NAME........................................................................................CLASS...............ADM…………. DATE……………………….SIGN………………………………SCHOOL…………………… 231/1 BIOLOGY PAPER 1 JULY 2024 TIME: 2 HOURS MOKASA 2 EXAMINATIONS (Kenya Certificate of Secondary Education) BIOLOGY THEORY Instructions Write your name, class and admission number in the space provided above. Write the date of the examination and sign in the space provided above. Answer all the questions in the spaces provided. You may be penalized for wrong spelling especially technical terms. For Examiner’s Use Only QUESTION MAXIMUM SCORE CANDIDATES SCORE 1-32 80 This paper consists of 12 printed pages. Candidates should check the question paper to ascertain that all the pages are printed as indicated and no questions are missing. C:\Users\THIS PC\AppData\Local\Microsoft\Windows\INetCache\Content.Word\Screenshot_2024-07-04-10-50-14-28_40deb401b9ffe8e1df2f1cc5ba480b12.jpg 1. Name the cell organelles that carryout the following functions. (3mks) (i) Destroy old and worn-out organelles ……………………………………………………………………………………… (ii) Formation of spindle fibres ……………………………………………………………………………………… (iii) Osmoregulation ……………………………………………………………………………………… 2. i) State the importance of rings of chitin in the tracheal system of insects. (lmk) ............................................................................................................................................................ .......................................................................................................................................................... ii) Explain the significance of maintaining a steep concentration gradient in the respiratory surfaces of animals. (lmk) ............................................................................................................................................................ ............................................................................................................................................................ 3. The diagram below is an apparatus used in Biology research a) Identify the apparatus and state its function Identity (1mk) ……………………………………………………………………………………………… Function (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… b) State one precaution while carrying out research using the apparatus (1mk) ………………………………………………………………………………………… ………………………………………………………………………………………….. 4. Study the diagram below and answer questions that follow (a) State the division the organism belongs (1mk) ........................................................................................................................................... (b) Name the parts labelled K and L (1mk) K..................................................................... L..................................................................... (c) What is the function of the part labelled M. (1mk) M.......................................................................................................................... 5. What is the role of heparin in blood? (1mk) ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… 6. State two importance of water in germination (2mks) ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… 7. (a) What happens to excess fatty acids and glycerol in the body. (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… 8. Tar present in burning tobacco has been found to be carcinogenic leading to lung cancer. a. Name a plant waste product that can be used in lung cancer therapy. (1 mark) …………………………………………………………………………………………………… b. State two means of lung cancer treatment. (2 marks) ………………………………………………………………………………………..………….. …………………………………………………..………………………………………………… 9. (i) Explain two ways in which the excretory system adapts the desert rat to water conservation. (2 marks) …………………………………………………..……………………………………………….… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… (ii). Give the functions of the following parts of human eye: (a) Lens (1mk) ……………………………………………………………………………………………… . (b) Ciliary body. (1mk) ……………………………………………………………………………………………… 10. a) Explain the roles of the following plant hormones (2mks) i) IAA ……………………………………………………………………………………… ii) Gibberellins ……………………………………………………………………………………… c) Name one plant hormone responsible for germination of seeds (1mk) …………………………………………………………………………………………. Temperature (oC) 10 20 20 40 50 60 Rate of respiration P C D 11. The graph below shows the effects of temperature on the rate of reaction of the enzymes salivary amylase (a)(i) Account for the changes in the curve between C and D (2mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… (ii) What does the dotted line represent? (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… 12. A student wrote the scientific name for fungus causing potato blight as phytophthora Infestans. State two mistakes made by the student while writing the name (2mks) ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… 13. After a person had swum the length of a pool and climbed out of the water their skin temperature is likely to be very low but their deep body temperature is likely to be normal Why is the skin surface likely to be cold for some-time after leaving water? (2 marks) ................................................................................................................................................ ................................................................................................................................................ ................................................................................................................................................ 8 065 14. The graph shows pressure changes in the left atrium and in the left ventricle during the heart beat. What is the state of the following valves at time x (i) Semi lunar valve in the aorta (1 mark) ............................................................................................................................................................ ............................................................................................................................................................ (ii) Bicuspid valve (1 mark) ............................................................................................................................................................ ............................................................................................................................................................ 15. a. What is asexual reproduction (1mark) ……………………………………………………………………………………………… ……………………………………………………………………………………………. b. Name any two forms of asexual reproduction (2marks) ……………………………………………………………………………………………… ……………………………………………………………………………………………… 16. Name the hormone responsible for development of secondary characteristic in females (1mk) …………………………………………………………………………………………….. 17. The diagram shown below shows representation of one organism in the five kingdoms. Examine it carefully and answer the questions that follow C:\Users\THIS PC\AppData\Local\Microsoft\Windows\INetCache\Content.Word\Screenshot_2024-07-08-19-13-44-68_6012fa4d4ddec268fc5c7112cbb265e7.jpg retort flask germinating seed germinating seed sodium hydroxide sodium hydroxide a. Identify the organism (1mark) …………………………………………………………………………………………….. b. Name the Kingdom in which the above organism belongs (1mark) ……………………………………………………………………………………………… 18. The diagram below shows an experiment that was set up to investigate germinating seeds. Beginning of experiment End of experiment (a) What changes are observable at the end of experiment? (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… (b) Explain the change observed in (a) above. (2mks) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… (c) Name the chemical process being investigated. (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… 19. Define the following terms a) Mycology (1mk) ………………………………………………………………………………………… ……………………………………………………………………………………….. b) Binomial nomenclature (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… 20. Name two organism that form lichens (2marks) ……………………………………………………………………………………………… ……………………………………………………………………………………………… 21. (a)Name one example of a characteristic in man transmitted by multiple alleles. (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… (b). What are the vestigial structures? (1 mark) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… 22. Name the tough fibrous band of connective tissue that holds the bones together at a moveable joint (1mk) ……………………………………………………………………………………………… …………………………………………………………………………………………… 23. The diagram below illustrates the life cycle of a certain member of Division in kingdom Plantae. Study it and answer the questions that follow. (a). State the name given to this type of life cycle (1mk) ………………………………………………………………………………………………… (b) Identify the dominant generation in the fern represented by the life cycle above (1mk) ………………………………………………………………………………………… (c) State another division in which such a life cycle is present (1mk) ………………………………………………………………………………………………… 24. The diagram shows the percentage of tongue rollers and non-rollers in a human population. (i)what name is given to this type of variation? (1mk) ……………………………………………………………………………………………………… (ii) Give two features of the above named type of variation (2mks) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… 25. Study the genetic cross illustrated below and answer the questions that follow. When F1 was selfed 1064 plants were counted. State the ; (i) Genotypic ratio of F2 plants (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… (ii) Number off tall plants and short plants in F2 generation (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… 26. It is known that weight lifting exercises in men causes muscles to grow bigger. However, the children of such men are not born with big bulging muscles. Explain (2mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… 27. (a) State two features of nerves which increases the speed of nerve impulse transmission along them (2mks) ……………………………………………………………………………………………… …………………………………………………………………………………………… (b). Distinguish between pyramid of numbers and pyramid of biomass (2mak) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… 28. The diagram below shows the human brain. Give the significance of the folds on the surface of the part labeled E (1mk) ……………………………………………………………………………………………… ……………………………………………………………………………………………… Which labeled parts of the brain are involved in the following activities (2mks) (a) Gasping for air after holding breath for sometime ……………………………………………………………………………………………… (b) Ability to memorize and recite a poem during music festivals ……………………………………………………………………………………………… 29. Explain what causes the tendrils of a pea plant to coil around stems of other plants.(3mks) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… 30. State two structural differences between biceps muscles and muscles in the arteries in a human being. (2mks) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… …………………………………………………………………………………………….. 31. Plants with non woody stems have various devices of getting support. State three methods by which this is achieved. (3mks) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… 32. The diagram below illustrates the results obtained in an experiment done to investigate a certain physiological process. (a) Account for the results in set up; (i) A (2mks) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… (ii) B (2mks) ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… THIS IS THE LAST PRINTED PAGE