will agglutinate (clump) the red blood cells together TYPE ANTIBODIES ANTIGENS CAN ACCEPT
A Anti B A A and O
B Anti A B B and O
AB None A and B A and B and O
O A and B None O
Allergies Mast cells are activated by a harmless pathogen and produce histamine. Histamine increases the blood supply to increase white blood cells in responses to heal inflammation. Specific Immune Response 1. Macrophages engulf pathogen by endocytosis after it displays antigen on the surface 2. Only B and T cells with correct match to antigen will be activated and multiplied 3. Helper T cells quickly multiply and produce specific B cells for the antigen (clonal selection), which can differentiate into plasma, and memory cells 4. In second exposure, antigen stimulates memory B cells to differentiate into plasma cells
Nervous System Human Nervous System Central Nervous System: brain and spinal cord Peripheral Nervous System: sensory and motor Somatic nervous system: controlled by the person, motor neurons and skeletal muscles Autonomic Nervous System: involuntary, nerves from internal receptors Neuron
Parts of Neuron Myelin Sheath: the layer of fat wrapped around the axon, each roll of fat is called a Schwann cell Node of Ranvier: the point between Schwann cells where impulses “jump” The Sodium/Potassium Pump Neurons pump sodium and potassium ions across their membranes to generate resting potential. Only 2K enter for every 3Na out therefore a negative interior potential is maintained. Nerve Impulses Depolarization: Sodium channels open, sodium enters the cell making the axon positive after threshold is reached Repolarization: Sodium channels close, potassium channels open and potassium leaves the cell making axon more negative Refractory Period: Much potassium leaves the cell that the nerve becomes too negative so excess potassium outside diffuses Action Potential: once an action potential is reached it is propagated along the nerve
Nerve Communication 1. Action potential reaches the synaptic cleft ad calcium ions enter the presynaptic membrane 2. Calcium causes exocytosis of neurotransmitters into synaptic cleft 3. Neurotransmitters bind to sodium channels on the postsynaptic membrane to allow sodium to flow into either that nerve or muscle 4. Neurotransmitters are broken down by enzymes and are absorbed to be recycled Acetylcholine and Neonicotinoid Acetylcholine: A neurotransmitters made of acetyl group and chorine used for muscle contractions Neonicotinoid: A synthetic compound that binds to acetylcholine receptors in insects causing the postsynaptic nerve to constantly produce action potential
Reproductive System Testosterone A gene on the Y chromosome causes the development of testes to secrete testosterone This hormone causes prenatal development of male genitals and sperm production and development of sale sexual characteristics during puberty A gene called SRV codes for TDF (testis determining factor) Sperm Diagram and Functions
Acrosome: breaks down the outer shell of the egg Male Reproductive System and Functions
Vas Deferens: carries sperm to the urethra Seminal Vesicle and Prostate Glands: Make semen in a high pH solution to protect the sperm
Estrogen/Progesterone Both hormones cause prenatal development of the female reproductive organs and secondary sexual characteristics during puberty Ovum Diagram and Function
Female Reproductive System Diagram and Function
Ovaries: produces eggs and estrogen Cervix: protects the fetus Fallopian Tube: collected egg and is place where fertilization occurs
IVF 1. Women take medication to increase the number of follicles developed in ovaries 2. Remove the eggs from the ovaries 3. Fertilize the eggs with donor sperm 4. Embryos grow on place and few selected ones are implanted into uterus
Menstrual Cycle Menstrual Phase Day 15 Menstruation occurs The lining of the uterus shed because progesterone is low FSH from the pitutatary gland causes a follicle to develop Proliferative Phase
Day 514 This is where the lining rebuilds to prepare embryo for implantation due to an increase in estrogen Ovulation Day The mature egg leaves the ovary caused by a spike in LH (luteinizing hormone) Secretory Phase Day 14end If implantation occurs, progesterone stays high to maintain the lining of the uterus If no implantation occurs, the levels of progesterone decrease and the cycle starts again
Fertilization External Fertilization No copulation Male gametes are shed into a large space reducing the chance of fertilization Many female gametes are produced Zygotes develop outside the male and female parents Internal Fertilization Copulation occurs Male gametes are shed into a confined space Few female gametes are produced Zygote is developed inside the mother for protection Process of Fertilization 1. Acrosome releases enzymes to break down zona pellucita 2. Nucleus of sperm enters the egg while tail remains outside 3. Tiny protein bags called corticle granuals are released after fertilization and bind to glycoproteins to harden zona pellucita Blastocyst Implantation At the uterus, the zona pellucita breaks and the blastocyst escapes to sink into the endometrium (lining of the uterus) Syncytiotrophoblast is secreted to try and find the maternal blood supply HCG The fetus produces a hormone called HCG, which stimulates the ovary to secrete progesterone during the pregnancy to maintain the lining of the uterus Oxytocin
During pregnancy, progesterone inhibits oxytocin, which facilitates uterine contractions. At the end of the pregnancy, fetus releases hormones to limit progesterone therefore the pituitary gland will make oxytocin Placenta The placenta facilitates the exchange of materials between mother and fetus At 9 weeks, the placenta takes over the production of hormones such as estrogen and progesterone Material Exchange between Mother and Fetus 1. Mothers blood brings nutrients such as glucose, lipids, water, hormones, antibodies and amino acids and bathes the blood around the villi 2. Fetal blood drops off carbon dioxide, urea, hormones and water 3. Gas exchange and nutrient exchange occurs over the villi surface so mother and babies blood never meet 4. Blood returns to the fetus via umbilical vein
Ecology Key Terms Species A group of organisms that have the potential to interbreed and produce fertile offspring Population A group of organisms of the same species that live in the same area at the same time Community A group of populations living and interacting with each other in an area Ecosystem A community and its abiotic environment Autotrophs Species that are able to make their own food from basic inorganic materials Heterotrophs Consumers that obtain their food from organic matter, can include herbivores, carnivores and omnivores Sapotrophs Bacteria and fungi that secrete enzymes onto organic matter and then absorb their nutrients Detrivores
Organisms that digest dead organic matter Food Chains A hierarchy of feeding relationship that influences how nutrients and energy pass through it Autotrophs start food chains since they are able to convert the suns energy into chemical energy. This chemical energy in carbon compounds passes through food changes as organisms consume Energy in Food Chains Only about 10% of energy passes onto the next trophic level. Energy losses can occur from cellular respiration, not absorbed or lost to decomposers, or the organism is not consumed
Carbon Cycling Carbon Cycling In the atmosphere, carbon is present as carbon dioxide gas Carbon dioxide is converted into carbohydrates and other carbon compounds by autotrophs Carbon dioxide enters the cells of autotrophs from the air or water by diffusion Carbon dioxide is produced during respiration and diffuses out of organisms In anaerobic conditions, methane is produced from organic matter and diffuses into the atmosphere When organic matter is not fully decomposed because of acidic or anaerobic conditions in waterlogged soils, peat forms Oil, gas and coal are formed from partially decomposed organic matter that has accumulated in porous rocks Combustion of biomass and fossilized organic matter produces carbon dioxide Greenhouse Effect Occurs when the concentration of greenhouse gases such as carbon dioxide and water vapor increases so more heat is trapped rather than reflected back into space therefore increasing global temperature
Classification of Biodiversity Hierarchy Species are classified using a hierarchy of groups called taxa. There are eight levels: 1. Domain 2. Kingdom 3. Phylum 4. Class 5. Order 6. Family 7. Genus – part of the name that indicates a group of species that are closely related 8. Species – defines a group of individuals that are capable of interbreeding
Phyla of the Plant Kingdom Bryophyta Plants in this phylum include mosses Usually small and grow in damp places because they have no vascular system Reproduce by way of spores They have no roots Filicinophyta This group includes mosses and ferns Have roots stems and leaves and possess internal structures Some have fibrous roots while other produce an underground stem called a rhizome Coniferophyta This group includes shrubs and trees, which are often large and evergreen Produce pollen rather than spores often in huge amounts They produce seeds Have needlelie leaves to reduce water loss Angiospermophyta This group includes all flowering plants, which are pollinated by wind or animals They produce seeds which are associated with a fruit or nut
Phyla of the Animal Kingdom Porifera This group contains the sponges They are aquatic and many produce a skeleton of calcium carbonate Cnidaria Sea corals and jellyfish They feed on other animals by stinging them with special cells called nematocysts Platyhelminthes These have a layer of cells and have a body cavity with a mouth and an anus Some are freeliving it water while others are parasites living in other organisms They have a flattened appearance Annelida This group contains lugworms, earthworms and leeches All annelids have bodies that are divided into sections called segments
