Biology Paper 1 Questions and Answers - Form 3 End Term 2 Exams 2022

QUESTIONS

1. State three ways in which protein are important to plant. (3marks)
2. The diagram below represents a cell organelle.
   
   
   1. Identify the organelle. (1 mark)
   2. Name the part labeled B. (1 mark)
   3. State the function of part labeled A. (1 mark)
3. Define binominal nomenclature. (1marks)
4. Name any two problems that animal species overcome by their dispersion. (2marks)
5. Explain why tropical  forests do not have undergrowth (2marks)
6. How is blood pressure generated and maintained in a vein? (2marks)
7. What is the function of catalase? (2marks)
8.         
   1. State the important of cross-pollination to flowering plants. (1mark)
   2. How is self-pollination a disadvantage to flowering plants? (1mark)
9. What is the role of light energy in autotrophic nutrition in spermatophyte? (2 marks)
10. How is fur important to desert animal, other than in the regulation of their body temperature? (1mark)
11. What are the functions of named product of white blood cells? (3 marks)
12. Explain three adaptations of cardiac muscles to their function. (3 marks)
13. A form one student trying to estimate the size of onion cells observed the following on the microscope’s field of view.
    
    
    1. Define the term resolving power. (1 mark)
    2. If the student counted 20 cells across the field of view calculate the size of one cell in micrometers. (2 marks)
14. What is tidal volume in ventilation in man? (1mark)
15. Define peristalsis and state its importance in the nutrition of mammals. (2 marks)
16. The diagram below shows part of plant tissue.
    
    Name cell labeled X and part labeled W. (2 marks)
17. Why is the liver part of the digestive system? (2 marks)
18. State the importance of cytoplasmic filaments in sieve tube elements. (1 mark)
19. State any two characteristics of populations. (2marks)
20. Describe any two functions of mitosis? (2 marks)
21. The diagram below shows the exchange of gases in alveolus.
     
    1. State how the alveoli are adapted to their function. (3 marks)
    2. Name the cell labeled A. (1 mark)
22. What are the external conditions needed, by root hair cells, for the uptake of mineral salts ions from the soil? (2 marks)
23. The diagram below represents a pyramid of biomass derived from a certain ecosystem
     
    1. Suggest the type of ecosystem from which the pyramid was derived (1mk)
    2. State the significance of short food chains in an ecosystem (1mk)
24. Suggest two reasons for the appearance of glucose in the urine of a man. (2 marks)
25.      
    1. State the source Carbon (IV) oxide in aquatic ecosystems. (2 marks)
    2. State the importance of Carbon (IV) oxide to aquatic ecosystems. (2 marks)
26. The set up below shows apparatus to demonstrate a certain biological process
    
    
    1. What biological process was being investigated in the experiment (1mk)
    2. Write down a word equation that represents the reaction above (1mk)
    3. In the above set up, why was it important to boil and cool glucose before adding yeast? (1mk)
27. What is the homeostatic importance of cuticles of leaves? (2marks)
28. Outline two functions of parenchyma cells in herbaceous plants. (2 marks)
29. What is the important of diffusion to red blood cells? (2marks)
30. The diagrams below show a pair of homologous chromosomes. Study them and answer the questions that follow.
    
    
    1. State the phenomenon shown above (1mk)
    2. What is the genetic significance of the phenomenon above? (2mks)
31. Account for the thick wall and narrow lumen of an artery. (2marks)
32. How do pathogens that enter the body through the respiratory tract in man prevented from causing diseases? (1mark)
33. Where does the detoxification of ammonia take place in mammals? (1mark)
34. Name the processes that take place in the grana of chloroplast. (2marks)
35. The experiment illustrated below was set up to investigate a certain physiological process using a raw tuber
    
    
    1. Suggest a possible physiological process that was being investigated (1mk)
    2. Explain the results obtained in the above experiment after a few hours (2mks)
    3. State the observations that would have been made if the experiment was repeated using boiled potato (2mks)
36. Name the causative organism of the following diseases
    1. Malaria (1mk)
    2. Bilharzia (1mk)

MARKING SCHEME

1. The formation of (plant) enzymes; The formation of pigments /chlorophyll; The formation of (plant) hormones / Auxins; The formation of tissues; stored as  food reserves (3marks)
2.      
   1. Mitochondrion rej mitochondria; (1mk)
   2. Cristae; (1mk)
   3. Site where respiration occur;
      harbors respiratory enzymes] (any one) (1mk)
3. System of naming where a species is assigned two scientific names i.e genus and the specific name.
4. Reducing can petition; preventing inbreeding; reducing the spread of epidemics; (2marks)
5. Light energy is prevented from reaching seedling; they die before they can photosynthesis as they use up all food reserves; (2marks)
6. Skeletal muscles contract to press at the blood is veins; the valves prevent the pressure from being drawn backwards; (2marks)
7. It catalyzes /speeds up the breakdown of hydrogen peroxide; to harmless water and oxygen (2marks)
8.    
   1. It brings about genetic mixing / variation and so improves hybrid vigour /survival value (1mark)
   2. Undesirable traits are transferred to progeny reducing the capacity to survive adversity. (1mark)
9. It photolysis water; to produce hydrogen ions needed in carbon (IV) oxide fixation (2marks)
10. It provides camouflage it provides the animals with a definitive pigment (1mark)
11. Agglutinins clump bacteria for phagocytosis Antitoxins denature neutralize poisons. Antibodies dump to bacteria, preventing their activity , opsonins adheres on the surface of the pathogens, lysins digests the cell membrane of the pathogen for the phagocytes to engulf (3marks)
12. They are highly branched for rapid transmission of impulse; 
    The have intercalated disc for rapid transmission. They do not fatigue / do not form lactic acid
13.      
    1. Resolving power is the ability to distinguish two close parts as separate entities; (1mk)
    2. Diameter of field of view = 3mm
       No of cells 20 cells
       1mm = 1000μm
       3mm = 3000μm;
       Size of 1 cell = 3000 = 150μm; (2mks)
                                 20
14. The amount of air taken in exchanged in one breath. (1mark)
15.      
    1. The rhythmic contraction of alimentary canal muscles; it moves food along (the lumen of) the canal (2marks)
    2. Provides a large surface area for reabsorption of water ions (2marks)
16.      
    1. X – Guard cell;
       W – Stoma; rej. Stomata
    2. Have chloroplasts that help in the process of photosynthesis;
    3. Have thin outer wall and thick inner wall to enhance bulging during opening of stomata
17. It secrets bile; which is needed in the classification of lipids; and neutralizing of Hydrochloric acid) (2marks) (2marks)
18. The provide space for cytoplasm streaming in the translocation of nutrients. (1mark)
19. Population density, dispersion
20. Forms the basis for asexual reproduction, involved in repair of worn out tissues/ cells, involved in growth and development
21.      
    1.      
       • Have thin film of moisture to dissolve gases for efficient diffusion;
       • Have a thin epithelium for faster diffusion of gases;
       • Have a large surface area for maximum gaseous exchange;
       • Have a network of blood capillaries for transportation of differing gases; (any three) (3mks)
    2. Red blood cell; (1mk)
22. The growth of an organism due to cell fertilization; healing of wounds; cell replacement of epidermal tissues (2marks)
23.      
    1. Aquatic ecosystem
    2. The shorter the fluid chain, the more energy can be derived from it, hence the larger the population it can support
24.      
    1. The different forms of a gene (1mark)
    2. The ABO blood groups in man (1mark)
25. Crossing-over in meiosis I; genetic mixing during fertilization; mutations of genes; the environment of the species; (3mks)
26.      
    1. Gas produced during anaerobic respiration
    2. Glucose Ethanol + Carbon (IV) oxide +Energy
    3. To remove O₂; cooling to provide suitable temperature for enzymatic reactions/ avoid destroying/killing yeast
27. The availability of oxygen for respiration energy production; A concentration gradient of salt ions in the soil (2marks)
28. Lack/limited production of insulin by pancreas; injury to the Bowman’s capsule allowing free flow of glucose (2marks)
29.      
    1. The cells divide mitotically to increase length (1mark)
    2. Auxins stimulate cell division  mitosis and cell elongation) (1mark)
30.    
    1. Crossing over
    2. Variations; which may lead to new genetic fruits either advantages or disadvantages to the organism/may lead to evolution
31. To carry the blood from the heart which is flowing under very high pressure (2marks)
32. The trachea is ciliated to trap the dust particles and other foreign materials (2marks)
33. Liver (2marks) 
34. Photolysis, conversion of light energy into chemical energy( ATP)(2marks) 
35.      
    1. Osmosis
    2. The amount of sucrose solution increase; the sucrose solution has higher osmotic pressure hence passes into the potato cavity.
    3. There would be no movement of water; because the protoplasm is killed by boiling, hence the semi-permeable membrane. (1marks)
36.      
    1. Plasmodium sp
    2. Schistosoma sp