BIOLOGY 2016.pdf 1

- Dissect a small mammal and observe its transport system (demonstration) - Make a longitudinal section of the mammalian heart to display the chambers and associated blood vessels - Record pulse rate at the wrist before and after vigorous activities and analyse the results - Demonstrate the unidirectional flow of blood in the cutaneous veins of the fore arm By the end of the two topics that follow,( TRANSPORT IN PLANTS AND ANIMALS) the learner should be able to: a) define transport and explain the necessity of transport in plants and animals b) relate the structure of the root, root hair, xylem and phloem to their functions c) relate the internal structure of the leaf to transpiration d) explain possible forces involved in the movement of water and mineral salts through the plant e) explain the significance of and factors affecting transpiration f) demonstrate simple experiments on transpiration g) distinguish between closed and open circulatory systems h) relate the structure of the heart and the blood vessels to their functions i) trace the path taken by blood from the heart to all parts of the body, and back to the heart j) name the common diseases of the circulatory system in humans and suggest methods of control / prevention k) relate the structure of the components of blood to their functions I) explain how oxygen and carbon dioxide are transported in the blood m) describe the mechanism of blood clotting and its importance n) describe the human blood groups and their importance in blood transfusion o) explain immunity and describe immune responses. 51

1. K.C.S.E 1995 PP1 No. 11 The diagram below represents a transverse section of a young stem (2 marks) (a)Name the parts labeled A and B  A – Epidermis  B – Pith (b)State the functions of the parts labeled C, D and E ( 4 marks)  C – Transport manufactured food / translation; Rej. Digested food  D – Produces new cells/ divides to give new cells. Accept secondary thickening/ growth/ produces phloem & xylem.  E- Transport minerals salts/ minerals/ salts alone (c)List three differences between the section shown above and one that would be obtained from the root of the same plant ( 3 marks)  Xylem in central/ Star shaped  Phloem in arms of xylem  Root hairs present in root / has pilferous layer  No pith in root 2. K.C.S.E 1996 PP1 No. 14(b) Name two structures used for gaseous exchange in plants (2 marks)  Stomata  Lenticels 3. K.C.S.E 1996 PP1 No.19 The diagram below represents the pathways of water from the soil into the plant.  52

(a)Name the structures labeled K and L. (2 marks)  K- Root hair  L- Xylem vessel (b)Explain how water from the soil reaches the structure labeled L. (5 marks)  Water moves from the soil into the root hair by osmosis; because  Concentration of cell sap is higher than water in the soil; the cell sap in the root hair is diluted, thus making it less concentrated than neighboring cell; therefore water moves into the neighboring cell; it is actively secreted into structure L. (c)Name the process by which mineral salts enter into the plant (1 mark)  Active transport/ diffusion 4. K.C.S.E 1997 PP1 No.4 State two ways in which xylem vessels are adapted to their function  Lignified thickened to prevent collapsing (Acc. Strengthened add strength)  Narrow to facilitate capillary:  Hollow for continuous flow of water 5. K.C.S.E 1997 PP1 No.13 An experiment was carried out to determine the rate of transpiration in three plants a, B and C. Plants, A and B belonged to different species while plants B and C belonged to the same species. Plant C had all its leaves removed. The three plants were of similar size and were exposed to the same environment conditions. The results are as shown below in the graphs below o 53

(a) Suggest possible environment conditions under which the experiment was carried out between 30 and 60 minutes  Strong air/ winds  High temperature  Low humidity; accept dry conditions/ sunlight (b)Account for the results obtained for plant C  Absence of leaves/ stomata absent  Transpiration; / little transpiration (c)Suggest the habitat for plant A and B. Give reasons for your answer.  Habitat for plant A is an arid/dry/ desert/ accept semi- desert. Reason being the low rate of water loss therefore presence of adaptations for water conservation  Habitat for plant B is a wet/moist/aquatic. Reason being high rate of water/ high rate of transpiration /acc. A lot of water loss 6. K.C.S.E 1999 PP1 No.1 Name two processes that bring about the translocation of manufactured food  Active transport  Diffusion  Mass flow  Cytoplasmic streaming 7. K.C.S.E 2002 PP1 No.16 The diagram below represents part of phloem tissue.  (a)Name the structures labeled R and S and the cell labeled T.  R. Sieve pore  S- cytoplasmic strand, cytoplasmic filaments rej. Proto plasmic strand)  T – Companion cell (b)State the function of the structure labeled S  Translocation (L is tied with structures) 54

(c)Explain why xylem is a mechanical tissue  Thickened and lignified. 8. K.C.S.E 2003 PP1 No.7 The diagram below represents regions of a root tip. (a)Name the tow regions above X in ascending order  Zone of cell division Acc cell multiplication  Zone of cell elongation / enlargement; Acc expansion for elongation b) State the function of the part labeled X  To protect root tip 9. K.C.S.E 2005 PP1 No.14 A set up that was used to investigate certain process in plants is shown in the diagram below.  (1mk) a) What process was being investigated?  Transpiration 55

b (i)State two precautions that should be taken when setting up the experiment.(2 marks)  The leafy shoot should be from herbaceous plant  Cut off the last few centimeters of the stalk under water  All the air in the capillary tubule should be expelled  Jelly should be applied around the stem around the rubber bung.  The end of the capillary tubing should rest in beaker of water. ii) Give a reason for each precaution stated in b (i) above. (2mks)  Avoid air bubbles.  For continuity of the flow of water  Jelly should not touch the xylem vessels because it might block the xylem and make the rubber bung air tight..  To avoid introduction of air bubbles in the xylem.  For continuity of water uptake. c) State three environmental factors that influence the process under investigation. (3mks)  Temperature  Humidity  Wind  Atmospheric pressure  Light intensity  Availability of water 10. K.C.S.E 2006 PP2 No.4 The diagram below represents a traverse section through a plant organ  a).From which plant organ was the section obtained?(1 mark)  Root b).Give two reasons for your answer in (a) above. (2mks)  Presence of root hairs  Presence of endodermis  Xylem star shaped at centre  Phloem at arms of the xylem 56

c).Name the parts labeled J, K and L. (3mks)  J- Epidermis  K- Phloem  L – Xylem d).State two functions of the part labeled M.(2mks)  Absorption of water  Absorption of minerals salts 11. K.C.S.E 2006 PP2 No.8 Describe how water moves from the soil to the leaves in a tree. (20mks)  Water exists as a thin film in the soil between soil particles. The concentration cell sap is greater than that of the surrounding solution in the soil; thus drawing water molecules across the cell wall and membrane into the root hair cells; by osmosis; water drawn into the root hair cell dilutes the cell sap/ makes it less concentration than that in the adjacent cell into the cortex cells. (By osmosis); across the endosperm by active transport; into the xylem vessels (of the root); Then conduct the water up into the xylem (vessels) of the stem; into xylem of leaves. Water is pushed/ rises up the stem by root pressure (in the xylem vessels) water would rise by capillary; cohesion, and adhesive forces; water moves as a continuous an uninterrupted water column in the xylem (vessel) up the tree to the leaves. As water vaporizes from the spongy mesophyll cells; their cells sap becomes more concentrated than adjacent water flows into the cells from other surroundings cells; which in turn takes in water from xylem vessels within the leaf veins. This creates a pull / suction force/ transpiration pull that pulls a stream of water from xylem vessel in the stem and roots; the transpiration pull maintains continuous column of water from the roots into the leaves (transpiration stream). 12. K.C.S.E 2007 PP1 No.9 State two ways in which the root hairs are adapted to their function (2 marks)  Absence of cuticle to allow diffusion of water  Thin walled to reduce distance of diffusion  Elongated to increase surface area for absorption of water and mineral salts  Presence of large vacuole to increase concentration gradient between cell sap and soil water 57

13. K.C.S.E 2007 PP1 No.9 The diagram below represents a plant tissue (a) Name the tissue (1 mark)  Phloem tissues (b) Name the cells labeled K and L. (2 marks)  K- Companion cell  L – Sieve tube (c) What is the function of the companion cell? (1 mark)  Supply nutrients and energy to the sieve tubes 14. K.C.S.E 2008 PP1 No.1 Name the tissues in plants responsible for: ( 3 marks) (a) Transport of water and mineral salts- xylem  Xylem (b)Transport of carbohydrates- Phloem  Pholoem tissues (c) Primary growth - Apical meristems  Apical meristems 58

15. K.C.S.E 2008 PP2 No.6 An experiment was carried out to investigate transpiration and absorption of water in sunflower plants in their natural environment with adequate supply of water. The account of water was determined in two hour intervals. The results are as shown in the table below Time of day Amounts of water in grammes 11 00 - 13 Transpiration Absorption 00 13 00 - 15 33 20 00 15 00 - 17 45 30 00 17 00 - 19 52 42 00 19 00 - 21 46 46 00 21 00 - 23 25 32 00 23 00 - 01 16 20 00 01 00 - 03 08 15 00 04 11 59

(a)Using the same axes, plot graphs to show transpiration and absorption of water in grammes against time of the day (7 marks) o (b)At what time of the day was the amount of water the same for transpiration and absorption? (1 mark)  17.001- 19.99 hrs (c)Account for the shape of graph of: (i)Transpiration (3 marks)  1100 – 17000 (rapid) (in the rate of transpiration) due to high light intensity/ high temperature  17000 – 0300 hrs decrease (in the rate of transpiration) due to low light intensity/ absence of light/ in temperature. (ii)Absorption (3 marks)  11.00 – 1900 hrs. Increase (in the rate of atmosphere) of water to replace water lost- through transpiration.  1900 – 0300 hrs; decrease (in the rate of absorption of water) due to the fact that rate of transpiration has declined (d)What would happen to transpiration and absorption of water if the experiment was continued till 05 00 hours? (2 marks)  Both transpiration and absorption decrease 60

(e) Name two factors that may affect transpiration and absorption at any given time (2 marks)  Wind; light, atmosphere pressure, humidity; temperature  Temperature - at high temperature the rate is higher/ at low temperature the rate is low (f)Explain how the factors you named in (e) above affect transpiration (2 marks)  Wind- rate of transpiration is high when it’s windy/ lower when air still  Humidity – when humidity is low, the rate of transpiration is faster/ when its High the rate of transportation is low  Pressure- the rate is high at low atmosphere pressure at high atmosphere pressure the rate is low. 16. K.C.S.E 2009 PP1 No.6 The diagram below shows a section through a plant organ o (a)(i) Name the class of the plant which the section was obtained (1 mark)  Dicotyledonae; Rej: Dicotyledonous (ii) Give a reason for your answer in (a) (i) above  Vascular bundles arranged in a ring / presence of vascular. Rej pith- not visible also found in the root of monocots. Rej intra vascular bundle (b) State the functions of the part labeled F (1 mark)  Divides to) give rise to secondary thickening (growth/ increase in growth/ diameter/ width of stem/ gives rise to new/ additional xylem and phloem tissues 17. K.C.S.E 2009 PP1 No.29 Explain why the rate of transpiration is reduced when humidity is high  When humidity in high the air around the leaf gets saturated with water vapor hence) less space for water vapor from the leaf to occupy/ low saturation deficit/ low diffusion gradient/ the difference in concentration of water vapor in the atmosphere and in the air spaces is greatly/ highly reduced. 61

18. K.C.S.E 2010 PP2 NO 2 The diagram below shows a transverse section of a plant organ. o a) Name the plant organ from which the section obtained (1 mark)  stem b) (i) Name the class to which the plant organ was obtained. (2 marks)  Monocotyledonae (ii) Give a reason for your answer in (b) (i) above  Vascular bundles are scattered and nor arranged in a ring  Absence of pith/ cambium ( c) Name the part labeled x  Epidermis 19. K.C.S.E 2011 PP1 No.20 The number of stomata on the lower and upper surface of two leaves from plant X and Y were counted under the field of view of a light microscope. The results were as shown in the table below. Leaf Number of stomata Upper surface Lower surface X4 12 Y 20 23 (a)Which of the leaves would be expected to have a lower rate of transpiration? X (b)Given a reason for your answer in (a) above  X has fewer stomata; most stomata in leaf X are concentrated on the lower side 62

20. K.C.S.E 2011 PP2 No.7 (a) Explain how structural features in terrestrial plants affect their rate of transpiration. (13 marks)  Plants in arid/semi arid/desert habitats have leaves covered with thick/waxy cuticles that are waterproof/ impermeable to water allowing for reduced rate of transpiration  Sunken stomata in some desert/semi arid areas plants have water vapour accumulating in the pits, reducing rate of transpiration as moisture in the pits is not carried away by wind.)  Most plants have few or no stomata on the upper surface of the leaf/more stomata on the lower surface of sheltered from direct sunlight, small stomata/small stomata size, thus reducing rate of transpiration.  Plants with small/need like leaves/ spines expose less S/A hence reduced rate of transpiration.  Leaves with shinny surfaces, reflect light resulting in reduced leaf temp, thus reduced rate of transpiration.  Some plants have leaves covered /scales trap a larger of moisture, on the leaf surface reducing transpiration.  Plants growing in wet habitats/mesophylls have thin layer of cuticle, which allow high rate of transpiration, Broad leaves, expose large SA, Many stomata on both surfaces of the leaf , have large stomata aperture 21. K.C.S.E 2012 PP1 No.18 Why are plants able to accumulate most of their waste products for long? (1 mark)  Most of the waste products are harmless;  Waste products are converted into harmless products; 22. K.C.S.E 2012 PP2 No.8 (b) Describe how environmental factors increase the rate of transpiration in terrestrial plants. (10 marks)  In bright light; stomata are fully/wide open; exposing air spaces in the leaf to atmosphere; this intern increase water loss by evaporation through open stomata. High temperatures; increase the rate of evaporation from the leaf surface/ stem; thus more water vapor leading cells due to the increased diffusion gradient; In a windy day; air around the leaf/ stem; increasing diffusion gradient between the leaf air spaces/ stem and the atmosphere; in low humidity/ when the atmosphere is less saturated with water vapor; more water vapor will move from leaf air spaces/ stem due to increase diffusion gradient; low atmospheric pressure; increases diffusion gradient between atmosphere and stem/ leaf increases rate of evaporation; leading to increased rate of transpiration. Availability of water; causes turgidity of guard cells hence stomata open; increasing the rate of transpiration. 63

23. KCSE 2013 PPI NO 7 Explain how the following forces contribute to the movements of water up the xylem (a)Cohesion;  In Cohesion similar molecules mainly water draws attraction this enhance capillarity (b) Adhesion. (2mks)  In adhesion the attraction between water molecules and the wall of the xylem vessel allow upward movement of water. 8.1 24. K.C.S.E 2013 PP1 NO 25 State one adaptation of xylem vessels to their function. (2mks)  Narrow lumen to enhance capillary  Lignified to give mechanical support 25. KCSE 2014 PP1 NO 23 Below is an illustration of a cross section of a plant root showing the transportation of substances in the plant. (a) Name the substances transported along the paths labelled K and L. (2 marks)  K; Photosynthetic products manufactured food  L-Water and mineral salts. (b) Give a reason for your answer in L above. (1 mark)  The substances are moved into the (star shaped ) xylem; 64

5. (b) TRANSPORT IN ANIMALS 1. K.C.S.E 1996 PP1 No.2 State two ways by which acquired Immune deficiency syndrome (A.I.D.S) Virus is transmitted. (2 marks)  Sexual intercourse with an infected person  Blood transfusion from an infected person  Sharing needle/syringes/ razors with an infected person 2. K.C.S.E 1996 PP1 No.14 (a) Describe the path taken by carbon dioxide released from the tissue of an insect to the atmosphere (3 marks)  CO2 diffuses into tracheoles follows the trachea and out through spiracles 3. K.C.S.E 1996 PP1 No.17 (a) How may excessive bleeding results in death? (4 marks)  Anaemia/ low blood volume/ loss of iron/ low red blood cells/ low haemoglobin; leading to low oxygen; loss of nutrients and dehydrations. (b) Name the process by which the human body naturally stops bleeding? (1 mark)  Blood clotting (c) How can low blood volume be brought back to normal(3 marks)  Transfusion; taking fluids) eating iron rich food stuff/ taking iron tablets 4. K.C.S.E 1998 PP1 No.1 Why are people with blood group O universal donors?  Blood has no antigens and does not cause agglutination (with other types) 5. K.C.S.E 2001 PP1 No.3 A person whose blood groups are AB requires a blood transfusion. Name the blood groups of the donors A B  AB O 6. K.C.S.E 2001 PP1 No.8 65 (a) The type of circulatory system found in members of the class insecta is  Open circulatory system

(b) Name the blood vessel that transports blood from: (i) Small intestines to the liver  Hepatic portal vein (ii) Lungs to the heart  Pulmonary vein 7. K.C.S.E 2001 PP1 No.3 In what form is oxygen transported from the lungs to the tissues?  Oxyhaemoglobin 8. K.C.S.E 2004 PP1 No.2 Distinguish between natural and acquired immunity (2marks)  Natural immunity is inherited / transmitted from parent to offspring;  Acquired immunity is developed after suffering from a disease / through vaccination. 9. K.C.S.E 2004 PP1 No.13 The diagram below shows a vertical section through a mammalian heart. a) Name the parts labeled A, B, E and F (4mks)  A - Pulmonary vein  B - Left atrium I auricle  E - Tricuspid valve  F - Pulmonary artery 66

b) Use arrows to show the direction in which blood flows in the heart. (2mks)  c) Give a reason why the wall of chamber C is thicker than chamber D (2 marks)  The left ventricle ‘C’ pumps blood a longer distance to all parts of the body; while the right ventricle ‘D’ pumps blood to a shorter distance/ to the lungs; therefore the left ventricle has thicker walls to generate or exert more pressure. 10. K.C.S.E 2005 PP1 No.9 Why would carboxyhaemoglobin lead to death? (2marks)  It does not easily dissociate and therefore reduces the capacity of hemoglobin to transport oxygen to the tissues leading to suffocation 11. K.C.S.E 2006 PP1 No.7 a) Name one defect of circulatory system in humans. (1mark)  Thrombosis/Varicose veins/Arterion sclerosis/ Antheroma  Antherosclerosis  Accept cerebral vascular thrombosis b) State three functions of blood other than transport. (3 marks)  Regulation of the body temperature  Regulation of pH of fluids  Defense against disease – causing organism/ pathogens/ infection.  Prevent excessive bleeding by enhancing clotting/ prevent excessive loss of blood 12. K.C.S.E 2007 PP1 No.11 (a) What prevents blood in veins from flowing backwards? (1 mark)  Presence of valves 67

(b)State two ways in which the red blood cells are adapted to their function (2 marks)  Have biconcave shape to increase surface area for absorption of gases  Thin capithelium to reduce distance of diffusion of gases  Absence of nucleus and other organelles to increase packaging of hemoglobin  Presence of red pigment hemoglobin that has high affinity for oxygen 13. K.C.S.E 2008 PP1 No.10 a) Name the antigens that determine human blood groups (2 marks)  A and B b) State the adaptation that enables the red blood cells to move in blood capillaries (1 mark)  Ability to change shape 14. K.C.S.E 2008 PP1 No.20 (a) What is a single circulatory system (1 mark)  Blood goes through the heart once in very complete circulation (b)Name an organism which has single circulatory system (1 mark)  Fish (c) Name the opening to the chamber of the heart of an insect (1 mark)  Ostium 15. K.C.S.E 2009 PP1 No.28 (a) State three structural differences between arteries and veins in mammals Arteries Veins - Thick muscular walls - This muscular walls - No valves ( expect at bases - Have valves of pulmonary artery and - Wide lumen aorta) - Narrow lumen (b) Name a disease that causes thickening and hardening of arteries (1mark)  Arteriosclerosis/ rej Atheroma – due to the deposition of cholesterol which makes human narrow 68

16. K.C.S.E 2010 PP1 No.14 Explain why is not advisable to be in a poorly ventilated room with a burning charcoal (3 marks)  Leads to the formation of carbon (II) oxide. This combines with haemoglobin to form carboxyhaemoglobinthat is stable and reduces the oxygen carrying capacity of haemoglobin leading to suffocation 17. K.C.S.E 2010 PP1 No.23 Explain three ways in which red blood cells are adapted to their function. (3 marks)  Absence of nucleus, increase of space for packaging haemoglobin (for carrying oxygen)  Possession of haemoglobin which has high affinity for oxygen  Bi-concave shape creates large surface area for combining with oxygen  Ability to change shape/flexible to enable them pass through capillaries.  Have carbonic anhydrate which increase CO2 transportation  Are numerous/ many to be able to carry max amount of oxygen  Has plasma membrane which allow rapid diffusion of gases 18. K.C.S.E 2010 PP1 No.28 State three structural differences between arteries and veins. (3 marks)  Arteries have thick muscular walls; veins have thin and less muscular walls  Arteries have narrow lumen, veins have wider lumen  Arteries have no valves except at junction with heart; veins have valves at regular intervals 19. K.C.S.E 2010 PP2 No.2 The diagram below shows blood circulation in a mammalian tissue. (a)Name the part labeled P and Q (2 marks)  P – Tissue fluid / intercellular fluid/ space.  Q – Venule. 69

(b)Name the substances that are: (i)Required for respiration that move out of capillaries; (2 marks)  Glucose, oxygen; Rej: formulae (ii)Remove from tissue cells as a result of respiration (2 marks)  Carbon (IV) oxide, water; Rej; carbon dioxide OR Formula (c)Explain how substances move from blood capillaries into the tissue cells. (2marks)  Blood entering the arteriole has a higher pressure; than that leaving the venule, the pressure force water and small solutes (molecules) in blood to go through capillary wall forming tissue fluid; Nutrients / oxygen in tissue fluid move into the tissue cells by diffusion; Acc. Nutrients like glucose/ mineral salts/ vitamins/ fatty acids & glycerol. (d)Name one component of the blood that is not found in the part labeled P (1 mark)  Red blood cells/ proteins/platelets; Acc one example of protein e.g. globulin. 20. K.C.S.E 2011 PP1 No.16 (a) Describe the condition known as vericose veins.  Weakened/ defective valves in veins; causing blood/ body fluid/ tissues fluid to accumulate; (leading to swelling) (b) What is the role of blood platelets in the clotting process?  When exposed to air) they disintegrate/ burst; releasing thromboplastin/ thromborinase. 21. K.C.S.E 2011 PP1 No.11 (a)State two ways in which heart muscles are special. (2 marks)  They contract and relax without fatigue  They are myogenic (b) Name the muscles found in the following organs; (2 marks) Stomach  Smooth muscles Bone  Skeletal muscles 22. K.C.S.E 2011 PP1 No.27 What is the function of contractile vacuoles in amoeba? (1mark)  Accumulate and excrete excess water 70

23. K.C.S.E 2011 PP1 No.28 State two differences between open and closed circulatory systems (2 marks) Open Closed - Transport fluid under low - Transport fluid under high pressure pressure - Materials transported slowly - Materials transported faster - Organisms less active - Organisms more active - Fluid is general body cavity - Fluid is in special vessels 24. K.C.S.E 2012 PP2 NO (8a) Using a relevant example, describe how an allergic reaction occurs in a human being. (10 marks)  An allergic rxn of a hypersensitive response; eg asthma/hay fever/ any other Rxn to aspecified allergy; Allergic people are hypersensitive to materials like dust/ pollen grains/ some foods/ some drugs/ some pollutants/ (fungal spores/ feathers/ fur/ strong perfumes/ smoke; to an antigen by the body immune system; the body immune system responds by over producing antibodies; against harmless antigens; the antigen - antibody rxn occurs on the surface of the body cells; which burst/ open; and release histamine; cause inflamation,' itching/ swelling/ pain/ breathing difficulties/ constriction of bronchi/ dilation of capillaries/ excessive secretion of mucus/ anaphylaxis/ diarrhea vomiting/ sneezing./coughing; which damage the body. 25. K.C.S.E 2013 PP1 NO 11 1mk) State the advantage of possessing blood group AB.  Can receive blood from all blood groups 26. K.C.S.E 2013 PP1 NO 24 Explain three protective functions of mammalian blood. (3mks)  Phagocyte engulf pathogens  Lysosome release lytic enzymes to destroy the pathogen  Some clump the pathogens preventing spread of disease  Some bind to the membrane reducing multiplication. 27. K.C.S.E 2013 PP2 NO 7 (a) Describe the process of blood clotting in human beings. (10mks)  When vessel in the skin breaks, blood oozes out; platelets releases thrombokinase which neutralizes effect of neparln and also activates conversion of prothrombin to thrombin in the presence of calcium ions. Thrombin activates conversion of soluble fibrinogen to in soluble fibrin which forms a meshwork pattern of fibrins caclot around the damaged vessel preventing further loss of Red blood cells 71

28. K.C.S.E 2014 PP1 NO 19 Why is a burning charcoal stove in a poorly ventilated room likely to cause death of the inhabitants? (3 marks)  Due to limited oxygen, haemoglobin combines with carbon oxide to form carboxyhaemoglobin;  Carboxyhaemoglobin does not readily dissociate hence reduces the capacity of haemoglobin to transport oxygen;  Carbon oxide is therefore a respiratory poison if breathed in for a long time; 29. K.C.S.E 2014 PP1 NO 24 The table provided shows the transportation of substances in the human body. substance Transported by blood From To Oxygen M Whole body N Liver Kidneys P Intestine Whole body Name the substances represented by M -Lungs  N -Urea /ammonia; rej. Nitrogenous wastes P -Digested food / water mineral salts / vitamins 30. K.C.S.E 2014 PP2 NO 2 The diagram below illustrates the role played by red blood cells in the transportation of carbon (IV) oxide o (a)Other than carbon (IV) oxide transportation in the red blood cells, name the other form of carbon (IV) oxide transportation in humans.(1 mark) o Carbonic acid/carbaminohaemoglobin/hydrogen carbonate; 72

(b)(i) Name substance F (1 mark)  Water; (ii) Name the enzyme marked G and state its role in the reaction. (2 marks)  Enzyme: Carbonic acid;  Role: catalyses reaction between carbon iV oxide and water to form (weak) carbonic acid; (c) Explain why transportation of carbon (IV) oxide in red blood cells is advantageous.(2 marks)  Prevents accumulation of acidity/maintain pH of blood; since hydrogen ions combine with haemoglobin;(to form haemoglobin acid) /it is faster due to the catalytic effect of carbonic anhydrase (d) Explain the role of calcium in blood clotting. (2 marks)  Activates thromboplastiri/thrombokinase to neutralize heparin/convert prothrombin to thrombin (student must mention the enzyme to earn second mark) 31. K.C.S.E 2015 PP1. NO.3 (2 marks) An individual is of blood group B positive. (a) Name the antigens in the individual's blood. (b) Give the reason why the individual cannot receive blood from a blood group A donor.(2 marks) 32. K.C.S.E 2015 PP2. NO.8 How is a mammalian heart structurally adapted to its function? (20 marks) 73

6. GASEOUS EXCHANGE Specific Objectives - Gaseous exchange in living organisms (necessity) - Gaseous Exchange in Plants - Mechanisms of opening and closing of stomata - The process of gaseous exchange in root, stem and leaves of both aquatic (floating) and terrestrial plants - Gaseous Exchange in Animals - Types and Characteristics of Respiratory Surfaces - cell membrane, gills, buccal cavity, skin and lungs - Mechanism of gaseous exchange in - Protozoa - amoeba - Insect – grasshopper - Fish – bonyfish - Amphibia – frog - Mammal - human - Factors affecting rate of breathing in humans - Respiratory diseases: Asthma, Bronchitis, Pulmonary tuberculosis, Pneumonia and whooping cough - Practical Activities - Observe permanent slides of cross- sections of aerial and aquatic leaves and stems - Examine the distribution of spiracles on grasshopper or locust - Examine the gills of a bony fish - Dissect a small mammal and identify the structures of the respiratory system (demonstration) Construct and use models to demonstrate breathing mechanisms in a mammal (human) Demonstrate the effect of exercise on the rate of breathing By the end of the topic, the learner should be able to: a) explain the need for gaseous exchange in living organisms b) explain the mechanism of gaseous exchange in plants c) compare the internal structures of aquatic and terrestrial roots, stems and leaves d) examine various types of respiratory structures in animals and relate them to their functions e) state the characteristics of respiratory surfaces f) describe the mechanisms of gaseous exchange in protozoa, insects, fish, frog and mammal g) describe the factors which control the rate of breathing in humans h) state the causes, symptoms and prevention of respiratory diseases. 74

1. K.C.S.E 1998 PP1 No.4 Why are gills in fish highly vascularized? To facilitate transportation of gases/ Exchange of gases; if gases are  mentioned (both must be O2 and CO2 / to create a steep concentration gradient 2. K.C.S.E 2000 PP1 No.11 The diagram below represents a section of a leaf. (a) Name the parts labeled X, and Y  Y – Cuticle  X– Spongy mesopyll (cell) layer (b)Using arrows indicate on the diagram the direction of flow of water during the transpiration stream c).Describe the adaptations of a leaf to gaseous exchange  Broad/ flat leaf (lamina) to provide large surface area or absorption of gases  Thickness: allow gases to pass though fast  Presence of stomata for efficient diffusion of gases  Presence of air spaces for easy diffusion 3. K.C.S.E 2001 PP1 No.10 Name three sites where gaseous exchange takes place in terrestrial plants.  Mesophyll cells  Spongy mesophyll  Palisade mesophyll  Stomata  Substomatal chambers; lenticels  Cuticles. 4. K.C.S.E 2002 PP1 No.9 75 Name two gaseous exchange structures in higher plants  Stomata  Lenticels: (reject cuticle)

5. K.C.S.E 2003 PP1 No.13 The diagram below shows gaseous exchange in tissues. a) Name the gas that diffuses: (i)To the body cells  Oxygen (ii)From the body cells  Carbon (IV) oxide b) Which compound dissociates to release the gas named in (a) (i) above?  Oxyhaemoglobin c)i) what is tissue fluid?  The blood plasma except blood cells and proteins; that has filtered out of the capillaries. ii) What is the importance of tissue fluid?  It is a medium of exchange of substances/ materials between capillaries and body cells; supply nutrients to cells / supply oxygen to cells / remove waste products from cells. d) Name the blood vessel with the highest concentration of: i)Glucose  Hepatic portal vein ii) Carbon (IV) oxide  Pulmonary artery 76

6. K.C.S.E 2005 PP1 No.11 The diagram below represents a part of the rib cage. a) Name the parts labeled W, Y and Z. (3mks)  W – Vertebral column  Y – Sternum  Z – Intercostal muscles b) How does the part labeled Z facilitates breathing in?(3mks)  Contracts and relaxes to help change the volume and pressure of the ribcage leading to exhalation or inhalation 7. K.C.S.E 2005 PP1 No.18 Describe how gaseous exchange takes place in terrestrial Plants. (20mks)  Gaseous exchange in plants involves two main respiratory gases: carbon IV oxide and oxygen.  During daytime green plants take in carbon IV oxide for photosynthesis and oxygen for respiration. During photosynthesis oxygen is given out as a by product and released to the atmosphere.  In plants such as the flowering plants stomata in the leaves and lenticels in the woody stems and pneumatophores/breathing roots in aquatic woody plants provide the surface for gaseous exchange. Gaseous exchange taken place by diffusion across the respiratory surface.  Stomata.These are located mainly in the leaves and in younger parts of the stem. The opening and closing of stomata is controlled mainly by the intensity of light. They are normally open during the day and closed during the night. Several theories explaining the mechanism of stomata opening and closing have been put forward. 77

8. K.C.S.E 2006 PP1 No.5 State two ways in which floating leaves of aquatic plants are adapted to gaseous exchange. (2 marks)  Stomata found on upper epidermis to allow efficient gaseous exchange  Presence of large air spaces/Aerenchyma tissues to enable it float/Bouyant/  Storage of air  Absence of cuticle to enhance gaseous exchange. 9. K.C.S.E 2006 PP1 No.24 State four ways in which respiratory surfaces are suited to their function. (4mks)  Thin walls/ thin epithelium for faster diffusion of gases/ to reduce distance for faster diffusion.  Moist for dissolving gasses  Large surface area for maximum diffusion/ gaseous exchange  Highly vascularized to facilitate diffusion/ to enhance gradient. 10. K.C.S.E 2007 PP1 No.12 (a) Name two structures for gaseous exchange in aquatic plants (2 marks)  Pneumatophores  Aerenchyma tissues  Cuticle (b)What is the effect of contraction of the diaphragm muscles during breathing in mammals? (3 marks)  Leads to the flattening of the diaphragm. This increases the volume of the ribcage and lowers pressure inside compared to atmospheric pressure leading to inspiration 78

11. K.C.S.E 2007 PP2 No.1 The diagram below represents some gaseous exchange structures in humans (a) Name the structures labeled K, L, and M (3 marks)  K- Pleural membranes  L- Alveolus  M- Intercostal muscles (b) How is the structure labeled J suited to its function? (3 marks)  Has c- shaped cartilage rings that support it preventing it from collapsing and allow free flow of air  Inner lining has mucus secreting cells that trap fine dust particles and micro- organisms  Inner lining has hair like structures called cilia that enhance upward movement of the mucus to the larynx (c)Name the process by which inhaled air moves from the structure labeled L into blood capillaries (1mk)  Diffusion (d ) Give the scientific name of the organism that causes tuberculosis in humans ( 1 mark)  Mycobacterium tuberculosis (underline separately). Reject if not done so. 12. K.C.S.E 2008 PP2 No.8 (a)State four characteristics of gaseous exchange surfaces (4 marks)  Highly vascularized/ network of blood capillaries  Large surface area for gaseous exchange  Thin membrane/ epithelium/ one cell thick wall/ thin lining; rej thin walls moist lining 79

(b)Describe the mechanism of gaseous exchange in a mammal (16 marks) Breathing in  External intercostals muscles contract; internal, intercostals muscles relax lifting/ raising the ribcage upwards and outwards; muscles of diaphragm contract. It flattens the volume of the thoracic cavity increases; pressure decrease; higher air pressure in the atmosphere forces air into the lungs Breathing out  External intercostals/ muscles relax; internal intercostals muscles contract moving the ribcage downwards and inwards; the muscles of diaphragm relax, the diaphragm assumes dome shape; volume of thoracic cavity decreases; while pressure increases; higher pressure forces air out of the lungs. 13. K.C.S.E 2009 PP1 No.16 (a) Name the gaseous exchange surface in insects ( 1 mark)  Tracheole Rej: Trachea/ Tracheole system b). How is the surface named in (a) above suited to its function (2 marks)  Moist for gases to dissolve (in solution) Branched/ ramified with numerous tubes to increase surface area (for gaseous exchange) 14. K.C.S.E 2010 PP1 No.5 State three ways in which a respiratory surface is adapted to its function. (3 marks)  A large surface area for efficient diffusion of gases  Moist for gases to diffuse in solution form/to dissolve gases  Thin for efficient/diffusion of gases (across a short distance)  Most be close to body cells/well supplied with blood vessel to active cells  Ventilation mechanism for bringing in air rich in O2 and expelling air rich in carbon(iv) oxide 15. K.C.S.E 2011 PP1 NO 19 (a) Apart from the lungs, name two gaseous exchange surfaces in a frog.  Skin  Buccal cavity/ mouth cavity; rej mouth 80

16. K.C.S.E 2011 PP1 No.22 State the difference in content of oxygen and carbon (IV) oxide in the air that enters and leaves the human ling.  Air that enter the lungs has high content of oxygen than air that leaves  Air that enter lungs has lower content of CO2 than air that leaves Acc; air that enter lungs has 20% – 21% Oxygen, air that leaves has  15% - 17% Oxygen air that enter lungs has 0.03 – 0.04% CO2, air that leaves has 4.0% CO2 17. K.C.S.E 2011 PP2 No.3 (a) Name the causative agent for the following respiratory diseases. (2marks) (i)Whooping cough.  Bordetella pertussis (underline separately) (ii)Pneumonia  Streptococcus pneumonia/Acc para influenza virus/ influenza virus young chrolo mycoplasma pnu (b)Describe how oxygen in the alveolus reaches the red blood cells. (4marks)  Inhaled O2 dissolves in moisture in the alveclus; since the O2 concentration in blood is lower than a alveolus; O2 diffuse; thro epithelium the capillary wall into the plasma/blood/blood cells and finally into the red blood cell (c) How are the pnematophores adapted to their function? (2marks)  Grow into the air above mud/water  Have lenticels is for gaseous exchange 18. K.C.S.E 2012 PP1 No.6 The diagram below represents part of the gaseous exchange system in human. (a) Name the parts labeled F and G.  F- Bronchus; Reject bronchioles;  G - Intercostal muscles/ external intercostal muscles; Reject internal intercostal muscles. 81

(b) State one function of each of the parts labeled H and J.  H- (Pleural membranes) secrete/ enclose pleural fluid (to lubricate lungs); protect the lungs;  J - (Diaphragm/ diaphragm muscles) separates chest/ thoracic cavity;  Accept it works to effect volume; / pressure changes in chest cavity necessary for inhalation and exhalation/ ventilation. Accept relevant explanation for the working except that both inhalation and exhalation must be brought out clearly to score; 19. K.C.S.E 2012 PP2 No.5 (a) Describe the process of inhalation. (4marks)  The external intercostal muscles contract while internal intercostal muscles relax; ribcage is pulled upwards and outwards; the diaphragm flattens; the volume of the thoracic cavity/ lungs increases/ the pressure in the thoracic cavity decreases; air rushed into the lungs; from the atmosphere through the nose. b) Explain the mechanism of stomatal opening. (4marks)  Osmotic pressure of guard cells increases when sugar glucose is manufactured during photosynthesis/ starch converted to sugar in low acidity/ potassium ions moves into guard cells during the day; water enters guard cells from the surrounding cells by osmosis; because the guard cells have thin outer walls and thick inner walls the thin outer walls stetch/ expand more as the cell become turgid; thus the thick inner wall curves; causing the stomatal aperture to open. 20. K.C.S.E 2013 PP1 NO 10. How are lenticels adapted for gaseous exchange? (2mks)  Lenticels has raised pits to enhance gaseous exchange. Can receive blood from all blood groups. 21. K.C.S.E 2013 PP2 NO 7(b) How are respiratory surfaces in mammals adapted to their functions? (10mks)  Moist to dissolve respiratory gases.  Highly vascularised for rapid uptake of respiratory gases.  Thin epithelial lining to reduce distance for diffusion of respiratory gases.  Numerous to increase surface area for diffusion of respiratory surfaces  A good ventilation system to enhance entry and exit of respiratory gases. 82

22. K.C.S.E 2014 PP1 NO 12 The diagram below represents a model used to demonstrate breathing in mammals. a)Name the mammalian structure represented by the parts labelled D and E (1mk)  D Rib-cage  E Diaphragm (b)State the observation made when the string is pulled downwards. (1 mark)  The balloons are inflated (c. Explain the observation in (b) above. (2 mark)  Pulling down the string increases the volume of D hence decreasing the pressure inside;  The low pressure causes external atmospheric air to rush in and inflate the balloon. 23. K.C.S.E 2014 PP1 NO 27 The diagram below shows the gaseous exchange system of a locust. (a) Name the structure labelled Q. (1 mark)  Spiracle (b) State the function of the part labelled R. (1 mark)  Keep the trachea open for air passage; 83

(c) How is the part labelled S structurally adapted to its function? (1 mark)  Lacks spiral bands of chitin / to make it thin; for diffusion of gases;  Moist; to dissolve respiratory gases; 24. K.C.S.E 2014 PP2 NO 3 (a) Describe the mechanism of gaseous exchange in plants through the lenticels. (3 marks)  Oxygen concentration is higher outside than inside the lenticeis; 02 diffuses into lenticels then into the cells; C02 concentration is higher inside the lenticels than on the outside: C02 diffuses out of the lenticels (into the atmosphere) (b) Explain each of the following: (i) The tracheoles lack spiral bands of chitin; (3 marks)  To provide a large surface area; make them thin; rej thin membrane for gaseous exchange/to reduce diffusion distance for respiratory gases (ii) The floor of the mouth is lowered during inhalation in a bony fish.(2 marks)  This increases the volume of the buccal cavity while decreasing the pressure; which forces water to rush into the mouth. 25. K.C.S.E 2014 PP1 NO.7 How is a guard cell structurally adapted for gaseous exchange? (4 marks) 26. K.C.S.E 2015 PP1 NO.11 Name two structures used for gaseous exchange in plants.(2 marks) 84

27. K.C.S.E 2015 PP2 NO.1 The diagram below illustrates a blood capillary surrounding a structure for gaseous exchange in human beings.  (a)Name the gaseous exchange structure.(1 mark) (b)Identify the gases labelled Y and Z. Y......................................................(1 mark) Z ......................................................................(1 mark) (c)How does the gas labelled Y reach the inside of the blood capillary? (3 marks) (d) How does cigarette smoking lead to lung cancer? (2 marks) 85

7. RESPIRATION Specific Objectives Meaning and significance of respiration Tissue respiration  Mitochondrion - structure and function  Aerobic respiration (Details of kreb’s cycle not required)  Anaerobic respiration in plants and animals, the products and by- products  Application of anaerobic respiration in industry and at home  Compare the energy output of aerobic and anaerobic respiration Practical Activities Carry out experiments to Investigate  The gas produced when food is burnt  The gas produced during fermentation  Heat production by germinating seeds By the end of the topic, the learner should be able to: a) explain the significance of respiration in living organisms b) distinguish between aerobic and anaerobic respiration c) describe the economic importance of anaerobic respiration in industry and at home d) describe experiments to show that respiration takes place in plants and animals. 86

1. K.C.S.E 1996 PP1 No.13 The diagram below shows a set – up that was used to demonstrate fermentation. Glucose solution was boiled and oil added on top of it. The glucose solution was then allowed to cool before suspension was added. (a)Why was the glucose solution boiled before adding the yeast suspension? (1 mark)  To expel oxygen (b)What was the importance of cooling the glucose solution before adding the yeast suspension? (1 mark)  To avoid denaturing yeast enzymes (c)What was the use of oil in the experiment? (1 mark)  To prevent entry of oxygen (d)What observation would be made in test tube B at the end of the experiment? (1 mark)  Formation of white precipitate (e)Suggest a control for this experiment (1mark)  Use of boiled yeast cells/ use of water instead of glucose solution 2. K.C.S.E 1997 PP1 No.3 What are the three end products of anaerobic respiration in plants  Alcohol, carbon dioxide and energy; accept Ethanol, C2H5OH/CH3H2OH. 87

3. K.C.S.E 1999 PP1 No.2 Give two reasons why accumulation of lactic acid during vigorous exercise leads to an increase in heartbeat.  Lactic acid is poisonous to tissue and must be removed.  To increase supply of oxygen to tissues. 4. K.C.S.E 1999 PP1 No.16 Describe the: o Process of inhalation in mammals.  Muscles of diaphragm contract; causing the diaphragm to flatten (from dome position. The external intercostals muscles contract internal intercostals muscles relax pulling the ribcage upward/forward and outward in man. This movement increases the volume of the thoracic cavity; reducing the pressure; of the thoracic cavity; compared to atmospheric pressure; this causes the atmospheric air to rush into the lungs. (Through the nostrils, trachea bronchioles and alveoli). b) Mechanisms of opening and closing of stomata in plants Theory- photosynthesis  Guard cells have chloroplasts; in the presence of light; photosynthesis occurs in guard cells, producing sugar in guard cells; osmotic pressure increases/osmotic potential lowers; water from neighboring /adjacent cells enter into guard cells; causing turgidity of guard cells; causing turgidity of guard cells. Theory 1.  Guard cells have chloplasts; in the presence of light photosynthesis occur in the guard cells of stomata; producing in the guard cells; osmotic pressure increases/lowers osmotic potential water from the neighboring /adjacent cells, enter into guard cells; causing turgidity of guard cells . The inner walls of the guard cells are thicker than outer walls; so during turgidity the inner walls stretch more; causing the guard cells to bulge outward; stomata opens Theory 2.  Guard cells have chloroplasts (Day) in light; photosynthesis occurs in the leaf/guard cells lowering the CO2 concentrations; this increases PH/alkalinity which triggers of enzymatic conversion of starch to sugar (glucose); leading to low osmotic potential/ increased osmotic pressure in guard cells; guard cells absorb water from epidermal cells; thus becoming turgid; the inner walls are thicker than the outer walls; outer walls stench more than inner walls; causing guard cells to bulge outwards, stomata opens; In the absence of light (night); no photosynthesis; CO2 concentration increases due to respiration; PH lowered/ acidity increases; sugar converted to starch; osmotic pressure lowered/ osmotic potential increases; guard cells lose water to adjacent epidermal cell becoming flaccid; stomata close. 88

 Day low H+ high PH opens stomata.  Starch glucose.  Theory 3  Guard cells have chloroplasts; in light AT produced; the energy drives K+ irons from adjacent epidermal cells into guard cells; accumulation of K+ raises osmotic pressure (lower osmotic potential) of guard cells; guard cells absorbs water from adjacent epidermal cells; becoming turgid; the inner walls are thicker than the outer walls so outer walls stretch more than inner walls causing guard cells to bulge outward. Stomata opens. In the absence of light (night ) ATP rapidly decreases; no energy of potassium +ions pump ion; migrate by diffusion from guard cells to adjacent epidermal cells; become flaccid; the thinner outer walls of guard cells shrink (OWWTE; thicker inner walls reduces their curvature/OWTTE; thus closing the stomata. 5. K.C.S.E 2000 PP1 No.14 The concentration of the lactic acid in blood during and after an exercise was determined. The results are shown in the graph below (a)(i) By how much did the lactic acid increase at the end of 13 89 minutes?  78/78 mg/ 100cm3 (ii) After how many minutes was the lactic acid concentration 71mg/100cm3?  8.5th and 29.5th / 8min 30 sec and 29 min 30 sec

(iii) What would be the concentration of lactic acid at the 60th minute?  47 mg/100cc; Acc. 47 (b)Give a reason for the high rate of production of lactic acid during the Exercise  The demand for oxygen is more than the supply leading to anaerobic respiration. Acc. Lactic acid converted to glucose/Glycogen (c) Give a reason for the decrease in the concentration of lactic acid after the exercise  Lactic acid is oxidized (to form CO2 and H2O). Acc. Lactic acid is converted to glucose/ glycogen 6. K.C.S.E 2003 PP1 No.1 A process that occurs in plants is represented by the equation below. C6H12O6 → 2C2H5OH + 2CO2 + Energy (Glucose) (Ethanol) (Carbon (IV) oxide) (a)Name the process.  Anaerobic respiration / fermentation; Acc. Alcohol production / drawing dough. b) State the economic importance of the process named in (a) above  Brewing/ Baking.  Production of milk products e.g. yoghurt 7. K.C.S.E 2004 PP1 No.4 Other than carbon dioxide, name other products of anaerobic respiration (2mks)  Ethanol / Alcohol  Energy / ATP/ 210kj / heat; Rej. atp, formula of alcohol. 8. K.C.S.E 2005 PP1 No.6 Name the substance which accumulates in muscles when respiration occurs with insufficient oxygen.  Lactic acid 9. K.C.S.E 2006 PP1 No.13 (1mk) a)In what form is energy stored in muscles  A.T.P/ adenosine triphosphate rej A.T.P 90

(b)State the economic important of anaerobic respiration in plants. (2mks)  Brewing of alcohol accept examples;  Baking of bread.  Biogas production  Compost manure formation  Silage formation  Commercial production of citric acid  Sewage treatment. 10. K.C.S.E 2006 PP1 No.25 a) A dog weighing 15.2kg requires 216kj while a mouse weighing 50g requires 2736kj per day. Explain. (2mks)  A rat has a large surface area to volume ratio thus loses energy faster than a dog therefore need for more energy to replace that lost (b) What is the end-product of respiration in animals when there is insufficient oxygen?  Lactic acid , energy 11. K.C.S.E 2007 PP1 No.13 (a)Name the products of anaerobic respiration in (i) Plants (1 mark)  Ethanol, CO2 and energy (ii) Animals (1 mark)  Lactic acid  Energy (b) What is oxygen debt? (1 mark)  The amount of oxygen required to eliminate lactic and that accumulates in muscles when the oxygen demand is more than supply 12. K.C.S.E 2008 PP1 No.9 Give three factors that determine the amount of energy a human being requires in a day (3 marks)  Body size  sex  age 13. K.C.S.E 2008 PP1 No.15 Explain what happens when there is oxygen debt in human muscles (2 marks)  Muscles respire anaerobically; resulting in accumulation of lactic acid in the tissue; causing fatigue/ muscle crumps. 91

14. K.C.S.E 2008 PP1 No.27 Explain how anaerobic respiration is applied in sewage treatments. (1 mark)  (Anaerobes) micro organism/ bacteria breakdown harmful substances in sewage 15. K.C.S.E 2009 PP1 No.26 How are the mitochondria adapted to their functions? (2 marks)  Inner membrane is highly folded/ have cristae to provide a large surface area/ for attachment of respiratory enzyme. 16. K.C.S.E 2009 PP1 No.27 State two ways in which anaerobic respiration is applied in industries  Baking/ brewing - Rej: Formation of butter, cream, glucose.  Formation of dairy products- cheese, yoghourt, sour milk.  Formation of organic acids- oxalic acid, vinegar (Ethamic acid, citric acid, butyric acid) 17. K.C.S.E 2010 PP1 No.1 In an experiment, disinfection soaked bean seeds were put in a vacuum flask which was then fitted with a thermometer as shown in the diagram below. The temperature readings were taken every morning for three consecutive days. (a)Which process was being investigated? (1 mark)  Respiration (Rej: external respiration/ anaerobic respiration). Acc: aerobic respiration. (b i) What were the expected results? (1 mark)  Rise/ increase in thermometer / temperature reading. ii) Account for the answer in (b) (i) above? (2 marks)  Stored starch/ glucose/ carbohydrates in germination seeds are broken down/ oxidized to get energy. Some of the energy is released to get energy; some of the energy is released as heat. 92

(c)Why were the seeds disinfected? (2 marks)  To kill bacteria/ fungi/ micro-organisms; that would cause decay/ decomposition / respire. (of the bean). (d)Why was a vacuum flask used in the set-up? (1 mark)  To conserve heat/prevent heat loss to surrounding (e)How would a control for this experiment be set ( 1mark)  Use similar set up with dead disinfected seed.  Use dead disinfected bean seed/ use of dry bean seeds; acc formaldehyde / formalin for disinfection sodium hypochlorite. 18. K.C.S.E 2011 PP1 No.10 (a) Give two differences in the products of anaerobic respiration between plants and animals.  Lactic acid in animals while plants is ethanol / alcohol  No CO2 produced in anaerobic respiration in animals while anaerobic respiration in plants produces CO2 (b) Name the site of anaerobic respiration in a cell.  Cytoplasm 19. K.C.S.E 2011 PP1 No. 19(b) Write an equation that summarizes the process of aerobic respiration.  Glucose + Oxygen → Carbon (IV) oxide + water + energy OR C6H12O6 + 6O2 6CO2 + 6H2O + ATP/ energy 20. K.C.S.E 2012 PP1 No.14 (1 mark) (a)Name the type of respiration that is most efficient.  Aerobic respiration; ( b) Give a reason for your answer in (a) above (1mark)  It releases more energy (per unit mass). Reject alot of energy alone/ comparison aspect must come cut. If units given, they must be correct/ 2880kj/g. 21. K.C.S.E 2012 PP1 No.7 The diagram below represents a set-up that students used in an investigation. o 93

(a) Name-the physiological process that was being investigated. (1 mark)  Respiration/Aerobic respiration (b) State the role of potassium hydroxide in flask K. (1 mark)  (Potassium hydroxide, removes/ absorbs/ takes away carbon (IV) oxide from the atmospheric air); Accept Co2/ Reject carbon dioxide; Reject if the carbon (IV) oxide is without IV bracketed. (c)Account for the observation in boiling tube L and flask N. (2 marks)  L - Lime water remains clear because carbon (IV) oxide has been removed; Must explain why carbon (IV) oxide is absent/ missing;  N - Lime water forms a white precipitate because the respiring cockroaches produce carbon (IV) oxide; Idea of respiration must come out; Reject milky; 22. KCSE 2013 PP1 NO 14 Name three end products of anaerobic respiration in plants. (3mks)  Carbon (iv) oxide  Ethanol  Energy as A.T. P 23. KCSE 2013 PP1 NO 15 State two reasons why accumulation of lactic acid leads to increase in heart beat. (2mks)  Increase blood rich in oxygen to supplied to respiring tissue  Accelerate breakdown of toxic lactic acid to carbon (IV) oxide and water. 24. KCSE 2015 PP1 NO.9 The diagram below shows an experimental set up to investigate a certain physiological processing plants.  (a)State the aim of the experiment.(1 mark) (b)State the role of the following in the experiment: 94

(i) potassium hydroxide;(1 mark) 95

(ii) aluminium foil.(1 mark) (c)Account for the expected colour change in tube F. (2 marks) 96

8. EXCRETION AND HOMEOSTATIS Specific Objectives Excretion in Plants - Methods of excretion in plants - Useful and harmful excretory products of plants and their economic importance e.g. caffeine in tea and coffee, quinine, tannins, colchicines, cocaine, rubber, gum, papain (from pawpaw) and products of cannabis sativa (bhang) and khat (miraa) Excretion and homeostasis in Animals - Distinction between excretion, homeostasis and egestion - Excretion in a named uni-cellular organism (protozoa) - Structure and functions of skin and kidney - Neuro-endocrine system and homeostasis - Water balance (blood osmotic pressure) - Blood sugar level (control) - Temperature regulation (mention the role of hypothalamus) - Common kidney diseases, their symptoms and possible methods of prevention and control - The role of the skin in thermoregulation, salt and water balance. - Major functions of the liver and their contributions to homeostasis - Common diseases of the liver, their symptoms and possible methods of prevention/control Practical Activities - Examine and draw the mammalian kidney - Make vertical sections of the kidney to identify cortex and medulla - Observe permanent slides of mammalian skin - Investigate effect of catalase enzyme on hydrogen peroxide By the end of the topic, the learner should be able to: 97 a) distinguish between excretion and egestion b) explain the necessity for excretion in plants and animals c) state the uses of excretory products of plants d) describe the methods of excretion in a named unicellular organism e) relate the structures of the human skin, lungs, liver and kidney to their functions name common kidney diseases g) explain the concept of internal environment and homeostasis h) compare responses to changes in temperature by behavioural and physiological methods in animals i) relate heat loss to body size in j) describe methods by which mammals gain and lose heat k) explain how the functions of the following relate to homeostasis - skin, hypothalamus, liver and kidney I) discuss the role of antidiuretic hormone, insulin and glucagons m) describe simple symptoms of Diabetes mellitus and Diabetes

insipidus. Practical Activities Examine and draw the mammalian kidney Make vertical sections of the kidney to identify cortex and medulla Observe permanent slides of mammalian skin Investigate effect of catalase enzyme on hydrogen peroxide 98

1. K.C.S.E 1995 PP1 No.17 Describe how excretion takes place in (i) Mammalian Kidneys  Blood reaches the kidney from the renal/ renal artery enters the kidney; then branches into capillaries/ glomeruli/ in the Bowmna’s capsule, blood vessels leaving the capsule/ efferent are those entering it/ afferent causing high pressure to develop in the glomeruli. This forces the plasma/ causes ultra filtration into the capsule. The filtrate contains waste products (acc. One example) The filtrate moves into the proximal/ first convolulated tubule; where selective reabsorption of glucose amino acids, some water and vitamins take through the loop of henle; excretory products/ urea, excess water and salts acc, one example) pass into the distal tubule, where the remaining useful substance (acc. One example e.g salts and water) are reabsorbed; The filtrate passes into the collecting tubule; where more reabsorption of water takes place: Excess water, urea and salts ( all three must appear)/Urine are removed through the ureter. (ii) Green plants (5 marks)  CO2 / O2 /H2O diffuse through the stomata lentils/ hydrathods some toxic wastes are converted into non – toxic substances; these are deposited in certain tissues of the plant/ stored in ageing structures. Resins/ tannins – are exuded though the bark of the stem; or lost during leaf fall. 2. K.C.S.E 1996 PP1 No.21 Explain how the mammalian skin is adapted to perform its functions (20 marks)  The cornified layer is made up of dead cells, that prevent entry of bacteria and prevent physical damage; melanin protects the body against U-V variation; sebaceous glands produce a chemical/ ring substance which is of blood vessel; which when the body temperature is high dilate and heat is lost or when body temp is low blood vessels constrict and heat is retained. Hair when it is called, stands and traps air between themselves; to retain heat/ stop heat loss or when it is hot hair lies flat close on the skin; so does not trap air, and therefore heat is retained and sweat is lost; the skin has sweat glands which produces sweat; sweat evaporates thus cooling the body. 3. K.C.S.E 1997 PP1 No.8 A person was found to pass out large volumes of dilute urine frequently. (2 marks) Name the (a) Disease the person was suffering from  Diabetes inspidus ref. Diuresis/ water diabetes 99

(b)Hormone that was deficient  Antidiuretic hormone/ ADH/Vasopressin 4. K.C.S.E 1997 PP1 No.15 The equation below represents a metabolic that occurs in the mammalian liver Amino acids →Organic compounds + urea (a)Name the process.  Deamination (b)What is the importance of the process to the mammal?  Breaks down amino acids (c)What is the source of amino acids in this process  Digested proteins (d)What is the difference between essential and nonessential amino acids?  Essential amino acids must be obtained from the diet while non essential amino acids can be synthesized by the body 5. K.C.S.E 1999 PP1 No.11 Give reasons for each of the following: a) Constant body temperature is maintained in mammals.  Constant body temperature is maintained in mammals  Most enzymes in the body function within a narrow range of temperature;  High temperature above optimum denature enzymes  Low temperature inactive /inhabit enzymes b) Low blood sugar level is harmful to the body.  Sugar in a raw material for respiration, hence less energy, available to body/low/rate of metabolism. 6. K.C.S.E 2000 PP1 No.4 State the importance of osmo-regulation in organisms  Maintenance of constant levels of water/ salt/ ions/ osmotic pressure/ for optimum conditions of metabolism/ cellular functions 100