Biology Paper 1 Questions and Answers - Mokasa 1 Joint Mocks Exams 2023

Instructions

• Answer all the questions
• You may be penalized for wrong spelling especially technical terms

1.  
   1. Name the type of reproduction exhibited by a prothallus. (1 mark)
   2. Briefly describe alternation of generation in a liverwort. (3 marks)
2. Name the blood vessel that contains the highest concentration of:
   1. Amino acids.   (1 mark)
   2. Carbon (iv) oxide concentration.  (1 mark)
3. Below is a sketch diagram Showing the parts of mammalian circulatory system. Use it to answer the question below it.
   
   Explain why the level of blood sugar in vessel 2 would be higher than that in vessel 3 during fasting. (3 marks)
4. In what ways do green plants compensate for their inability to move about.   (2 marks)
5. Explain how the following factors influence the rate of carbohydrate formation. 
   1. Light intensity.  (2 marks)
   2. Carbon (iv) oxide concentration.    (1 mark)
6. What is the fate of excess glucose formed by photosynthesis in Dicotyledonous plant. (2 marks)
7. Using the light microscope, a student observed and drew the organism shown below.
   
   1.  
      1. Name the kingdom to which the above organism belongs. (1 mark)
      2. Give a reason for your answer in (a) (i) above.  (1 mark)
   2. If the magnification of the objective lens was X40, work out the magnification of the eyepiece lens.       (1 mark)
8. Give the Characteristics that distinguish scientific names from common names.      (2 marks)
9. Name a vitamin manufactured by human body.    (1 mark)
10. The graph below shows the effect of substrate concentration on the rate of an enzyme catalyzed reaction.
    
    1. Account for the shape of the graph between X and Y.    (3 marks)
    2. How can the rate of reaction be increased beyond point Y.     (1 mark)
11. A farmer mated his dark red cow with a white bull. The cow gave birth to a light red calf. 
    1. State why the calf is light red and not dark red or white.   (1 mark)
    2. If a light red bull is mated with a dark red cow. Work out using appropriate symbols the probability of getting light red offspring.    (4 marks)
12. Muscle cells contain more mitochondria than adipose tissue cells. Give a reason for the observation. (1 mark)
13. State the function of the diaphragm in the light microscope.   (1 mark)
14. Name two organelles that are likely to be abundant in glandular organs.  (2 marks)
15. State two functions of a pollen tube.       (2 marks)
16. State the role of colchicine in plant breeding.     (1 mark)
17. What is biological control.    (1 marks)
18. Give a reason why two herbivores can feed on one grass without competing for it.      (1 mark)
19. Explain how cheetahs and leopards become structurally different from each other. (3 marks)
20. Explain why malaria is symptomized by passing out yellow urine.   (2 marks)
21. State two advantages of asexual reproduction over sexual reproduction.     (2 marks)
22. The equation for respiration of certain substrate is shown below.
    2C₅₁H₉₈O₆ + 145O₂ → 102CO₂ + 98H₂O
    1. Calculate respiratory quotient from the above equation.   (2 marks)
    2. With a reason identify the type of the substrate.     (2 marks)
23. Briefly describe external fertilization in frogs.      (2 marks)
24. The diagram below shows longitudinal section of a root.
    
    
    1. Label the part on the diagram where cells increase in size as A.   ( 1 mark)
    2. State two characteristics of meristematic cells.    ( 2 marks)
25. How are male secondary sexual characterstics are developed during puberty   (3 marks)
26. Show how the liver and hypothalamus co-ordinate to lower the body temperature.    (2 marks)
27. Name any two enzymes involved in germination and in each case state their specific role.  (4 marks)
28. Study the diagram below and use it to answer the questions below it.
    
    Identify the significance of the following life processes in the process occurring in A.''
    
    1. Respiration  (1 mark)
    2. Nutrition (1 mark)
29. Define the following terms as used in growth and development.     (1 mark)
    1. Parthenogenesis   ( 1mark)
    2. Parthenocarpy.     (1 mark)
30. Explain what happens to the following when put in distilled water.
    1. Amoeba.    (2 marks)
    2. Red blood cell.     (2 marks)
31. State two functions of hypocotyl in epigeal germination       (2 marks)
32. List two activities that takes place before cell elongation    ( 2marks)
33. Describe how transpiration pull is created.    ( 3 marks)

MARKING SCHEME

1.  
   1. Sexual..
   2. Sporophyte produces spores which germinate to form gametophyte, which later on Carry out fertilisation to form a Zygote; which develops into embryo which develops into Sporophyte;
2.  
   1. Hepatic portal vein.
   2. pulmonary artery.
3. During fasting there is no digestion of carbohydrate/absorption of glucose;  blood Vessel 3 lacks/ has little glucose. The liver converts glycogen/fat into glucose (which is transported by vessel 2.).
4.  
   • Manufacture their own food
   • Have roots for absorption of water and mineral salts.
   • Grow tall | support on objects to expose their leaves to light for photosynthesis.
5.  
   1. Light intensity.
      • Affects the rate of photolysis
      • Affects the rate of formation of ATP / phosphorilation.
   2. Carbon (iv) oxide concentration.
      
      • Affects the rate of CO₂ fixation/formation of simple food.
6.  
   • Some are respired.
   • Some Converted into starch for storage...
   • Some Converted into sucrose for storage.
7.  
   1.  
      1. Protoctista
      2.  
         • Unicellular/microscopic
         • Presence of flagella.
   2. Magnification = Objective lens magnification X Eye piece lens magnification
      Eye piece lens magnification = 400 = X10
                                                         40
8.  
   

   Scientific names	Common names
   Has two parts  Use latin language  Govern by rules.	Has one part. It's one  use different languages  No rules to be followed/adhered to.

9.  
   • K
   • D/calciferol
10.  
    1. Increase in substrate concentration towards optimum; leads to increase in the number of active sites./enzymes occupied by substrate, leading to increase in the rate of reactio
    2.  
       • By increasing wnzyme concentration
       • Introduction of co-factors and co-enzymes
       • Removing inhibitors
       • Provision of optimum temperature
11.  
    1. The genes for the two colours exhibit incomplete dominance/blend (mix) to come up with intermediate characteristics  (light red colour).
    2.  
       
       Probability = ½
12. Muscle cells require more energy than a adipose cells.
13. Controls light reflected to the stage/passing through the condensor
14.  
    • Secretory Vessicle (golgi Apparatus)/golgi bodies
    • Endoplasmic reticulum.
15.  
    • Carries male nuclei to the embryo sac.
    • Prevents formation of another pollen tube.
16. Induces polyploidy/non-disjunction.
17. Use of living organvilons to control the population of other.living organisms.
18. The two feed on two different parts of the grass.
19. Seperated/isolated; developed modification to adapt them to the new environments; the new characteristics were passed on to the offspring.
20. Plasmodium destroy  RBC or haemoglobin; leading to formation of urochrome.
21.  
    • Does not require agents of pollination and dispersal/ The plant depends on itself for reproduction.
    • Does not result into indiscriminate distribution of plants.
    • Maturity is reached faster.
    • Maintenance of desired characteristics
    • Offspring can survive temporary in unsuitable conditions
22.  
    1. RQ =    CO₂ produced
                    O₂ consumed
             = 102
                145
            = 0.7
    2. Lipid
       Since it's RQ is 0.7.
23. The Female lays eggs; as the male shed sperms on the eggs; 
24.  
    1. 
       
    2.   
       • Have many mitochondria
       • Thin wall
       • Dense cytoplasm
       • Lack vacuole
       • Cuboid
25. The hypothalamus sends impulses to the pituitary gland; which is stimulated to secrete Luteinising hormone that stimulate interstitial cells to release androgends/ testosterone; which stimulates development/ onset of the characteristics;
26. Hypothalamus detects and sends impulses to liver; which stimulate it to carry out endothermic reaction.
27.  
    • Diastase - break down carbohydrates to glucose.
    • Lipase - breakdown lipids to fatty acids and glycerol
    • Protease - breakdown proteins to amino acids
28.  
    1. Provides energy
    2. Provides substrate for respiration
29.  
    1. is the process in which eggs hatch/change into larvae/nymph without fertilisation.
    2. Is the process in which ovaries change into fruits without fertilisation.
30.  
    1. Absorbs water by osmosis and does not burst since it has contractile vacuole that excretes excess water.
    2. Absorbs water by osmosis and bursts since it lacks a rigid (Cellulose) Cellwall.
31.  
    • protests the plumule during germination
    • Carrier/Pusher/pulls cotyledons to the above soil surface.
    • Transports hydrolized food to the plumde.
32.  
    • The cell assimilate food. ( assimilation of food
    • The cell divide   ( cell division)
33. Mesophyll cells lose water to the substomatal space; becomes hypertonic to the adjacent cells which also lose water making them to draw water from the xylem of the leaf; which also loses water making it to draw water from the xylem of the stem; then xylem of the root.