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  2. 2. Chapter 2 : Cell Structure and Cell Organisation  Phagocytosis The pseudopodia are also used for feeding. Amoeba sp. engulfs food by phagocytosis. Amoeba sp. is a holozoic organisms which feed on microscopic organisms such as bacteria. The presence of food causes Amoeba advance by extending its pseudopodia. The pseudopodia encloses the food which is then packaged in food vacoule. The food vacoule fuses with lysosome and the food is digested by hydrolitic enzyme called lysozyme. The resulting nutrients are absorbed into the cytoplasm.  Comparison between the structure of animal and plant cell Similarities Smart Exam Tips ! - Comparison include similarities and differences - Both have a nucleus, cytoplasm, a plasma membrane, Golgi apparatus, mitochondria, endoplasmic reticulum and ribosomes. Smart Exam Tips ! - Use word BOTH for similarities 2 BIOLOGYLOVE second edition 2.0/2012
  3. 3. Differences Animal cells Do not have fixed shape Do not have cell wall Do not have chloroplast Do not have vacoule (if have, vacoule is only small and numerous) Carbohydrate is stored in the form of glycogen Have centrioles But Smart Exam Tips ! - Use word BUT for differences Plant cells Have fixed shape Have cell wall Have chloroplast Mature plant cell have a large central vacoule Carbohydrate stored as starch Do not have centrioles  The density of organelles in specific cells Type of cells Organelles found abundantly (high density) Sperm cells Mitochondria Smart Exam Tips ! Muscle cells - This question Meristematic cells always been asked in Paper 1 Palisade mesophyll cells Chloroplast and 2 Pancreatic glands Ribosome/RER/Golgi apparatus - SPM Question Cell in salivary gland Extra notes : please memorise all the cells ( shape and the function). Please know how to differentiate all the cells based on the structure and function. – SPM Questions 3 BIOLOGYLOVE second edition 2.0/2012
  4. 4. Chapter 3 : Movement of Substances Across the Plasma Membrane  Simple Diffusion Net movement of molecules or ions from a region of higher concentration to a region of lower concentration. Going down concentration gradient until an equilibrium is achieved. The particles are distibuted equally throughout the system.  Osmosis : Diffusion of water Net movement of freely moving water from a region of lower solute concentration to a region of higher solute concentration through a semi-permeable membrane.// Net movement of water from region higher water concentration to a region of lower water concentration through a semi-permeable membrane.// Net movement of water from hypotonic region to hypertonic region through a semi-permeable membrane. **Choose any one 4 BIOLOGYLOVE second edition 2.0/2012
  5. 5.        Facilitated Diffusion For water soluble molecules//molecules which are not soluble in lipids (ions, nucleic acid, amino acids and glucose) Carrier Protein The carrier protein function by binding to the molecules to pass through the plasma membrane. The molecules move to the carrier protein which is specific for the molecules. Molecules bind with the carrier protein at the active site. Carrier protein changes its shape and pass the molecules through the plasma membrane.  Active Transport Movement of molecules or ions against the concentration gradient across the plasma membranes. Requires both carrier proteins and expenditure of energy. Energy from ATP (adenosine triphosphate) that is generated during respiration in the mitochondria. Has active sites which bind to the ATP molecules. The carrier protein changes shape when the phosphate group from the ATP molecule binds to it Then the solute is moved across the plasma membrane.  Animal and plant cells in an isotonic solution Solution in which the solute concentration is equal to that of the cytoplasmic fluid. Water diffuse in and out of the cells at equal rate. No net movement of water. Cells retain its normal shape. 5 BIOLOGYLOVE second edition 2.0/2012
  6. 6.  Hypotonic solution Hypertonic  Hypertonic solution solution  Concentration of solute outside a cell is lower than  The concentration of solute in the concentration of solute inside cell. solution is higher than the concentration Animal cells of solutes within the cell sap.  Cell placed in hypotonic solution.  Hypertonic to the cell sap of the cell.  Solution is hypotonic to the cell sap of the cell. Animal cells  Net movement of water into the cells via osmosis.  Net movement of water from inside to  Cell swells up. the outside of the cell.  When extremely hypotonic, cells will eventually burst  Cells shrink//shrivel, internal pressure  Cannot withstand the osmotic pressure because of thin plasma decrease. membrane.  Red blood cells immersed in hypertonic  E.g : red blood cells (haemolysis) solution , the cell shrink and the plasma Plant cells membrane crinkles up.  Do not burst  Cell undergone crenation.  Rigid cell wall. Plant cells  Water diffuse into vacoule of cell via osmosis through  Water diffuse out via osmosis. a semi-permeable membrane.  Vacoule and cytoplasm shrink and  Cell swells up and becomes turgid plasma membrane pulls away from the  Tugor pressure in plant. cell wall.  Supporting the plant.  This process called plasmolysis. Exam tips : To answer Question on Osmosis 1. Mention about the solution (whether HYPERTONIC or HYPOTINIC) to the cell sap of the cell. 2. Water diffuse into/out of the cell via OSMOSIS 3. What happen to cell (plasmolysis, crenation, turgid, haemolysis) 6 BIOLOGYLOVE second edition 2.0/2012
  7. 7. Similarities between facilitated diffusion and active transport S1- Both (ways of transportation)need carrier protein. E1- To bind with molecules/ion/substrate/examples S2- Both transport specific molecules only. E2- Because the carrier protein have specific site to certain molecules. S3- Both processes occur in living cell. E3- Because carrier protein need/can change shape to allow substances to move across. Sodium Potassium Pump P1 P2 P3 P4 P5 P6 The concentration of sodium ions is higher on the inside of the cell The sodium ions approach the carrier protein. The carrier protein has a site for the ions to bind with The carrier protein binds to the sodium ions. The ATP molecule is split into Adenosine diphosphate (ADP) and phosphate(P). The phosphate group the attach itself to the carrier protein. The splitting of ATP releases energy to the carrier protein. Energy from the ATP changes the shape of carrier protein. This cause the carrier protein to release the sodium ions outside of the cell 7 BIOLOGYLOVE second edition 2.0/2012
  8. 8. Examples of transport of substances Transport process Simple diffusion Examples - Facilitated diffusion 8 - BIOLOGYLOVE - Ions intake by root hairs of a plant Gaseous exchange in the alveoli and blood capillaries - Osmosis Active transport Absorption of digested food in the villus Absorption of water by root hair cell Example of question Explain how red blood cell burst F1 the solution outside the cell is hypotonic to the cell sap E1 water molecules diffuse into the cell by osmosis E2 the plasma membrane is too thin to withstand the osmotic pressure inside the cell E3 So the cell burst/haemolysis occured second edition 2.0/2012
  9. 9. This how you answer the question Flaccid cell F1 : the cell sap is hypotonic to the solution F2 : water diffuse out from the cell via osmosis F3 : cytoplasm shrink//plasmolysis occured F4 : cell becomes flaccid Turgid cell F1 : the cell sap is hypertonic to the solution F2 : water diffuse into the cell via osmosis F3 : the cell swells up//vacoule becomes bigger F4 : the cell becomes turgid Percent change in mass ofpotato 25 20 At this stage, the sucrose solution is isotonic to the cell sap of the potato Water diffuse into and out of the cell via osmosis at equal rate P 15 10 At Q - 5 0 -5 At P - Sucrose molarity (mol) 0.2 0.4 0.6 -10 9 BIOLOGYLOVE 0.8 1.0 Q - The solution is hypotonic to the cell sap. Water diffuse into the cell via osmosis. Cell becomes turgid. That is why the mass increased. The solution is hypertonic to the cell sap. Water diffuse out from the cell via osmosis. Cell plasmolysed. That is why the mass decrease second edition 2.0/2012
  10. 10. Chapter 4 : Chemical Composition of the Cell Phosphate group carbohydrate Nitrogenous base Adenine (A), Guanine (G), Cytosine (C), Thymine (T) monosaccharides Nitrogenous base       polysaccharides disaccharides cellulose glycogen SPM 2011 Pentose sugar  Complementary base pairing A--------T C--------G G--------C T--------A starch ‘Lock and key’ hypothesis The substrate molecule fits into the active site of the enzyme molecule. The substrate is the ‘key’ that fits into the enzyme ‘lock’. Various types of bonds such as hydrogen and ionic bonds hold the substrate in the active site forming the enzyme-substrate complex. Once the complex is formed, the enzyme changes the substrate to its product. The product leaves the active site. The enzyme is not altered by the reaction and it can be reused. 10 BIOLOGYLOVE second edition 2.0/2012
  11. 11. 2 types of nucleic acid  Deoxyribonucleic acid (DNA)  Ribonucleic acid (RNA) DNA found in  Nucleus of a cell  Chloroplast  Mitochondria LIPID Energy rich organic compound. Contains phosphorus and nitrogen. Insoluble in water. Includes fats, oil, waxes, phospholipids, steroids. TRIGLYCERIDES DNA contains genetic information about an organism RNA found in  Cytoplasm  Ribosomes  Nucleus condensation hydrolysis The importance of Nucleic acids Store genetic information The stored genetic information can be duplicated/copied for transmission Stable in storing genetic information within the lifetime of organism Enable the transmission of genetic information from on egeneration to next generation glycerol 3 molecules of fatty acids triglycerides PROTEINS Amino acid as the basic unit (monomer) Build new cell for growth. CARBOHYDRATES Provide energy during respiration. Build cell wall (cellulose) in plants. External skeleton of insects. 11 BIOLOGYLOVE second edition 2.0/2012
  12. 12. Protein Structure Aspect Unsaturated fats Type s of chemical bonds All covalent bonds between carbon atoms single C - C Existence of double covalent bonds between carbon atoms C = C Reactivity Less reactive More reactive because of double bond State of matter at room temperature Solid (fats) Liquid (oil) Source Mainly from animal products : red meat, chicken fat, buuter and coconut oil Mainly from plant : Vegetable, palm/corm/olive Effects on blood cholestrol level Tertiary structure  Enzymes  Hormones  Antibodies  Plasma proteins Saturated fats Increase level of bad cholestrol Contains more cholestrol Contains less cholestrol Quartenary structure  Haemoglobin  Pore protein 12 BIOLOGYLOVE second edition 2.0/2012
  13. 13.                   General characteristics of enzymes Effects of temperature on enzyme activity Alter or speed up the rates of chemical reactions  At low temperature, reaction takes place slowly. Remain unchanged at the end of reaction.  As temperature increases, movement of substrate increase. Do not destroyed by reactions they catalysed.  Increase their chances of colliding with each other Have specific sites called active site to bind and with the active site of the enzymes. with specific substrates.  At optimum temperature, the reaction is at Needed in small quantities. maximum rate. Reaction are reversible  Beyond the optimum temperature, rate of reaction Can be slowed down or stopped by inhibitors. will not increase. E.g: lead and mercury  Bonds that hold enzyme molecules begin to break. Require helper molecules, called cofactors.  Actives sites destroyed. Inorganic cofactor : ferum, copper  Enzyme denatured. Organic cofactor: water soluble vitamins, B vitamins . Extracellular enzyme Extracellular enzyme is produced in a cell, then packed and secreted from the cell. It catalyses its reaction outside the cell. An example is amylase. The nucleus contains DNA which carries the information for synthesis of enzymes. Protein that are synthesised at the ribosomes are transported through the spaces within the rough ER. Proteins that depart from the rough ER wrapped in vesicles then bud off from the membrane of the rough ER. These transport vesicle then fuse with the membranes of the golgi apparatus and empty their contents into the membranous space. The proteins are further modified during their transport in the Golgi apparatus. For example, carboohydrates are added to protein to form glycoproteins. Secretory vesicles containing these modified protein bud off from the Golgi apparatus and travel to the plasma membrane. Enzymes are released. 13 BIOLOGYLOVE second edition 2.0/2012
  14. 14. What is monosaccharides? Glucose Fructose Galactose Exam tips : Glucose + monosaccharides Exam tips : Addition of water is necessary. Must be written!! What is disaccharides? Maltose Sucrose Lactose Glucose + glucose Glucose + fructose Glucose + galactose condensation condensation condensation condensation maltose + water sucrose + water disaccharides + water Enzymes for substrates Starch Sucrose Lactose Maltose : amylase : sucrase : lactase : maltase lactose + water Reducing Sugar and Non-Reducing sugar To test for reducing sugar, Benedict’s test must be carried out. If the colour of Benedict’s solution changes from BLUE to BRICK-RED PRECIPITATE, that’s mean the solution contains Reducing sugar. Sometime sucrose can show positive result. Why? Because sucrose can be Reducing sugar is hydrolysed into glucose and fructose. All monosaccharides, maltose and lactose Non reducing sugar is All polysaccharides and sucrose Give negative result on Benedict’s test (colour does not change) 14 BIOLOGYLOVE Steps: 1. Add dilute hydrochloric acid and boil the solution. 2. When the solution is cooled, put a spoon of calcium carbonate to neutralise the solution. 3. Then test with benedict’s solution. 4. Then the colour will change. second edition 2.0/2012
  15. 15. Chapter 5 : Cell Division Where do mitosis occur? In plants, mitosis occur in meristematic tissues. What is meristematic tissues? Roots tips Shoot tips Bud tips Terminal buds Cambium In animal? All parts of the body except TESTES and OVARY CHROMOSOMES AND CHROMOSOMAL NUMBER This is a chromosome With sister chromatids 1 chromosome This also chromosome But single chromatids 1 chromosome also n = haploid 2n = diploid Human has diploid number (2n) of chromosomes which is 46 Sperm (n=23) + ovum (n=23)  zygote (2n=46) 15 BIOLOGYLOVE second edition 2.0/2012
  16. 16. Stages in mitosis       Pro  Meta  Ana  Telo Prophase Chromosomes in the nucleus condense. Chromosomes appear shorter and thicker. Consist of sister chromatid joined at the centromere. Spindle fibres begin to form. Centrioles migrate at opposite poles. At the end, nucleolus disappears and the nuclear membrane disintegrates. 16 BIOLOGYLOVE     Metaphase Chromosomes align at the metaphase plate//equatorial plate. Mitotic spindle are fully formed. Two sister chromatids are still attached to one another at the centromere. Ends when the centromere divides.    phase Anaphase Two sister chromatids separate at the centromere. Sister chromatids pulled apart at opposite poles. Chromatids are referred to as daughter chromosomes.   Telophase Chromosomes reach the opposite poles of the cell. Chromosomes uncoil and revert to their extended state(chromatin). Exam Tips : You can use this note to answer question about chromosome behaviour second edition 2.0/2012
  17. 17. Cleavage furrow         Cytokinesis in animal cell Process of cytoplasmic division. Begins before nuclear division is completed. Actin filament formed contractile ring. Contracts and constrict pull aring of plasma membrane inwards. Groove of cleavage furrow pinches at the equator between two nuclei. Cytokinesis in plant cell Vesicles join to form a cell plate. Cell plate grows until it edges fuse with the plasma membrane of the cell. Cell divides. Cellulose are produced by the cell to strengthen the new cell walls. Exam Tips : Chromosome : Gamete (ovum and sperm) contain half the number of chromosome (n=haploid)         17 BIOLOGYLOVE Uncontrolled mitosis Cell divides through mitosis repeatedly without control. Produce cancerous cells. Cancer is a genetic disease caused by uncontrolled mitosis. Disruption of cell cycle. Cancerous cells divides freely and uncontrollably not according to the cell cycle. These cells compete with surrounding normal cells for energy and nutrients. Cancer cells formed tumour. Tumour invade and destroy neighbouring cells. second edition 2.0/2012
  18. 18. Application of Mitosis Animal Cloning  1   4     3 2 5      6   Advantages of cloning Biotechnologists to multiply copies of useful genes or clones. Clones can be produced in a shorter time and in large numbers. Cloned plants, however, can produced flowers and fruits within a shorter period. Clones are better quality. Delayed ripening. Does not need polinating agents. Propagation can take place at any time. Disadvantages of cloning Long-term side effects are not yet known. May undergo natural mutations. Disrupt the natural equilibrium of an ecosystem. Clones do not show any genetic variations. Has the same level of resistance towards certain disease. Certain transgenic crops contain genes that are resistant to herbicides. These genes may be transferred to weeds through viruses. These weeds would then become resistant to herbicides. Cloned animals has shorter lifespan. Example of Question : Explain the technic used in animal cloning 18 BIOLOGYLOVE second edition 2.0/2012
  19. 19. Tissue culture Meiosis hormone Small pieces of tissue is cut (e.g : root/shoot) Plant cell divide by mitosis to form callus an undifferentiate mass of tissue Meiosis I 1. During prophase I, homologous chromosomes pair up (synapsis) and crossing over between non sister chromatids occurs. 2. During Metaphase I, homologous chromosomes align at the metaphase plate (equator, middle) of the cell. 3. During Anaphase I, homologous chromosomes separates and move to opposite poles. Sister chromatids are still attached together and move as a unit. 4. At the end of Telophase I, two haploid daughter cells are formed. Each daughter cell has only one of each type of chromosomes, either the paternal or maternal chromosomes. Meiosis II Plantlet are then transferred to soil where they grow into adult plant 19 BIOLOGYLOVE Cell in the callus develop into embryo 1. During Prophase II, synapsis of homologous chromosomes and crossing over between non-sister chromatids do not take place. 2. During Metaphase II, chromosomes consisting of two sister chromatids align at the metaphase plate (equator/middle) of cell. 3. During Anaphase II, sister chromatids separate, becoming daughter chromosomes that move to opposite poles. 4. At the end of Telophase II, four haploid daughter cells are formed. Each daughter cell has the same number of chromosomes as the haploid cell produced in Meiosis I, but each has only one of the sister chromatids. second edition 2.0/2012
  21. 21. Synapsis, Crossing Over and Chiasmata(singular : chiasma) Synapsis is the process where the chromosomes pairing up Crossing over is the process where non sister chromatids exchange segment of genetic material (DNA) Chiasmata is the point where the crossing over process occur 21 BIOLOGYLOVE Exam tips : If the question ask for the type of division, you must answer whether 1. Mitosis or 2. Meiosis If the question ask for stage, then you can answer 1. Prophase//Prophase I//Prophase II 2. Metaphase and so on..... Before you answer the question, look at the diagram//question whether it is mitosis or meiosis!!! second edition 2.0/2012
  22. 22. Exam tips : - Process in Meiosis II is likely same as Mitosis - The term use for Meiosis I is Homologous chromosome while in Meiosis II, the term used is sister Chromatids Similarities between Meiosis I and Meiosis II Both consist of four stages Both involve nuclear division Both involve cytokinesis Both have chromatids Why Meiosis is needed? Meiosis is needed to produce haploid gamete Meiosis only occur in the GONAD (TESTES and OVARY) Why gamete must be haploid? Aspect Meiosis I Reduce 2n chromosome to n Prophase Metaphase Anaphase Telophase Chromosome already replicated Homologous chromosomes synapse Chiasma forms and crossing over takes place Paired homologous chromosomes align at the equator Separation of homologous chromosomes to opposite poles Single cytokinesis 2 identical cell produced Meiosis II Divides the remaining set of chromosome in a mitosis like process No replication No synapsis No chiasma and no crossing over If gamete is not haploid, the number of chromosome in the organism will be double from the real number!! Sister chromatids align at the equator 46 Separation of sister chromatids to opposite poles Two cytokinesis 4 identical cell produced 23 46 23 Exam Tips : You have to master all the Comparison between Meiosis I and Meiosis II also between Mitosis and Meiosis 22 BIOLOGYLOVE second edition 2.0/2012 96 46
  23. 23. Chapter 6 : Nutrition Energy value of food (kJ g-1) ( ) ( ) Percentage of vitamin C in fruit juice = ( ) x 0.1% Test on food samples Concentration of vitamin C in fruit juice = Test for Reagent Observation Conclusion Starch Iodine solution Colour change from yellow to blue-black Change from blue to brick red precipitate Change from blue to purple Food sample contains starch Translucent mark Oily mixture on the surface of water Food contain lipid Food contain lipid Reducing sugar Benedict’s (refer chapter 4) solution Protein Lipid Biuret’s test (20% of sodium hydroxide solution and 1% copper(II) sulphate solution Filter paper Lipid Emulsion test 23 BIOLOGYLOVE Food contain reducing sugar Food contain protein x 1.0 mg cm-3 Exam tips: - The above formula always been used in the exam. So, you have to remember the formula. No formula provided in the exam paper unless it is given in the question. second edition 2.0/2012
  24. 24. Examples of essays    Digestion in mouth Secretion of saliva by three pairs of salivary glands Saliva contains the enzyme salivary amylase Begins the hydrolysis of starch to maltose. Salivary amylase Starch + water   maltose An additional digestive process occurs further along the alimentary canal to convert maltose to glucose. pH is maintained at 6.5-7.5      Digestion in stomach Epithelial lining of the stomach contains gastric glands. These glands secrete gastric juice. Consists of mucus, HCL and enzyme pepsin and renin. HCL make the pH around 2.0. High acidity destroy bacteria. Acidity stop the activity of salivary amylase enzyme.        pepsin Protein + water  polypeptides Renin coagulate milk by converting the soluble milk protein, caseinogen into soluble caesin. Stomach contents become a semi-fluid called chyme. Chyme gradually enter the duodenum.           24 BIOLOGYLOVE Digestion in small intestine Duodenum received chyme from stomach and secretion from the gall bladder and pancreas. Starch, protein and lipids are digested. Bile which produced by the liver and stored in the gall bladder enter the duodenum via the bile duct. Bile helps neutralise the acidic chyme and optimise the pH for enzyme action in duodenum. Bile salts imulsify lipids, breaking them down into tiny droplets. Providing high TSA for digestion. Pancreas secrete pancreatic juice into duodenum via pancreatic duct. Pancreatic juice contains pancreatic amylase, trypsin and lipase. Pancreatic amylase complete the digestion of starch to maltose. Trypsin digests polypeptides into peptides. Lipase complete the digestion of lipid into fatty acid and glycerol. Glands in the ileum (small intestine) secrete intestinal juice which contain digestive enzyme needed to complete the digestion of peptides and disaccharides. Peptides digested by erepsin into amino acids. Maltose digested by maltase into glucose. Disaccharides digested by its own enzyme into monosaccharides and glucose. second edition 2.0/2012
  25. 25. Summary of the digestion Ileum (small intestine) Have intestinal gland which secrete intestinal juice that contain enzymes : Mouth Have salivary gland to secrete saliva Saliva contain salivary amylase Salivary amylase will digest maltase Maltose + water Stomach Have gastric gland to secrete gastric juice Gastric juice contain enzyme pepsin and renin pH is acidic Salivary amylase glucose Starch + water pepsin maltose protein + water polypeptides lactase Lactose + water renin glucose + galactose Exam tips : sucrase Sucrose + water glucose + fructose erepsin Peptides + water caseinogen + water amino acids Please remember that enzyme trypsin always need alkaline medium (pH > 7) Pepsin and renin need acidic medium (pH < 7) Digestion is a popular question in SPM!!! Acidic medium is in Stomach Alkaline medium is in Duodenum Site of digestion : duodenum Digestive organ Digestive juice Liver Bile, bile salts Pancreas Pancreatic juice enzyme None Pancreatic amylase pH 7.6-8.6 7.1-8.2 Substrates and products Emulsification of fats Pancreatic amylase Starch + water Trypsin 7.1-8.2 maltose trypsin Polypeptides + water Lipase 7.1-8.2 25 BIOLOGYLOVE peptides lipase Lipid droplets + water casein fatty acid + glycerol second edition 2.0/2012
  26. 26. Digestion in Rodent and Ruminant (essay) F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F1 F2 F3 F4 F5 F6 Digestion of cellulose by ruminant Partially chewed food is passed to the rumen (largest compartment of the stomach). Cellulose is broken down by cellulase produced by bacteria. Part of the breakdown products are absobed by bacteria, the rest by the host. Food enters the reticulum. Cellulose undergoes further hydrolysis. The content of the reticulum, called the cud, is then regurgitated bit by bit into the mouth to be thoroughly chewed. Helps soften and break down cellulose, making it more accessible to further microbial action. The cud is reswallowed and moved to the omasum. Here, the large particles of food are broken down into smaller pieces by peristalsis. Water is removed from the cud. Food particles moved into obamasum, the true stomach of the ruminant. (e.g : cow). Gastric juice complete the digestion of protein and other food substances. The food then passes through the small intestine to be digested and absorbed in the normal way. Digestion of cellulose by rodent Caecum and appendix are enlarged to store the cellulose-digesting bacteria. The breakdown products pass through the alimentary canal twice. The faeces in the first batch are usually produced at night. Faeces are then eaten again. To absorb the products of bacterial breakdown. The second batch of the faeces are harder and drier. Allows rodent (give example) to recover the nutrients initially lost with the faeces. 26 BIOLOGYLOVE second edition 2.0/2012
  27. 27. Essays Explain three structural adaptation of intestinal for effective absorption of food Exam tips - When the question asked for adaptation, your answer must be in the form of STRUCTURE + FUNCTION - When the question asked for function, start your answer with the word TO P1 P2 P3 P4 P5 P6 The villi have microscopic projection in the epithelial cell called microvilli Both the villi and microvilli increases the total surface area of the ileum for the absorption of soluble end product of digestion A dense blood capillary network at each villus Enable the food substances absorbed to be carried away quickly The epithelial lining of the villus is one-cell thick Allows soluble food molecules to diffuse quickly into the villus Explain what happen to the product of digestion after they are absorbed in the Small intestine F1 Absorbed by blood capillaries at the villus P1 Blood capillaries at the villus absorb galactose, amino acid, minerals, vitamin P2 by simple diffusion through the epithelium of the villus P3 These substances are carried by the hepatic portal vein to the liver and then distributed to body cell by the circulatory system (CS) F2 Absorbed by lacteal at the villus P4 The products of fats digestion such as glycerol and fatty acid as well as vitamins are absorbed into the lacteal of the villus P5 From the ileum, the thoracic duct carries the content of the lacteal into the bloodstream via the left subclavian vein and is then distributed into body cells by the CS. 27 BIOLOGYLOVE Similarities between the digestive system and digestion process of rodent and ruminant Similarities S1 Both alimentary canal contain bacteria/protozoa P1 To secrete extracellular enzyme//to digest P2 To digest cellulose into glucose S2 Both have large surface area P3 To increase rate of diffusion Differences D1 Ruminant has 4 stomach chamber but rodent has 1 stomach chamber P1 Because ruminant have to digest glucose//rodent don’t have to digest cellulose D2 Ruminant has a small/short caecum but rodent has a big/long size caecum P2 Because ruminant do not digest cellulose D3 Most bacteria in reticulum but rodent most bacteria in caecum P3 To secrete cellulase enzyme D4 Ruminant, the food passes through the stomach chamber twice but for rodent, the food passes the stomach chamber once P4 To complete thedigestion//to absorb digested food D5 The food is regurgitated twice in mouth cavity(ruminant) but the food is regurgitated once in mouth cavity(rodent) P5 Food that enter in mouth cavity, oesophagus, rumen and reticulum are then regurgitated back in mouth cavity for ruminant second edition 2.0/2012
  28. 28. Assimilation of digested food In the Liver F1 Amino acids is needed to synthesis new plasma protein F2 When a short supply of glucose and glycogen occurs, the liver converts amino acids into glucose F3 Excess amino acid cannot be stored, so amino acids is broken down in the liver through process of deamination F4 During deamination, urea is produced and transported to the kidney to be excreted F5 Glucose in the liver is used for respiration F6 Excess glucose in body is converted into glycogen F7 by hormone insulin and stored in the liver F8 Once the glycogen store in the liver is full, excess glucose is converted into lipid by the liver F9 Lipids which enter the subclavian vein are transported in the bloodstream to body cells In the cell F1 Amino acids which enter the cells are used for synthesis of new protoplasm and the repair of damaged tissues F2 Also important to synthesis of enzymes and hormones F3 Also used in the synthesis of proteins of plasma membrane F4 Glucose is oxidised to produce energy during cellular respiration F5 Energy is used for various chemical process F6 Excess glucose is stored as glycogen in the muscle F7 Lipids such as phospholipids and cholestrol are major components of plasma membrane F8 Fats are stored around organ and act as a cushion that protect the organ F9 Excess fats are stored in the adipose tissue underneath the skin as reserve energy F10 When the body lacks of glucose, fats is oxidised to release energy 28 BIOLOGYLOVE F1 F2 F3 F4 F5 Formation faeces Faeces which contain dead cells that are shed from intestinal linings. toxic substances and bile pigments enter the colon by action of peristalsis. In colon, more water is absorbed. The undigested food residues harden to become faeces. Faeces contain undigestible residues that remain after the process of digestion and absorption of nutrients that take place in the small intestine. Exam tips There are only three types of food classes assimilated in the liver and the body cell, AMINO ACID(MONOMER OF PROTEIN), GLUCOSE AND LIPID. second edition 2.0/2012
  29. 29. Photosynthesis Mechanism P1 P2 Photosynthesis mechanism The formation of starch in plants is by the process ofphotosynthesis which occurs in chloroplasts. The two stages in photosynthesis are the light and dark reactions. P3 Light reaction: takes place in grana. P4 Chlorophyll captures light energy which excites the electrons of chlorophyll molecules to higher energy levels. In the excited state, the electrons can leave the chlorophyll molecules. Light energy is also used to split water molecules into hydrogen ion (H +) and hydroxyl ions (OH-) (Photolysis of water). The hydrogen ions then combine with the electrons released by chlorophyll to form hydrogen atoms. The energy from the excited electrons is used to form energy-rich molecules of adenosine triphosphate /ATP. Hydroxyl ion loses an electron to form a hydroxyl group. This electron is then received by chlorophyll. The hydroxyl groups then combine to form water and gaseous oxygen. P5 P6 P7 P8 Exam tips: - You have to memorise and understand the mechanism. - You also have to know about the structure of chloroplast - Each of the structure of the chloroplast plays important role P9 P10 P11 P12 P13 P14 P15 Dark Reaction: take place in stroma. Do not require light energy. The hydrogen atoms are used to fix carbon dioxide in a series of reactions catalysed by photosynthetic enzymes and caused the reduction of carbon dioxide into glucose. The glucose monomers then undergo condensation to form starch which is temporarily stored as starch grains in the chloroplasts. Extra : - In another words, carbon dioxide is reduced into glucose by the hydrogen atom 29 BIOLOGYLOVE second edition 2.0/2012
  30. 30. More essays Explain the diet for the following people A lady athlete: F1 An athlete is a very active person and has high rate of metabolism to produce energy. E1 The diet should include more carbohydrates to supply enough energy to carry out the vigorous activity in Exam tips: sports.// She needs to contract and relax her muscles frequently for her vigorous activities. //Energy is needed to contract the muscles. E2 You must be able to relate the diet with the needs of the people. The diet should include more protein to build new tissues to replace tissues that are dead or damaged. E3 - She also needs calcium, sodium and potassium to strengthen the bones and to prevent muscular cramp. A pregnant lady: F2 A pregnant lady has a high rate of metabolism to provide energy for herself and the baby. E4 The pregnant lady also needs more iron and calcium to build red blood cells to avoid anemia. E5 She needs a high quantity of calcium and phosphate to form strong teeth and bones for the baby. An old lady: F3 An old lady has low rate of metabolism as she does not need energy to grow. (age) E6 An old lady needs less carbohydrates and fats because she is less active and thus do not need much energy. E7 she needs more proteins, vitamins and minerals to replace dead tissues and maintain her daily activities E8 She needs calcium and phosphorus to prevent osteoporosis E9 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. 30 BIOLOGYLOVE second edition 2.0/2012
  31. 31. Chapter 7 : Respiration Respiration is the process of oxidation of complex organic substances with the release of energy utilizes oxygen an dremoving carbon dioxide in living cells There are two types of respiration Aerobic respiration (presence of oxygen) Anaerobic respiration (absence of oxygen) Aerobic Respiration (complete breakdown of glucose) Glucose + oxygen carbon dioxide + water + energy Anaerobic respiration in human muscle When doing vigorous activities E.g : running Need more energy Glucose Lactic acid + energy (150 kJ//2 ATP) Oxygen debt is said to have been paid when all the lactic acid has been Eliminated through increased breathing. 31 BIOLOGYLOVE Anaerobic respiration in yeast Glucose ethanol + carbon dioxide + energy also called as fermentation and is catalysed by the enzyme zymase Essays Compare the aerobic respiration and anaerobic respiration Differences Aerobic respiration Need oxygen Complete oxidation of glucose Produce water, carbon dioxide and energy Produce 36 ATP (2898 kJ energy) Occur in mitochondria But Anaerobic respiration No tion of need oxygen Not complete oxidation glucose Animal : lactic acid and energy Plant/yeast : ethanol, carbon dioxide and energy Produce 2 ATP. Some of the energy stored in lactic acid or ethanol Occur in cytoplasm Similarities S1 Both involve cell respiration S2 Both involve oxidation of glucose S3 Both produce energy S4 Both catalysed by enzyme second edition 2.0/2012
  32. 32. Respiratory structures and breathing mechanism in human and animals Respiratory structue is the organ for respiration Respiratiry surface is the site where the exchange of gases occur Organisms Respiratory structure Respiratory surface Human Lungs Alveoli Grasshopper/insects Tracheal system Trachiole Amoeba sp. No specific structure Plasma membrane Fish Gills Lamella/filament Frog Skin and lungs Skin/walled sac in the lungs Four common characteristics(adaptation) of the respiratory surface 1) Large surface area to maximize the exchange of gases by diffusion 2) Moist respiratory surface for gases to dissolve 3) Thin as one-cell thick for effective diffusion of gases 4) Network of blood capillaries for effective transportation of gases Adaptation of the filament F1 Have network of blood capillaries E1 To transport respiratory gases effeiciently F2 One-cell thick wall E2 To nesure diffusion of gases occured easily F3 Has numerous lamella E3 To increase total surface area (TSA) for diffusion of gases F4 Has counter current exchange mechanism E4 To allow the gaseous exchange efficiently Countercurrent exchange Exam tips : - Memorising the four common characteristics is important because you can use it to answer question on adaptions of all organisms Essays Adaptation of tracheal system F1 E1 F2 E2 F3 E3 F4 Have spiracle To allow oxygen and carbon dioxide to get in and out of the cell The spiracle have valve To allow the opening and closing of the trachea so that air can go in and out The trachea are reinforced with chitin(made up of protein) To prevent the trachea from collapsing The trachea branched into finer tubes called tracheole which are in direct contact to the cell and organ E4 To transport the respiratory gases quickly F5 The tips of the tracheole is one-cell thick wall and contain fluid(moist) E5 To allow the respiratory gases to dissolve F6 The tracheal system has air sacs E6 To speed up the movement of gases to and from the insect’s tissues 32 BIOLOGYLOVE P1 P2 P3 P4 Blood and water flow in opposite direction Maintains diffusion gradient Maximizing oxygen transfer from water to blood It is significant because ensure oxygen concentration is always higher in the water P5 So that oxygen will always diffuse to the blood capillaries Exam tips: - Respiratory gases is Oxygen and Carbon dioxide - For fish, the adaptation of moist respiratory surface is not suitable because fish is already in the water!!! second edition 2.0/2012
  33. 33. The adaptation of respiratory structure of amphibians(frog) Essays Anaerobic respiration in human muscle P1 During a vigorous exercise (running), the breathing rate is increased. P2 This is to supply more oxygen to the muscles for rapid muscular contraction. P3 P4 However, the supply of oxygen to muscles is still insufficient. and the muscles have to carry out anaerobic respiration to release energy. P5 The glucose is converted into lactic acid, with only a limited amount of energy being produced. An oxygen debt builds up in the body, when no oxygen use in energy production. High level of lactic acid in the muscles cause them to ache. After running, the athlete breathes more rapidly and deeply than normal for twenty minutes. There is recovery period after 10 minutes until it reaches 20 minutes when oxygen is paid back during aerobic respiration. About 1/6 lactic acid is oxidized to carbon dioxide, water and energy. P6 F1 E1 F2 E2 F3 E3 F4 E4 F5 E5 The skin of the frog is thin highly permeable to respiratory gases The skin/membrane of the lung is moist To dissolve respiratory gases The skin has alrge number of blood capillaries under the skin/ lungs have network of blood capillaries For efficient transport of gases The lungs consist of a pair of thin walled sacs connected to the mouth through an opening called glottis To allow gases from mouth move to the lungs The membrane of the lungs are thin To allow diffusion of gases to occur easily 33 BIOLOGYLOVE P7 P8 P9 P10 Anaerobic respiration in yeast P1 Yeast normally respires aerobically. P2 Under anaerobic condition, yeast carry out anaerobic respiration. P3 Produces ethanol. P4 Process known as fermentation. P5 Catalysed by the enzyme zymase. P6 Ethanol produced can be used in making wine and beer. P7 In bread making, the carbon dioxide released during fermentation of yeast causes the dough to rise. second edition 2.0/2012
  34. 34. Breathing mechanisms in man P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 Diaphragm is a muscular sheet in the body cavity separating the thorax from the abdomen. At the start of inhalation, the muscles of the diaphragm contract , making it less arched. This helps to increase the volume of the thoracic cavity and reduce the pressure of the thoracic cavity. Air rushes into the lungs. When the muscles of the diaphragm relax , it returns to its arched condition , reducing the volume of the thoracic cavity and increasing the pressure of the thoracic cavity. Air is forced out of the lungs. The muscles between the ribs are known as intercostals muscles. During inhalation the external intercostals muscle contracts and raise the lower ribs. This helps to increase the volume of the thoracic cavity and reduce the pressure of the thoracic cavity. Air rushes into the lungs. During exhalation the external intercostals muscles contract , the ribs return to their original position , reduce the pressure of the thoracic cavity. Air is forced out of the lungs. The alveoli are thin-walled air sacs with the lungs. These sacs are surrounded by a network of capillaries. During inhalation the alveoli are filled with air and gaseous exchange occurs between the alveoli and the capillaries. Oxygen from the alveoli diffuses into the capillaries while carbon dioxide diffuses from the capillaries into the alveoli. Transport of oxygen and carbon dioxide in the body P1 Gaseous exchange across the alveolus occurs by diffusion. P2 Diffusion of gas depends on differences in partial pressure between two regions. P3 The partial pressure/ concentration of oxygen in the air of the alveoli is higher compared to the partial pressure/ concentration of oxygen in the blood capillaries. P4 Therefore, oxygen diffuse across the surface of the alveolus and blood capillaries into blood. P5 The transport of oxygen is carried out by the blood circulatory system. P6 Oxygen combines with respiratory pigment called haemoglobin in the red blood cells. P7 To form oxyhaemoglobin. P8 When the blood passed the tissue with low partial pressure of oxygen, P9 Oxyhaemoglobin dissociates to release oxygen. P10 Carbon dioxide released by repairing cells can be transported by dissolve carbon dioxide in the blood plasma. P11 Bind to the haemoglobin. P12 As carbaminohaemoglobin. P13 In form of bicarbonate ions. P14 Carbon dioxide is expelled with water vapour from the lung. 34 BIOLOGYLOVE second edition 2.0/2012
  35. 35. Essays Describe how the change of oxygen and carbon dioxide content are regulated by the body F1 The higher level of carbon dioxide in the blood cause the drop of the pH value F2 The drop in pH is detected by central chemoreceptor in medulla oblongata F3 Then the central chemoreceptor send nerve impulses tto the diaphgram and intercoastal muscle F4 Causing (respiratory muscle) to contract and relax F5 Finally, increases the breathing and ventilation rate concentration of carbon dioxide F6 And pH value of the blood return to normal level 35 BIOLOGYLOVE second edition 2.0/2012
  36. 36. Chapter 8 : Dynamic Ecosystem Food chain Sequence of organism which energy is transferred/flow from trophic level to another trophic level by eating process. In food chain, the energy received by the organism in each trophic level is only 10% from the previous organism. 90% energy lost as heat. Example : the producer get 25000J energy from the sun, then how much energy is received by the secondary consumer? 1st consumer get : 10% from 25000J = 2500J 2nd consumer get : 10% from 2500J = 250J Food web is the interconnection of many food chains Why most food chain havenot more than 4/5 links? - Because animals at the end of the food chain would not get enough food/energy. Interaction between biotic components Parasitism (+ -) Mutualism (+ +) Commensalism (+ 0) The organism which always get negative effect or did not get any effect is always the host 36 BIOLOGYLOVE second edition 2.0/2012
  37. 37. Colonisation and succession in an ecosystem Term Species Definition A group of organisms that look alike and capable of interbreeding and producing fertile offspring The natural environment in which organism can get food, shelter, living space, nesting and breeding sites 1. The function of an organism or the role it play in an ecosystem 2. And the space it occupies Habitat Niche Example : the grasshopper eats grass in the field Population Community Ecosystem So the idea of an ecological niche is very simple. You just need to know where the animal or plant and what it does A group of organism of the same species living in the same habitat at the same time All the plant and animals species living within a defined area or habitat in an ecosystem A community of living organism interacting whith each other and with the non-living environment The role of pioneer species : Modify the environment, creating conditions which are less favourable to themselves. Make the condition more conducive to other species that called successor species. (in other words, the pioneer will sacrifice themselves for the successor species). Colonisation and succesion in mangrove swamp Pioneer species : Avicennia sp. (sea) Sonneratia sp. (river) Colonisation takes place in newly formed area where no life previously existed. The first colonizer is called pioneer species Adaptation of pioneer species  Have dense root system to bind the sand particle, hold water and humus.  Have root nodules containing nitrogen fixing bacteria to fix Nitrogen from atmosphere to form nitrate as fertilizer.  Have short life cycle/colonize open space faster.  When they die, their remains add to the humus content of the soil 37 BIOLOGYLOVE second edition 2.0/2012
  38. 38. Essays Explain the process of colonisation and succession in mangrove swamp F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 The pioneer species of a mangrove swamp are the Sonneratia sp. and Avicennia sp. The presence of this species gradually changes the physical environment of the habitat. The extensive root systems of these plants trap and collect sediments, including organic matter from decaying plant parts. As time passes, the soil becomes more compact and firm. This condition favours the growth of Rhizophora sp Gradually the Rhizophora sp. replaces the pioneer species. The prop root system of the Rhizophora sp. traps silt and mud, creating a firmer soil structure over time. The ground becomes higher. As a result, the soil is drier because it is less submerged by sea water. The condition now becomes more suitable for the Bruguiera sp., which replaces the Rhizophora sp. The buttress root system of the Bruguiera sp. forms loops which extend from the soil to trap more silt and mud. As more sediments are deposited, the shore extends further to the sea. The old shore is now further away from the sea and is like terresterial ground. Over time, terrestrial plants like nipah palm and Pandanus sp. begin to replace the Bruguiera sp. Adaptation of the pioneer mangrove species to survive and colonised their habitat (to overcome problem during colonisation) Problem faced by mangrove plant (Fact) F1 F2 Soft muddy soil/strong coastal wind Waterlogged condition of the soil//very little oxygen for root transpiration F3 The high content of salt makes the water soil hypertonic compared to the cell sap of the root cell(so water diffuse out from the plant and make the plant dehydrated) Excessive exposure to the sunlight//high rate of transpiration F4 F5 High mortality rate//low survival rate of seedlings 38 BIOLOGYLOVE P1 P2 P3 P4 P5 P6 P7 P8 Adaptive characteristics of pioneer mangrove plants (explaination) Highly branched root system to support themselves (avicennia) have breathing roots/pneumatophore to absorb oxygen from the atmosphere Gaseous exchange occcurs through pores/lenticel Cell sap of the root cells are hypertonic compared to the soil water Excess salt in the plant is eliminated by the salt gland (hydathode) The leaves have a thick cuticle/sunken stomata to reduce transpiration The leaves are thick/succulent to store water Have vivaporous seedling//the seeds are able to germinate while still attached to the mother plant second edition 2.0/2012
  39. 39. Colonisation and succession in pond Frequency : Pioneer : Elodea sp. and Hydrilla sp. (submerged) Successor 1 : Lemna sp. and Pistia sp. (floating) Successor 2 : Sedges and cattails (emergent) x 100% Density : Essays Explain how colonization and succession bring about the formation of primary forest P1 Activities of pioneer species (submerged plant) causes change in the environment/ habitat, make it more suitable for other species P2 The remains of plant/decayed bodies sinked/deposited in the pond bed P3 Water level in the pond decreases//pond becomes shallower P4 Also add nutrients to pond water/soil//changes water/soil pH P5 Favours the growth of floating plants(any example) to replace the pioneer species P6 Floating plants cover the water surface, preventing light from penetrating the water/cause less rate of photosynthesis in the pond P7 Results in greater rate of plant death which sink to the bottom/bed of pond P8 Raising the pond bed/making the pond shallower P9 Floating plants are gradually replaced by emergent plants (example of plant) P10 The successor causes further changes to the habitat/pond make it more favourable for emergent plants to grow P11 Finally, emergent plant are replaced by land/terrestrial community which dominates the area Percentage coverage : x 100% The capture, mark, release and recapture technique Population size : Hierarchy in the classification of organisms Population ecology Quadrat sampling technique This technic can be used to determine  Frequency  Density  Percentage coverage 39 BIOLOGYLOVE second edition 2.0/2012
  40. 40. Essay Nitrogen Cycle P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 Nitrogen fixing bacteria/Rhizobium sp. in the root nodules of legumes plant//Azotobacter sp/Nostoc Use nitrogen in the air to make nitrates/carries out nitrogen fixation Nitrates produced by the bacteria are absorbed by plants to make proteins When animal eats plants, the protein is transferred to animals Excretory nitrogenous substances/urea/waste material/faeces When plants/animal die The plants/animals are decomposed by decaying bacteria/saprophytic bacteria/fungi Breaks them down to ammonia/ammonium compounds Nitrifying bacteria/Nitrosomonas converts ammonium compound/nitrates into nitrites Nitrifying bacteria/Nitrobacter converts nitrites to nitrates Denitrifying bacteria converts nitrates into nitrogen, thus nitrogen content in the atmosphere is maintained What happen if there is no microorganism? P1 P2 P3 P4 No breakdown/decomposition of the dead organism Mineral ions, for example nitrates cannot be released/ Nitrogen cycle is stopped Soil become infertile/less nutrient in the soil Plants will die/photosynthesis cannot takes place 40 BIOLOGYLOVE second edition 2.0/2012
  41. 41. Chapter 9 : Endangered Ecosystem Green house effects F1 F2 F3 F4 F5 F6 Ultra violet(uv) from solar radiation is absorbed by the earth and some of them is reflected back to the atmosphere in the form of heat/infra red. Heat or infrared radiation cannot be reflected back to the atmosphere. Because it is trapped by green house gases such as CO2, nitrogen dioxide and methane. Heat/infrared warmed the surface of earth. Earth temperature increases. Essays (negeri Perak 2010) 41 BIOLOGYLOVE second edition 2.0/2012
  42. 42. Eutrophication P1 P2 P3 P4 P5 P6 P7 P8 P9 Excessive fertilizer/animal organic waste from agricultural land /farming area flows into river nearby when it rains The presence of more minerals/organic substances Promotes algal growth /growth of aquatic plants in the river/ alga bloom The surface of the river is covered up by the algae(which grow extensively) The plants in the lower depths of the water cannot obtain sunlight They are unable to carry out photosynthesis Hence, the plant die The number of aerobic bacteria / decompose the dead plants also increase They use more of the oxygen (in the water) during the composition P10 This reduces the concentration of oxygen in the water P11 Causes the death of more aquatic organisms P12 The biochemical oxygen demand (BOD) increases Essays (SPM Trial Johor 2011) 42 BIOLOGYLOVE second edition 2.0/2012
  43. 43. 43 BIOLOGYLOVE second edition 2.0/2012