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BIOLOGY 2016.pdf 1

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FORM 1 1. INTRODUCTION TO BIOLOGY Specific Objectives - Definition of biology - Branches of biology - Importance of biology - Characteristics of living organisms - Cornparison between plants and animals - Practical Activities - Collecting, observing and recording external features of plants and animals By the end of the topic, the learner should be able to: a) define biology b) list branches of biology c) explain the importance of biology d) state the characteristics of living organisms e) state the main differences between plants and animals. 1. K.C.S.E 1995 PP1 No.1 Motor vehicles move, use energy and produce carbon dioxide and water. Similar characteristics occur in living organisms yet motor vehicles are not classified as living. Explain (3 marks)  They produce, they grow  Respond to stimuli/ irritability 2. K.C.S.E 2010 PP1 No.1 State the name given to the study of: (i)The cell (1 mark)  Cytology: Rej cell biology (ii)Micro--organism. (1 mark)  Microbiology 3. K.C.S.E 2011 PP1 No.4 State one use for each of the following apparatus in the study of living organisms. (a) Pooter (1 mark)  Sucking small insects / small animals from backs of trees and rock surfaces (b) Pitfall trap (1 mark)  A trap into which (small) animals fall and get trapped; examples of small animals e.g. insect / reptiles, arachnids 1

4. K.C.S.E 2012 PP1 No.1 How does nutrition as a characteristic of living organisms differ in plants and animals? (2 marks)  Plants make their own food from carbon (IV) oxide and water in the presence of light /photosynthesize/ autotrophic; while animals eat readymade food (some plants and animals heterotrophic;  If photosynthesis described all raw materials must be mentioned;  Carbon (IV) oxide the (IV) must be bracketed.  If sources of food for animals are mentioned then both plants and animals must appear. 5. K.C.S.E 2014 PP1 No.1 State the importance of each of the following in living organisms: (a)Nutrition (1 mark)  acquisition and utilization of nutrients; (b) Excretion. (1 mark)  elimination of metabolic wastes to prevent accumulation to toxic level; 2

2. THE CELL Specific Objectives - Definition of the cell - Structure and functions of parts of a light microscope - Use and care of the light microscope - Cell structure and functions as seen under - a light microscope - an electron microscope - Preparation of temporary slides of plant cells - Estimation of cell size - Cell specialization, tissues, organs and organ systems - Observe, identify, draw and state the functions of parts of the light microscope - Prepare and observe temporary slides of plant cells - Observe permanent slides of animal cells - Comparison between plant and animal cells - Observe, estimate size and calculate magnification of plant cells By the end of the topic, the learner should be able to: a) define the cell b) state the purpose of a light microscope c) identify the parts of a light microscope and state their functions d) use and care for the light microscope and state the magnification e) identify the components of a cell as seen under the light and electron microscopes and relate their structure to functions f) compare plant and animal g) mount and stain temporary slides of plant cells h) describe animal cells as observed from permanent i) estimate cell size j) state the differences between cells, tissues, organs and organ systems. 3

1. K.C.S.E 1995 PP1 No.2 Name the organelle that performs each of the following functions in a cell. (2 marks)  Protein synthesis – Ribosomes  Transport of cell secretions – Endoplasmic reticulum 2. K.C.S.E 1996 PP1 No.8 State two functions of cell sap (2 marks)  Store chemical salts/sugar;  Maintain shape of cell. Osmotic gradient that brings about movement of water. 3. K.C.S.E 1997 PP1 No.1 State the functions of the following cell organelles (a) Golgi apparatus  Packaging and transport of synthesized materials; Accept correctly named materials e.g glycoproteins  Transport of the packed materials, secretion of packed materials (b)Ribosomes  Manufacture/ synthesis of proteins. 4. K.C.S.E 1998 PP1 No.3 Which organelle would be abundant in: i) Skeletal muscle cell  Mitochondrion ii) Palisade cell  Chloroplasts 5. K.C.S.E 2001 PP1 No.7 Name the organelle in which protein synthesis takes place  Ribosomes 6. K.C.S.E 2004 PP1 No.7 State the function of the organelles: a) Lysosomes  Stores hydrolytic enzymes for destruction of worn out organelles / cells/ tissues / digestion of bacteria. / pathogens; Acc. Digestion of food / accept autolysis. b)Golgi apparatus  Processing / packaging synthesized and transporting of packaged cell materials;  Production of lysosomes/ secretions of packaged material; 4

7. K.C.S.E 2007 PP1 No.2 (a) What is the formula for calculating linear magnification of a specimen when using a hand lens?(1 mk)  Magnification = length of the drawing/image o length of the object (b) Give a reason why staining is necessary when preparing specimens for observation under the Microscope (1 mark)  It is adding a dye to the specimen to make the features clearer and distinguishable. 8. K.C.S.E 2007 PP1 No.3 Plant cells do not burst when immersed in distilled water. Explain (2 marks)  Plant cells have plasma membrane and cell wall. When the cell is placed or immersed in distilled water, the water is absorbed by osmosis. As cell becomes turgid, the cell creates an inward force, wall pressure that prevents the cell from bursting. 9. K.C.S.E 2007 PP1 No.4 State three functions of Golgi apparatus (3 marks)  Form vesicles that transport materials to other parts of the cell e.g. proteins.  Transportation secretions to the cell surface for secretion e.g. enzymes and mucus. Packaging of materials such as glycoproteins.  They form lysosomes 10. K.C.S.E 2008 PP1 No.12 State two functions of the endoplasmic reticulum (2 marks)  Transport of protein  Synthesis/ transport of lipids/ steroids  Site for attachment for ribosome. 11. K.C.S.E 2009 PP1 No.3 State the functions of the following parts of a light microscope (2 marks) (a) Objective lens  Magnification of the object/ image (b) Diaphragm  Regulates amount of light (falling on the object on microscope); Acc: Adjust control amount of light 5

12. K.C.S.E 2009 PP1 No.7 State the function of the following cell organelles  Ribosome (1 mark)  Site for protein synthesis. (b) Lysosomes (1 mark)  Contains lytic enzymes that break down worn out cells/ organelles / food materials o NB: Must mention effects of lytic enzymes 13. K.C.S.E 2010 PP1 No.3 State the function of: (a)Ribosomes (1 mark)  Synthesis of proteins (b) Lysosomes (1 mark)  Breakdown worn out cell organelles/large molecules and pathogens 14. K.C.S.E 2010 PP1 No.4 The diagram below shows a specialized plant cell. o (a)i) Name the cell (1 mark)  Root hair (cell) ii) Name the parts labeled D and E. (2 marks)  D – Cell wall  E – Cell sap (vacuole) b) State the function of the part labeled C. (1 mark)  Controls the functioning of the cell/ controls cell activities 15. K.C.S.E 2011 PP1 No.11 State two functions of the following parts of a light microscope.  Fine adjustment knob- Moves the body tube through smaller distances to bring image/ specimen/ object into sharper/ Sharpe focus  Stage - Platform where specimen (on slide) is placed. 6

16. K.C.S.E 2011 PP1 No.15 Give reasons for carrying out the following procedures when preparing temporary wet mounts of plant tissues.  Making thin plant sections - (To reduce layers of cells) to allow light to pass through  Adding water on the plant section- To make the cell turgid/ prevent drying up;  Placing a cover slip over the plant section - To protect lens on objective; exclude air/ dust/ foreign particles; Hold specimen in position/ place 17. K.C.S.E 2012 PP1 No.3 The figure below is a fine structure of a generalized animal cell as seen under an electron microscope. (a) Name the parts labeled A and B. (2mks)  A - Nucleopore; Accept. Nuclear pore. Reject pore in nucleus. Note: It must be a name, not a description  B - Rough endoplasmic reticulum; Reject endoplasmic reticulum attenae. (b) How is the structure labeled B adapted to its function? (2mks)  Surface covered with ribosomes; for protein synthesis;  Have interconnected channels; for transport of proteins;NB: Part (b) is tied to (a), reject if labeling of \"B\" in above is incorrect. Interconnected/owlet, and channels must be there to score; Feature tied to function 18. K.C.S.E 2012 PP1 No.12 (a)Name the part of a light microscope used to bring an image of a specimen into sharp focus. (I mark)  Fine adjustment knob; Rej fine adjusting knob/ adjustment knob alone/ coarse adjustment knob; 7

(b)Why is it recommended to keep the stage of the microscope dry? (1 mark)  Avoid refraction of light  Prevent melting of the slide; NB: Accept any one. Wrong answers negate the correct one: Rejects prevents rusting. 19. K.C.S.E 2012 PP1 No.30 Name the organelle that is involved in each of the following: (2 marks)  Manufacture of lipids - Smooth endoplasmic reticulum;  Formation of lysomes - Golgi bodies/ golgi body/ golgi apparatus; 20. KCSE 2013 PP1 NO 6 Using a microscope, a student counted 55 cells a cross a field of view whose diameter was 6000 micrometer. Calculate the average length of cells. Show your working. (2mks)  Length of cell = Diameter of the field of view o Total number of cell o = 6000 micrometer  55 o =109.09p,m 21. KCSE 2013 PP1 NO 9 State one way in which each of the following is structurally adapted to its functions:  (a)neurone; (2mks)  Neurone - has Schwann cells secretes the myelin sheath  Myelin insulates the axon (b) Mitochondrion. (2mks)  Mitochondria - interior membrane has in folding known as cristae to increase surface area for energy production.  Matrix contains enzyme for respiratory reaction 22. KCSE 2014 PP1 NO 7 A student drew a 6cm long diagram of a plant flower. If the actual length of the flower was 12cm, calculate the magnification of the drawing made by the student. Show your working. (2 mark)  Object length = 12 cm  Drawing length = 6 cm o Mg = Drawing length = 6  Object length 12  = X 0.5 8

23. KCSE 2014 PP1 NO 20 State one function of each of the following cell organelles: (a) Golgi bodies (1 mark)  Packaging of substances/glycoproteins/ transportation of glycoproteins;  Secretion of synthesized proteins and carbohydrates;  Formation of lysosomes/modifcation of carbohydrates to form glycoproteins; (b) Lysosomes. (1 mark)  Digestion of food/Breakdown large molecules;  Destroy worn out organelles or cells/tissue; 24. KCSE 2015 PP1 NO 5 (a) State two advantages of using a coverslip when preparing a specimen for observation under a light microscope. b) How is the low power objective lens manipulated to focus a specimen for observation under a light microscope? 9

3. CELL PHYSIOLOGY Specific Objectives - Meaning of cell physiology - Structure and properties of cell membrane (Theories of membrane structure not required) - Physiological processes - diffusion, osmosis and active transport - Factors affecting diffusion, osmosis and active transport - Role of diffusion, osmosis and active transport in living organisms - Water relations in plant and animal cells: turgor, plasmolysis, wilting and haemolysis Practical Activities - Diffusion as demonstrated with Potassium permanganate or potassium iodide/flower dyes/coloured plant extracts/smoke - Experiments with visking tubing and living tissues: fresh arrow roots/cassava/sweet potatoes/leaf petioles/irish potatoes/carrots - Plasmolysis can be demonstrated by using any of the following: spirogyra, epidermal cells of onion or raw egg that has been put in dilute hydrochloric acid overnight By the end of the topic, the learner should be able to: a) define cell physiology b) correlate the membrane structure with cell physiology in relation to permeability c) differentiate between diffusion, osmosis and active transport d) state and describe factors affecting diffusion, osmosis and active transport e) carry out experiments on diffusion and osmosis f) explain the roles of diffusion, osmosis and active transport in living organisms g) explain turgor and plasmolysis in terms of osmotic pressure. 10

1. K.C.S.E 1995 PP1 No.4 Explain what would happen to red blood cells if they are placed in a concentrated salt solution (2 marks)  Water in RBC moves out by osmosis and the RBC shrinks/crenates 2. K.C.S.E 1999 PP1 No.15 An experiment was carried out to investigate haemolysis of human red blood cells. The red blood cells were placed in different concentrations of sodium chloride solution. The percentage of haemolysed cells was determined. The results were as shown in the table below. Salt concentration 0.33 0.36 0.38 0.39 0.42 0.44 0.48 g/100cm3 (%) Red blood cells 100 91 82 69 30 15 0 Haemolysed (%) a) i) On the grid provided, plot a graph of harmolysed red blood cells against salt concentration. ii) At what concentration of salt solution was the proportion of haemolysed cells equal to non-haemolysed cells?  0.402; 0.403; 0.404; + 0.002 11

iii) State the percentage of cells haemolysed at salt concentration of 0.45%  9-10-11% b) Account for the results obtained at: 0.33 percent salt contration.  Less concentration // hypotonic // dilute than blood cells cytoplasm/ red blood cells; water is drawn in by osmosis the cells swells and eventually burst. 0.48 percent salt concentration.  Concentration of cytoplasm same as concentration of salt solution/isotonic; therefore no net movement of water; hence no haemolysis. (c)What would happen to the red blood cells if they were placed in 0.50 percent salt solution?  Percentage of cells haemolysed would still be zero Becomes turgid; due to the cell wall shrink/ crenate RBC would lose water by osmosis (d) Explain what would happen to onion epidermal cells if they were placed in distilled water.  The cells would absorb water due to osmosis, swell and become turgid.  The cell sap move conc. than surrounding water gate into the cell by osmosis; the cell swells/becomes turgid; but does not burst due to the cell wall 3. K.C.S.E 2000 PP1 No.7 Why is oxygen important in the process of active transport in cells? (I mark)  Oxygen is required for respiration that produces energy necessary for active transport e.g. oxidation of food for respiration 4. K.C.S.E 2004 PP1 No.16 a) What is diffusion (2marks)  The movement of molecules; from a region of high concentration to a region of low concentration; until the molecules are uniformly distributed in the medium) Acc. Particles for molecules; Rej substance for molecules b) How do the following factors affect the rate of diffusion? i) Diffusion gradient (1mk)  The higher diffusion gradient between (two points) the rate of diffusion; acc converse. ii) Surface area volume ratio (1mk)  The higher the surface area: Volume ratio, the faster is the rate of diffusion ; acc converse 12

iii)Temperature (1mk)  Increasing temperature increases the rate of diffusion; acc converse. (c)Outline three roles of active transport in the human body (3mks)  Re-absorption of glucose/ some salts in the kidney/ by kidney tubules;  Absorption of digested food/ from the alimentary canal  Re-absorption of useful material in the blood stream  Accept sodium pump mechanism in the nervous system, the nerve cell -Rej. Sodium pump mechanism alone. 5. K.C.S.E 2005 PP1 No.7 State the importance of osmosis in plants. (3mks)  Absorption of water from the soil by the roots  Support in seedlings, leaves and herbaceous plants.  Opening and closing of Stomata  Distribution of water from cell to cell  Feeding in insectivorous plants 6. K.C.S.E 2006 PP1 No.12 An experiment was set up in the experiment as show below The set up was left for 30 minutes. a) State the expected results. (1mk)  Visking tubing will become turgid; accept will increase in volume / bulges/ swells/ becomes bigger/ expands b) Explain your answer in (a) above (3mks)  Sucrose solution is hypertonic/ water is hypotonic; water moves from beaker into visking tube by osmosis though semi permeable visking tubing, making visking tubing turgid. Or water moves from beaker into visking tubing by osmosis, through semi permeable visking tubing; with hypertonic solution. 13

7. K.C.S.E 2007 PP1 No.5 Distinguish between diffusion and osmosis ( 2 marks) Diffusion Osmosis Involves movement of particles of Involves movements of solvent molecules of liquids or gas molecules It may be through a membrane or It takes place though a semi in air permeable membrane Not affected by PH changes Rate affected by PH changes 8. K.C.S.E 2008 PP1 No.4 The diagrams below show a red blood cell that was subjected to a certain treatment At start At the end of experiment (a) Account for shape of the cell at the end of the experiment (2 marks)  The red blood cell was placed in a hypertonic solution it lost water by osmosis/crenated (b) Draw a diagram to illustrate how a plant cell would appear if subjected to the same treatment (1 mark) o 14

9. K.C.S.E 2008 PP2 No.5 A freshly obtained dandelion stem measuring 5 cm long was split lengthwise to obtain two similar pieces. The pieces were placed in solutions of different concentrations in Petri dishes for 20 minutes. The appearance after 20 minutes is as shown a) Account for the appearance of the pieces in solutions L1 and L2 (6 marks)  L1 - Inner cells gained water by Osmosis; hence increased in length; epidermal cells did not gain water because they are covered by a water proof cuticle leading to curvature.  L2 - Inner cells lost water by osmosis; leading to (flaccidity) decrease in length; epidermal cells did not lose water due to waterproof leading to curvature b) State the significance of the biological process involved in the experiment ( 2 marks)  Absorption of water by the roots  Opening and closing of the stomata 10. K.C.S.E 2009 PP2 No.13 (a) Distinguish between diffusion and active transport ( 2 marks)  In diffusion ( Rej movement molecules) molecules move from a highly conc. Region to a lowly conc. Region while in active transport molecules move from a lowly concentration region to a highly concentration region; on diffusion molecules move along conc. gradient while in active transport molecules move against conc. gradient. No energy is required in diffusion while energy is required in active transport/ active requires carrier molecules while carrier molecule not required in diffusion. (b) State one role that is played by osmosis in (1 mark) (i) Plants  Absorption of water from the soil by root hair cells/ movement of water between plant cells/ from cell to cell/ opening one closing of stomata/ support in herbaceous plants due to turgidity / feeding in insectivorous plant. 15

(ii) Animals  Water reabsorption by blood capillaries from renal tubules/ absorption of water in colour dicututary/ canal/ gut movement of water from cell to cell in animals. 11. K.C.S.E 2010 PP1 No.7 Name the type of movement that occurs within a plant cell (1 mark)  Cytoplasmic streaming / Acc: cyclosis for cytoplasmic streaming 12. K.C.S.E 2009 PP1 No.15 Distinguish between haemolysis and plasmolysis. (2 marks)  Haemolysis – process by which red blood cells take in water till they burst; while Plasmolysis – loss of water from plant cells until the cell membrane is detached from the cell wall/ until the cell become flaccid. 13. K.C.S.E 2011 PP1 No.7 The diagrams below show an experiment set up to investigate a certain process in a plant tissue. o Explain the results obtained after 30 min.  Water was hypotonic to cell sap of adjacent cells and these cells absorbed water through osmosis; and their cell sap became less conc. than those of next cell; the process was repeated until water reached the sugar solution.  Sugar solution was hypotonic to cell sap of adjacent cells; they lost water by osmosis; cell sap became more conc. than those of next cell; the process was repeated until water was drawn from the beaker. 14. K.C.S.E 2012 PP1 No.4 In an investigation, a student extracted three pairs of pawpaw cylinders using a cork borer. The cylinders cut back to 50 mm length and placed in a beaker containing a solution. The results after 40 minutes were shown in the table below. (3 marks) 16

Feature Result Average length of cylinders (mm) 56 mm Stifflneess of cylinders stiff (a) Aoccount fo^r the results in the table above. (3 marks)  The solution was hypotonic/ less concentrated compared to cell sap of pawpaw cylinder cells. Accept the converse.  The tissue/ cells gained water by osmosis.  Reject if contradiction occurs in point I/ Note the sequential marking but proceed if proceeding point is not contradictory. Reject use of potato instead of pawpaw. (b) What would be a suitable control set-up for the investigation? (2 marks)  Pawpaw cylinders of same size/ length; placed in isotonic solution; Reject if same length or size and isotonic is missing.  Boiled pawpaw cylinders of same size/length; placed in similar solutions. Accept same/ hypotonic/ hypetonic solution in this case. Note: Osmosis must not occur in the control. 15. KCSE 2012 PP1.NO.13 State three factors that affect the rate of diffusion. (3 marks)  Temperature  Surface area;  Distance the particles have to travel/ thickness of the membrane. Accept thinness.  Diffusion/ concentration gradient;  Size/ density of molecules/ particles;  Medium of diffusion;  Surface area to volume ratio; reject ration for ratio; o Mark first three 16. KCSE 2013 PP1 NO 1  (a).What is meant by the term wilting? (1mk)  A process where cells of a herbaceous plant are plasmolysed, the stems droops and the leaves become limp. (b)Explain how increase in temperature affects the rate of active transport. (2mks)  Increase in temperature up to optimum activate the carrier proteins increasing rate of active transport very high temperature denatures the protein carrier reducing active transport. 17

17. KCSE 2013 PPI NO 2 The diagram below represents a cell as seen under an electron microscope (a) Based on the diagram, state whether it represents an animal cell or a plant cell (1 mark)  Animal cell (b)Give two reasons for your answer in 17(a) above.(2 arks)  lack of cell wall / have cell membrane only  have small vacuoles instead of large centralized one  nucleus is placed at the centre  presence of centrioles (c)Why is the palisade layer a tissue? (1 mark)  It has many cells of particular type grouped together to carry out the same  function as site for photosynthesis. 18. KCSE 2013 PPI NO 5 Describe how turgor pressure builds up. (3mks)  When plant cell are kept in in a hypotonic solution, cells gains water by osmosis, the vacuole swells exertion pressure on cell membrane against cell wall. 19. KCSE 2013 PP1 NO 30 (2mks) State two ways in which osmosis is significant to plants.  Turgidity enhances support in plant stems and leaves  Allows opening and closing of stomata.  Absorb water from the soil. 18

20. KCSE 2014 PP1 NO 5 The diagram below shows a set up for an experiment to demonstrate a certain physiological process.  a) What nature of solution is represented by 20% sugar solution? (1 mark)  Hypertonic solution (b) Explain the observation made on the set up after one hour. (2marks)  Volume of sugar solution increases in the (thistle funnel) distilled water in the beaker reduces; because the thistle / filter funnel gains distilled water by osmosis. 21. KCSE 2014 PP1 NO 10 (a) Explain two roles of diffusion in human beings. (4 mark)  absorption of materials e.g. diffusion of digested food into the blood stream;  Gaseous exchange e.g. CO2/O2 diffuses from capillaries into the alveoli.  excretion of nitrogenous wastes; e.g urea diffuses from blood capillaries into the elimination sites. b).What is meant by each of the following terms? Crenated cell. (1 mark)  Crenated cell is a shrunk animal cell that has lost water by osmosis Flaccid cell. (1 mark)  Flaccid cell is a flabby / shrunk plants cell that has lost water by osmosis 19

22. KCSE 2014 PP1 NO 26 The table provided shows the concentration of sodium and iodine in sea water and cell sap of a plant (a) (i)Name the process through which the plant cells take up sodium ions. (1 mark)  diffusion Give a reason for your answer in (a) (i) above. (1 mark)  Sea water contains a higher concentration of sodium ions than the cell sap; (b) If the plant was sprayed with a chemical that inhibits respiration: Which of the two ions uptake will be affected? (1 mark)  Iodide ions Give a reason for your answer in (b) (i) above. (1 mark)  Sea water has a lower concentration of iodide ions than the cell. o The plant requires energy to take up the iodide ions (by active transport); KCSE 2015 PP1 NO 6 Students set up an experiment as illustrated below. 20

(a)Name the physiological process that resulted in the observations made after 30 minutes.(1 mark) (b)State the importance of the physiological process investigated in plants.(1 mark) (c)Explain the observations made after 30 minutes. (2 marks) 21

4. (a) NUTRITION IN PLANTS Specific Objectives - Meaning, importance and types of nutrition - Nutrition in plants (autotrophism) - Definition of photosynthesis and its importance in nature - Adaptations of leaf to photosynthesis - Structure and function of chloroplast - Process of photosynthesis - light and dark stages (omit details of electron transport system and chemical details of carbon dioxide fixation) - Factors influencing photosynthesis - light intensity - carbon dioxide concentration - water - temperature - Chemical compounds which constitute living organisms - Chemical composition and functions of carbohydrates, proteins and lipids (omit details of chemical structure of these compounds and mineral salts in plant nutrition). - Properties and functions of enzymes (omit lock and key hypothesis) - Nutrition in Animals (heterotrophism) - Meaning and types of heterotrophism - Modes of feeding in animals - Dentition of a named carnivorous, herbivorous and omnivorous mammal - Adaptation of the three types of dentition to feeding - Internal structure of mammalian teeth - Common dental diseases, their causes and treatment - Digestive system and digestion in a mammal (human) - Digestive system, regions, glands and organs associated with digestion - Ingestion, digestion, absorption, assimilation and egestion - Importance of vitamins, mineral salts, roughage and water in human nutrition - Factors determining energy requirements in humans By the end of the two topics(NUTRITION IN PLANTS AND ANIMALS) 22 the learner should be able to: a) define nutrition and state its importance in living organisms b) differentiate various modes of feeding c) describe photosynthesis and show its importance in nature d) explain how the leaf is adapted to photosynthesis e) explain the factors affecting photosynthesis f) distinguish between carbohydrates proteins and lipids g) state the importance of various chemical compounds in plants and animals

h) explain the properties and functions of enzymes i) relate various types of teeth in mammals to their feeding habits j) differentiate between omnivorous, carnivorous and herbivorous modes of feeding k) relate the structures of the mammalian (human) alimentary canal to their functions i) explain the role of enzymes in digestion in a mammal (human) m) explain the factors that determine energy requirements in humans. Practical activities - Carry out experiments on factors affecting photosynthesis - Observe stomata distribution - Carry out food test experiments - Carry out experiments on factors affecting enzymatic activities - Investigate presence of enzymes in living tissues (plants and animals) - Observe, identify, draw and label different types of mammalian teeth - Carry out dissection of a small mammal to observe digestive system and associated organs (demonstration) 23

1. K.C.S.E 1995 PP1 No.5 State the role of light photosynthesis (2 marks)  Provide energy required for splitting water molecules/ photosynthesis. 2. K.C.S.E 1995 PP1 No.7 Complete the table below on mineral nutrition in plants (3 marks) Mineral element Function Deficiency symptoms - Synthesis of Stunted growth and proteins and yellowing of leaves protoplasm Calcium - Forms part of Yellowing of leaves chlorophyll Mineral element Function Deficiency symptoms Nitrogen Stunted growth and Synthesis of yellowing of leaves Calcium proteins and protoplasm Making cell walls Magnesium / mg Forms part of Yellowing of leaves chlorophyll 3. K.C.S.E 1996 PP1 No.7 (a) State the role of light in the process of photosynthesis (1 mark)  To split water/ Photosynthesis/photolysis (b) Name one end product of dark reaction in photosynthesis (1 mark)  Glucose/carbohydrate/ starch/ sugar 4. K.C.S.E 1998 PP1 No.2 State one effect of magnesium deficiency in green plants (1 mark)  Yellowing of leaves/stunted/ growth/chlorosis/ lack chlorophyll 24

5. K.C.S.E 1998 PP1 No.14 In an experiment to investigate a factor affecting photosynthesis, a leaf of a potted plant which had been kept in the dark overnight was covered with aluminum foil as shown in the diagram below  The set up was kept in sunlight for three hours after which a food test was carried out on the leaf. (a)Which factor was being investigated in the experiment?(1 mark)  Importance of light (b)What food test was carried out? (1 mark)  Test for starch (c)(i) State the results of the food test ( (2 marks)  The covered part of the leaf remain brown/yellow/ retain color of iodine, and the uncovered parts turned blue/ black; rej blue alone black alone. (ii) Account for the results in c (i) above (1 mark)  Starch was formed in the uncovered part of the leaf (because of the presence of light); while starch was not formed in the covered part of the leaf (because of lack light) (d)Why was it necessary to keep the plant in darkness; before the experiment? (2 marks)  To de-starch the leaf; OWETT 25

6. K.C.S.E 2001 PP1 No.12 The graph below shows the effect of substance concentration of the rate of enzyme reaction. (a)(i) Account for the shape of the graph between (i) A and B (2 marks)  More active sites of enzymes available, for a large number of molecules of substrate; hence increase in the rate of reaction (rapid of fast increase in the rate of reaction) (ii) B and C (2 marks)  Enzymes/ substrate are in equilibrium / all active sites are occupied; hence rate of reaction is constant (b) How can the rate of reaction be increased after point B? (1 mark)  Raising concentration of enzymes (c)State two other factors that affect the rate of reaction of enzyme reaction ( 2 marks)  PH, temperature, inhibitors/ cofactors 7. K.C.S.E 2003 PP1 No.9 Name the: (a)Material that strengthens xylem tissue.(1 mark)  Lignin b)Tissue that is removed when the bark of a dicotyledonous plant is ringed. (1 mark)  Phloem 8. K.C.S.E.2004 PP1 No.9 Name two mineral elements that are necessary in the synthesis of chlorophyll. (2 marks)  Nitrogen;  Magnesium;  Iron, acc. Magnesium ion/ iron rej symbols of elements 26

9. K.C.S.E 2005 PP1 No.2 The diagram below represents a cell. (a)Name the parts labeled X and Y (2mk)  X – Chloroplast  Y – Cell vacuole / sap vacuoles c) Suggest why the structures labeled X would be more on one side than the other. (1mk)  To receive optimum amount of light 10. K.C.S.E 2005 PP1 No.3 What is the role of the vascular bundles in plant nutrition? (3mks)  Xylem vessels transport water and mineral salts from the roots to the leaves.  Phloem tissues transport manufactured food/soluble Organic products of photosynthesis within the plant. 11. K.C.S.E 2006 PP1 No.1 a) State the functions of cristae in mitochondria. (1 mark)  To increase surface area for attachment of respiratory enzymes/ site for A.T.P formation/ site for energy production / site for respiration b) The diagram below represents a cell organelle. 27

(i)Name the part labeled Y. (1mk)  Stroma (ii)State the functions of the part labeled X. (1mk)  Bearing photosynthesis pigments/ chlorophyll/ site for light dependent reaction/ site for photolysis 12. K.C.S.E 2006 PP1 No.27 Name the end products of the light stage in photosynthesis. (2 marks)  Hydrogen  Oxygen  ATP 13. K.C.S.E 2007 PP1 No.6 Describe what happens during the light stage of photosynthesis (3 marks)  Take place in the grana of the chloroplast. Light is absorbed and used to split water molecules into hydrogen ions and oxygen, photolysis. Energy is formed and is stored in form of ATP 14. (K.C.S.E 2008 PP1 No.5 a) State two factors that affect enzymatic activities ( 2 marks)  Temperature PH co- factors, co- enzymes; enzyme product concentration; substance concentration/ metabolic poison b) Explain how one of the factors stated in (a) above affects enzymatic activities (1 mark)  Temperature- increase in temperature increases rate of enzymatic activity up to an optimum  low temperature decreases enzymatic activity/ too high temp above optimum point denatures enzymes.  Ph- Enzymes work best at optimum ph/extreme ph denatures enzymes.  Enzyme conc – Increase in conc. increase enzymatic activity.  Co- enzymes – complements enzymes increasing rate of activity  Substrate concentration increase enzymatic activity up to certain level. 28

15. K.C.S.E 2008 PP1 No.16 The diagram below represents a set up that was used to investigate certain process in a plant (a)State the process that was being investigated (1 mark)  Photosynthesis (b)State a factor that would affect the process (1 mark)  Carbon (IV) Oxide/ Temp/ chlorophyll (c) Give the identity of the gas produced (1 mark)  Oxygen 16. K.C.S.E 2008 PP1 No.18 How is the epidermis of a leaf of a green plant adapted to its function (2 marks)  Transparent to allow light to penetrate photosynthetic tissue/ single layer of cells/ thin to reduce distance over which light penetrate photosynthetic tissue; presence of stomata for gaseous exchange; closely fitting cells to protect inner tissues 17. K.C.S.E 2008 PP1 No.24 Name the sites where light and dark reactions of photosynthesis take place (2 marks)  Light reaction – Granum/ lamellae/ thylokoid  Dark reaction - Stroma 18. K.C.S.E 2008 PP2 No.3 The equation below represents a process that takes place in plants  6CO2 + 6H2O→C6H12O6 + 602 (a)Name the process (1 mark)  Photosynthesis 29

(b) State two conditions necessary for the process to take place (2 marks)  Light (energy)  Chlorophyll (c) State what happens to the end- products of the process (5 marks)  Oxygen – used in respiration, oxidation Released into the atmosphere  Glucose – used in respiration Converted to sucrose or starch for storage  Used in formation of cellulose cell wall/ cytoplasm 19. K.C.S.E 2009 PP1 No.18 Explain how the following factors affect the rate of photosynthesis: (a) Concentration of carbon (IV) oxide (1 mark)  Rate of photosynthesis increases as CO2 concentration increases up to a certain level/ optimum level and (vise versa) NB: Must mention up to optimum level or certain level (b) Light intensity (1mk)  Part of CO2 concentration. Acc: Reverse: The rate of photosynthesis decreases with decrease in CO2 concentration until it stop rate of photosynthesis increases as the light intensity up to an optimum level (and vice versa) 20. K.C.S.E 2010 PP1 No.9 State two ways in which chloroplasts are adapted to their functions. (2 marks)  Have grana that contains chlorophyll that absorb sunlight for photosynthesis  Grana is packed in form of thyrokoid discs that increase surface area for packaging of chlorophyll  Have gel-like substance,stroma that contains enzymes for the dark stage of photosynthesis. 30

21. K.C.S.E 2010 PP1 No.15 A potted plant was kept in the dark for 48 hours. Two leaves X and Y were treated as shown in the diagram below. The experimental set-up was kept in sunlight for 6 hours after which a starch test was carried out on the two leaves. (a)What were the results of the starch test on leaves X and Y? (2 marks)  X – Starch present  Y – Starch absent b) Give reasons for your answers in (a) above. (2 marks)  X – acts as a control; Y – CO2 absent absorbed by potassium hydroxide pellets; Acc correct explanation 22. K.C.S.E 2011 PP2 No.1 The set-up below illustrates a procedure that was carried out in the laboratory with a leaf plucked from a green plant that had been growing in sunlight. 31

(i) What was the purpose of the above procedure? (1mark)  Test a leaf for starch (ii)Give reasons for carrying out step A, B and C in this procedure. (3marks)  A – Kill the leaf or burst starch grains  B – To decolorize the leaf  C – To soften the leaf (iii) Name the reagent that was used at the step labeled D. (1mark)  Iodine solution (iv) State the expected result on the leaf after adding the reagent named in (iii) above. (1 mark)  Stain dark blue/ blue dark 23. K.C.S.E 2012 PP2 No.3a In an investigation, equal amounts of water was placed in three test tubes labeled G, H and J. Pondweeds of equal length were dropped in each test tube. The test tubes were then placed in identical conditions of light and carbon (IV) oxide at different temperatures for five minutes. After five minutes, the bubbles produced in each test tube were counted for one minute. The results were as shown in the table below. Test tube Temperature (°C) Number of bubbles G 20 28 H 35 42 J 55 10 (i) Name one requirement for this process that is not mentioned in the investigation. (1 mark)  Chlorophyll (ii) Name the gas produced in this investigation. (1 mark)  Oxygen (iii) Account for the results in test tubes H and J. (2 marks)  Test tube - H is at optimum temperature for enzyme activity; in test tube J most enzymes have been denatured by the high temperature; 24.(KCSE 2013 PP2 NO 3 a) Explain the importance of the following in photosynthesis: (3mks) (i) Light;  Light generates chemical energy which splits water to hydrogen Atoms and Oxygen gas. 32

(ii)Carbon (IV) oxide;  Carbon (iv) oxide reacts with hydrogen in the presence of enzymes to form simple sugars (iii) Chlorophyll  Chlorophyll traps /absorbs light energy from sunlight. 25. (KCSE 2014 PP2 NO 7(a) a) Explain how each of the following factors affects the rate of photosynthesis: (i) Temperature; (2 marks)  Reactions in photosynthesis are catalyzed by enzymes; at optimum temperature photosynthesis proceeds faster;  Below optimum temperature the rate of photosynthesis decreases because enzymes are inactivated by the low temperatures / above optimum the rate of photosynthesis decreases because enzyme are denatured / destroyed (ii) Chlorophyll concentration. (2 marks)  Chlorophyll traps energy from (sun) light for photosynthesis. The higher the chlorophyll concentration the higher the rate of photosynthesis. 33

26. (KCSE 2015 PP2 NO.4 In an experiment to investigate a factor affecting photosynthesis, a potted plant which had been kept in the dark overnight was treated as shown in the diagram below and exposed to light. (a)Why was the potted plant kept in the dark overnight?(1 mark (b)Which factor was being investigated in the experiment?(1 mark) (c) (i)Which test did the students perform to confirm photosynthesis in the leaves labelled P and Q? (1 mark) (ii)State the results obtained in the leaves labelled P and Q. P Q (1 mark) (iii)Explain the results obtained in the leaves labelled P and Q. (1 mark) (d) What was the purpose of leaf Q in the experiment?(1 mark) 34

4. (b) NUTRITION IN ANIMALS 1. K.C.S.E 1995 PP1 No.10 An experiment was carried out to investigate the rate of reaction shown below Sucrose →Fructose + Glucose For the products fructose and glucose to be formed, it was found that substance K was to be added and the temperature maintained at 370C. When another substance L was added, the reaction slowed down and eventually stopped. (a) Suggest the identify of substances K and L (2 marks)  K-Enzymes/ Sucrose/ Invertase/ Saccharise  L- Inhibitor Acceptance any example e.g. any acid (b) Other than temperature state three ways by which the rate of reaction could be increased (3 marks)  Addition of sucrose/ substrate  Optimum/ suitable/ correct / right pH  Removal of products (c) Explain how substance L slowed down the reaction (2 marks)  By blocking the active sites of the enzymes 2. K.C.S.E 1996 PP1 No.3 When is glycogen which is stored in the liver converted into glucose and released into the blood (1 mark)  After vigorous activity when blood sugar fall below normal 3. K.C.S.E 1996 PP1 No.3 Name the disease in humans that is caused by lack of vitamin C (1 mark)  Scurvy 4. K.C.S.E 1997 PP1 No.10 Name a disease caused by lack of each of the following in human diet .(2 marks)  Vitamin D - Rickets/Osteoporosis  Iodine – Goitre 5. K.C.S.E 1997 PP1 No.20 (a) What is meant by the term digestion? (2 marks)  Breakdown of (complex) food substances by enzymes; to simpler compounds (which can be absorbed) 35

(b) Describe how the mammalian small intestine is adapted to its function (18 marks)  Small intestines are long/coiled: to offer large surface area for digestion and absorption:  The walls are muscular: for peristalsis  Inner walls posses mucus glands/ accept goblet cells that secrets mucus; for lubrication; and protection of wall from digestive enzymes:  The inner walls have digestive glands: that secret (digestive) enzymes:  The inner walls have villi: to increase surface area for absorption/ diffusion; accept ‘epithelium is one cell thick’  The villi have numerous blood vessels: for transport of the end products of digestion; accept at least two correctly named examples/ end products of glucose amino acids/ mineral salts vitamins.  The villi also have vessels for transport of fats/lipids o NB: Accept illustrations of cell are thick epithelium 6. K.C.S.E 1998 PP1 No.18 A hungry person had a meal, after which the concentration of glucose and amino acids in the blood were determined. This was measured hourly as the blood passed through the hepatic portal vein and the iliac vein in the leg. The results were as shown in the table below. Time Concentration of Concentration of (hrs) contents in hepatic contents in the iliac portal vein (mg/100ml) vein of the leg 0 (mg/100ml) 1 Glucose Amino acids 2 85 10 Glucose Amino Acids 3 85 1.0 4 140 1.0 85 1.0 5 130 1.5 85 1.0 6 110 1.5 125 1.0 7 90 3.0 110 1.5 90 2.0 90 3.0 90 1.0 90 2.0 90 1.0 90 1.0 36

a) Using the same axes draw graphs of concentration of glucose in the hepatic portal vein and the iliac vein in the leg against time (7 marks)  If axes reversed allow marks for identification of curves only max 2 o Correct scales – 2 marks o Correctly labeled axes – 2 marks o Scale – 2 marks o Smooth curve – 1 mark (b) Account for the concentration of glucose in the hepatic vein from: (i) 0-1 hour (2 mark)  Acc constant/low/below normal levels in blood; No/little digested foods/glucose from the intestines/gut/alimentary canal/absorption. (ii) 1-2 hour (3 marks)  Sharp increase in concentration of glucose in blood; (more) absorption of glucose; after digestion of the meal. (iii) 2- 4 hours (3 marks)  Glucose concentration declining/decreasing; less glucose being absorbed; (more) glucose being converted to glycogen in the liver/tissue/used for (tissue) respiration. (iv) 5 – 7 hours (2 marks)  Concentration of glucose stabilizes/constant/ this is the normal glucose level concentration in the blood. 37

c) Account for the difference in the concentration of glucose in hepatic portal vein and the iliac vein between 2 and 4 hours. (2 marks)  The concentration of glucose in the iliac vein is lower than in the hepatic portal vein; Glucose in hepatic portal vein is not regulated by the liver. Glucose that leaves the liver to iliac vein is regulated. d) Using the data provided in the table explain why the concentration of amino acids in the hepatic portal vein took longer to increase.(1 mark)  Proteins take longer to digest. 7. K.C.S.E 1998 PP1 No.20 Explain how the mammalian intestines are adapted to perform their function. (20 marks)  The mammalian intestines are relatively long/coiled/folded. This allows food enough (enough) lime/increases surface area for digestion and absorption of products of digestion. The intestinal surface area for absorption.  The glands have enzymes which secrete enzymes for digesting e.g. of correct enzyme, maltase, sucrase, lactase, enterokinase and peptidases.  Some glands/goblets cells also produce mucus which protects the intestinal wall from being digested, reduce friction.  Intestines have opening of ducts which allows bile/pancreatic juice into the lumen.  The intestines have circular and longitudinal muscles whose contraction/relaxation/peristalis leads to the mixing of food with acc. At least enzymes/juices facilitating rapid digestion and helps pus food along the gut.  Intestines are well supplied with blood vessels to supply oxygen/remove digested food.  Presence of lacteal vessels for transport of fats/lipids.  Have thin epithelia to facilitate fast/rapid absorption/diffusion. Allow increase in surface area for absorption only. 8. K.C.S.E 2001 PP1 No.5 State two functions of muscles found in the alimentary canal of mammals (2 marks)  Act as valves for regulations of food movement/ to close or open various parts of the canal.  Churning (acc. mixing food with enzymes) pushing food along peristals 38

9. K.C.S.E 2001 PP1 No.16 An experiment was carried out to investigate the nutritional value of two dry powder animals feeds X and Y over a period of six months. Twenty 5 month’s old castrated goats were used. The goats were divided into two equal groups A and B. The animal’s in group A were fed on feed X throughout the experiment while those of group B were fed on feed Y. The feeds were supplemented with dry hay and water. The average body weight of each group of goats and the weight of the dry powder feeds were determined and recorded each month. The faeces produced by each group was dried and weighed and the average dry faecal output per month was also recorded. The results are as shown below. GROUP A GROUP B Months since Averag Average Average Average Average Average commencement e total weight monthly total weight monthly of the weight of total dry weight of of total dry experiment of feed.(kg) faecal goats(kg) feed faecal goats output (kg) output ( kg) (kg) ( kg) 0 20.4 26.7 10.5 20.5 35.4 16.5 1 22.5 27.5 10.7 19.5 34.3 17.7 2 24.5 25.8 10.3 19.0 35.2 17.2 3 26.3 18.5 8.8 18.5 36.1 17.5 4 28.0 16.6 7.2 17.1 36.0 16.9 5 29.4 16.3 6.0 16.3 35.8 16.8 6 29.5 16.1 5.6 15.6 35.5 16.6 (i)What is the relationship between the amount of feed and the faecal output (2 marks)  The more the feed the more the feacal output  The less the feed the less the faecal output (ii) Work out the average increase in weight for the animal’s in group A during (2 marks) The first four months The last two months The first four months 2.1 + 2.0 + 1.8 + 1.7 =1.9 kg OR 28.0 – 20.4 =1.9kg 4 4 The last two months 29.5 – 28.0 = 0.75kg 2 14 + 0.1 = 0.75kg OR 2 (iii)Account for the average increase weight in goats in group A 39 during the first four months First four months  Fast/ rapid/Active growth hence increase in weight

The last two months  Slow growth, reached maturity (iv). Which of the two feeds is more nutritious? Give reason for your answer  Feed X  Group A gained (more) weight, on less food while group B lost weight on more food. (b)State four uses of digested food in the bodies of animals  Growth, repair, protection, energy production (c)State four uses of water in the bodies of animals  A solvent, transport medium. Hydrolyses of food, maintenance of temperature. 10. K.C.S.E 2002 PP1 No.3 a) State the function for co-factors in cell metabolism  Substances that activate enzymes b) Give one example of a metallic co – factor  Metallic ions e.g. iron / mg / Zn / Cu / (accept correct iron forms) o Fe 2+, Mg2+, Ca2+, Mn2+, Co2+ , Kl, mo2+, (Reject wrong charges). 11. K.C.S.E 2002 PP1 No.10 What happens to excess fatty acids and glycerol in the body?  Converted into fatty acids and stored beneath skin (adipose tissue) 12. K.C.S.E 2003 PP1 No.8 State a function of the large intestine in humans  Absorption of water; accept absorption of salts / calcium / iron; secretion of mucus 13. K.C.S.E 2006 PP1 No.8 State the role of vitamin C in humans. (2mks)  Prevents scurvy/ prevent bleeding of gums/ hence healthy gums, Prevents poor healing of wounds/ prevent degeneration of muscle and cartilages/ prevent red spot on skin/ prevent anemia  Excretion absorption of iron  Enables absorption of iron  Boost immunity  Development of healthy gums  Synthesis/ maintenance of collagen fibres/ connective 40

14. K.C.S.E 2006 PP1 No.17 (1mk) a) Distinguish between the terms homodont and heterodont.  Homodont – having same kind/ type/ similar teeth.  Heterodont – having different type kind of teeth b) What is the function of carnassials teeth? (1mk)  Cutting/ chopping/ Shearing/ Slicing/ crusting c) A certain animal has no incisors, no canines, 6 premolars and 6 Molars in its upper jaw. In the lower jaw there are 6 incisors, 2 canines, Premolars and six molars. Write its dental formula o i 0 C 0 PM 3 M 3 o3 1 33 15. K.C.S.E 2006 PP1 No.18 a) State two functions of bile juice in the digestion of food. (2mks)  Emulsification of fats/ breaking into small droplets; Increase surface area for digestion;  Neutralizes acidity of chime/ provides alkaline media for enzyme action. b) How does substrate concentration affect the rate of enzyme action? (1mk)  Increase in substrate concentration rise enzyme action up to a certain point and further rise of substrate will have no effect. 16. K.C.S.E 2007 PP1 No.7 The diagram below represents a section though a human tooth (a) (i) Name the type of tooth shown (1 mark)  Pre- molar tooth (ii)Give a reason for your answer in (a) (i) above (1 mark)  Presence of two roots 41  Presence of cusps of the crown

(b) State the functions of the structures found in part labeled J (2 marks)  Has nerve cells that increase sensitivity of the tooth to heat and pain  Has a blood vessel that provides nourishment to the tooth and remove waste products 17. K.C.S.E 2007 PP1 No.8 (a) Name a fat soluble vitamin manufactured by the human body (1 mark)  Vitamin D  Vitamin K (b) State two functions of potassium in the human body (2 marks)  Transmission of nerve impulses  Ionic balance/ osmotic balance  Contraction of muscles 18. K.C.S.E 2007 PP1 No.25 (a)The action of ptyalin stops at the stomach. Explain (1 mark)  Works well in neutral PH but stomach is acidic (b) State a factor that denatures enzymes (1 mark)  Temperature above optimum (c)Name the features that increase the surface area of small intestines (2 marks)  Long  Highly coiled  Numerous villi and microvilli 19. K.C.S.E 2008 PP1 No.23 (2 marks) The diagram below shows a human tooth (a) Identify the tooth (1 mark)  Canine 42

(b) How is the tooth adapted to its function (1 mark)  Pointed/ sharp for piercing/ tearing/ cutting food (c)State the role of the following vitamins in the human body (2 marks)  C- Absorption of lien/ prevent scurvy/ quick healing of wounds/ best immunity/ ant oxidants/ prevents anaemia/ formation of connective tissues  K – blood clothing 20. K.C.S.E 2009 PP1 No.22 Explain how the carnassials teeth of a dog are adapted to their function (2 marks)  Large/ powerful for cracking/ breaking/ crushing bone/ slide past each other/ scissor- like for shearing/ cutting/ slicing (off) flesh/ tendons/ skin from bone 21. K.C.S.E 2009 PP1 No.23 State the function of iron in the human body.  A component of haemoglobin or formation of haemoglobin 22. K.C.S.E 2009 PP1 No.24 Explain how the following factors determine the daily energy requirement in human: (a)Age (1 mark)  Young people are actively/ rapidly growing hence requires more energy than older people for cell division. (b)Occupation (1 mark)  Manual workers require more energy equivalent to work done than sedentary workers (c)Sex (1 mark)  Males are more muscular hence require more energy than females to maintain every cell. 43

23. K.C.S.E 2009 PP2 No.2 The diagram below represents the lower jaw of a mammal (a) Name the mode of nutrition of the mammal whose jaw is shown (1 mark)  Herbivorous Rej Herbivore Acc Herbivory (b)State one structural and one functional difference between the teeth labeled J and L Structural (1 mark)  Tooth J is narrow/ sharp/ chisel like while tooth L is broad/ ridged Accept: J has one root while L has 2/3/4 roots (c) Functional (1 mark)  Tooth J is used for cutting while tooth L is used for grinding  (Acc cutting for biting) (i) name the toothless gap labeled K. (1 mark)  Diastema (ii)State the function of the gap.  To allow manipulation of food by tongue, separating chewed and newly cut vegetation. (d) Name the substance that is responsible for hardening of teeth (1 mark)  Calcium phosphate; Rj calcium/ phosphorous/ phosphate 44

24. K.C.S.E 2009 PP2 No.6 An experiment was carried out to investigate the effect of temperature on the rate of reaction catalyzed by an enzyme. The results are shown in the table below Temperature (oC) Rate of reaction in mg of products per unit time 5 10 0.2 15 20 0.5 25 0.8 30 35 1.1 40 1.5 45 2.1 50 55 3.0 60 3.7 3.4 2.8 2.1 1.1 (a) On the grid provided draw a graph of rate of reaction against temperature (6 marks) (b) When was the rate of reaction 2.6 mg of product per unit time? (2 marks)  330C and 51.5 (± 0.50C)  32.5 - 33.5 and 51.0 – 52.0 45

(c) Account for the shape of the graph between (i) 50 C and 400 C ( 2 marks)  As temperature is increased rate of reaction is increased/ more products are formed (per unit time) because enzymes become more active (ii) 45o C and 60o (3 marks)  As temperatures increases rate of reaction decreases less products are formed (unit per time) because enzymes become denatured by high temperatures above 400, hence cannot act on substrate. (d) Other than temperature name two ways in which the rate of reaction between 50C and 400C could be increased (2 marks)  Increase in enzyme and substance concentration  Use of cofactors and co-enxymes (e) (i) Name one digestive enzymes in the human body which works best in acidic condition (1 mark)  Pepsin,  Chymosin  Renin (ii) How is the acidic condition for the enzyme named in (e) (i) above attained? (2 marks)  Wall of stomach/ gastric gland/ oxyntic/ pariental/ cell produced Hydrochloric (f) The acidic conditions in (e) (ii) above is later neutralized (i) Where does the neutralization take place?  Duodenum (ii) Name the substance responsible for neutralization (1 mark)  Bile juice/ SANS any correct salt e.g. NaHCO3  Acc: Bile 25. K.C.S.E 2010 PP2 No.16 What is the role of bile salts in humans? (2 marks)  Emulsification / breaking down of fats into (tiny) droplets  Creating alkaline medium for digestive enzymes/ neutralizing acidic chyone (from the stomach) 26. K.C.S.E 2010 PP2 No.17 The following is the dental formula of a certain mammal: i 0 c 0 pm 3 m 3 31 33 46

(a)State the likely mode of feeding for the mammal. (1 mark)  Herbivorous; Rej Herbivores (b)Give a reason for your answer in (a) above. (1 mark)  Lack canines/ incisors on upper jaws 27. K.C.S.E 2011 PP1 No.2 (a) Write the dental formula of an adult human. o i 2/2 C1/1 pm 2/2 m 3/3 or 2(i 2/2 C 1/1 pm 2/2 m 3/3) = 32 (b) Name two dental diseases  Dental carries;  periodenties/ periodontal disease/ pyorihoea 28. K.C.S.E 2011 PP1 No.13 State two functions of carbohydrates in the human body  Source of energy  Storage of materials 29. K.C.S.E 2011 PP1 No.17 The diagram represents part of the human digestive system.  (a)(i)Name the organs labeled L and M.  L – Duodenum  M – Pancrease b (i) Name the substance produced by the organ labeled K  bile (ii) State the function of the substance named in b (i) above  Emulsification of fats; neutralize acidic chyme from stomach; provides alkaline medium for enzymes to work best. 47

30. K.C.S.E 2011 PP1 No.18 (a) Name one salivary gland in human  Sublingual; sublmaxillary/ submandibular; parotid (b) State two functions of saliva  Lubricating food; Digestion of starch; Moistens food; Provides alkaline medium;  Soften food; Dissolves food. Acc. For correct component of saliva to correct function 31. K.C.S.E 2012 PP1 No.29 Name two nutrients that are absorbed without being digested by enzymes in humans. (2 marks)  Water  Mineral salts  Vitamins: 32. K.C.S.E 2012 PP2 No.3 (b) State two ways in which the human intestinal villus is adapted to its function. (4marks)  The villus epithelium is thorny; for faster diffusion/ dissolved/ soluble/ digested food substances/ nutrients/ A. A/ glucose/ vitamins;  The epithelium has goblet cells; which secrets mucus lubricate food helping its passage/ prevent digestion of wall by enzymes;  They have microvilli; which increases their S.A for absorption dissolved/ soluble/ digested food substances/ nutrients/A.A/ vitamins/ g/  Has lacteals; for absorption of fatty acids & glycerol transport lipids; Highly vascularised;  For absorption / transport of digested food substances; have penes cells to produce lysozymes which are antibacterial.  Has crypts of lieberkuhn; which produce intestinal in which-contain digestive enzymes. 33. KCSE 2013 PPI NO 4 (2mks) (a)State two roles of mucus in the stomach  Lubricates the stomach lining/wall  Reduces auto digestion  (b)Explain how age determines a person’s energy requirement. (2mks)  Young people are actively growing; requires a higher amount of energy as compared to older people whose rate of cell division is slower. 48

34. K.C.S.E PP2 2013 NO 3 (a) Name one appropriate food substance for each of the following enzymes: (2mks) (i) Ptyalin  Ptyalin digest starch to maltose  (ii) Pepsin.  Pepsin acts on proteins to peptides (b)State the cause and two symptom of Beri-beri Cause (1mk)  lack of vitamin B1or Thiamine Symptoms (2mks)  gastro intestinal disturbances  Muscles weakness  Wasting Paralysesis 35. KCSE PP2 2014 NO 7(b) Describe the process of carbohydrate digestion in human beings. (16 marks)  Food is chewed to increase the surface area for enzyme activity (saliva contain) salivary amylase / ptyalin, saliva (mixes with food and ) provides an alkaline medium.For amylase enzymes / ptyalin Salivary amylase acts on starch // amylase and converts them to maltose  In the duodenum; food is mixed with bile and pancreatic juice  Bile provides alkaline medium for activity of duodenum / enzymes and neutralizes acidic chyme / food from the stomach;  Ace. Sodium hydrogen carbonate for bile rej. Sodium bicarbonate  Pancreatic juice contain) pancreatic amylase; which converts starch to maltose;  In the ileum; epithelial cell s ileum secretes succusentericus / intestinal juice which contain enzymes.  This acts on sucrose and converts it to fructose and glucose;  Lactase; which acts on lactose and converts it to galactose and glucose; maltase acts on maltose and converts it to glucose 36. KCSE PP2 2015 NO.17 (a) How is a human stomach adapted to (i) protein digestion?(2 marks) (ii) churning? (2 marks) (b)What happens to the glucose synthesized during photosynthesis? (2 marks) 49

FORM 2 5. (a)TRANSPORT IN PLANTS Specific Objectives - Meaning and importance of transport systems - Absorption of Water and Mineral Salts - Internal structure of root and root hairs - Absorption of water - Active uptake of mineral salts - Transpiration - Definition of transpiration - Review of the structure of the leaf - Structure and function of xylem - Factors affecting transpiration - Forces involved in water movement in plants - Transpiration pull - Cohesion and adhesion - Capillarity - Root pressure - Translocation - Structure and function of phloem - Materials translocated (omit mechanisms of translocation) - Comparison between open and closed circulatory system - Mammalian Circulatory System - Structure and function of the heart, arteries, veins, and capillaries - Diseases and defects of the circulatory system (Thrombosis, Varicose veins, Arterio-sclerosis) and how to control them. - The Structure and Functions of Blood - Composition of blood - Functions of blood plasma - The structure and functions of ed blood cells and white blood - Mechanism of blood clotting and its importance - Blood groups (ABO system and the Rhesus factor) - 9 Immune responses - Natural and artificial immunity - Allergic reactions - Importance of vaccinations against diseases (Tuberculosis, Poliomyletis, Measles, Diphtheria, Whooping cough) Practical Activities - Observe permanent slides of sections of stems and roots - Carry out experiments to compare transpiration on lower and upper leaf surfaces - Observe wall charts/models - Analyse data on transpiration rate under different environmental conditions in Plants 50

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