Biology Paper 1 Questions and Answers - Murang'a County Mocks 2020/2021

INSTRUCTIONS TO CANDIDATES

• Answer ALL questions in the spaces provided.
• All workings must be clearly shown where necessary.

QUESTIONS

1. State  three activities of the cell that are controlled by the nucleus (3mks)
2. The graph below represents the growth pattern of animals in a certain phylum.
   
   
   1. Name the type of growth curve shown above. (1mk)
   2. 
      
      1. Identify the process represented by X. (1mk)
      2. Name the hormone responsible for the process in b(i) above.  (1mk)
   3. State the importance of the growth of a pollen tube to a plant. (1mk)
3. Name the causative agent of the following diseases in human (3mks)
   
   1. Amoebic dysentery
   2. Bilhazia
   3. Typhoid
4. Give three reasons why plants do not require specialized excretory organs (3mks)
5. An experiment was set up as shown below 
   
   The set up was left for 30 minutes.
   
   1. State the expected results (1mk)
   2. Explain your answer in (a) above (3mks)
6.  
   1. What is the function of Sodium hydrogen Carbonate that is added to test solution of non-reducing sugar.  (1mk) 
   2. The equation below represents a process X which is controlled by enzymes.
      
      C₆H₁₂O₆ + C₆H₁₂O₆   ⇌   C₁₂H₂₂O₁₁ +H₂O
      Glucose + Fructose           Sucrose  +  Water    
      
      1. Name the process X and enzyme R
         Process  X  (1mk)
         Enzyme R  (1mk)
7. 
   
   1. What is the importance of the counter current flow in the exchange of gases in a fish. (2mks)
   2. State two ways in which the tracheoles of an insect are adapted to their functions.  (2mks)
8. List down four phenotypic characteristics that have been selected for the production of strains suitable for modern agricultural purposes. (4mks)
9. State the branch of Biology that deals with: (2 marks)
   1. Study of birds
   2. Study of the chemical composition of organisms
10. A certain mammal has no incisors, no canines, 6 molars and 6 premolars on the upper jaw. It has 6 incisors, 2 canines, 6 premolars and 6 molars on the lower jaw.
    1. Write its dental formula (1 mark)
    2. Suggest with reasons the possible mode of feeding of the animal. (2 marks)

11. 1. Some herbaceous plants have very little strengthening tissue yet they remain firm and upright. Give a reason for this observation. (1 mark)
    2. Name the strengthening material in the following tissues. (2 marks)
       
       1. Collenchyma
       2. Xylem vessels
12. State two functions of Aerenchyma tissue in plants.  (2 marks)
13. A woman gave birth to a child of blood group B+ (B positive). Name two antigens that determined the child’s blood group. (2 marks)
14. In an experiment to investigate an aspect of digestion, two test tubes A and B were set up as shown below.
    
    
    1. The test tubes were left in the warm water bath for 30 minutes. The contents of the test tubes were tested for starch using Iodine solution.
       State the observations in: (2 marks)
       Test tube A
       Test tube B
    2. Account for the results in (a) above. (2 marks)
15. Explain each of the following
    
    1. Variegated plants accumulate less food than non-variegated plants under similar conditions.(1mark
    2. Most leaves are thin with broad leaf surface. (1mark)
    3. State three importances of photosynthesis in an ecosystem. (3marks)
16. Wing of an insect, wing of a bird, hand of a man, flipper of a whale, foreleg of a horse are locomotory structures in animals. Using the structures listed above state the ones considered as
    
    1. Homologous structures (1mark)
    2. Identify the type of evolution that brings about homologous structures. (1mark)
17. A certain plant was found to have the following features
    Parallel venation of leaves
    Sheath like petiole
    Flower parts in multiple of three
    1. Name the class to which the plant belongs. (1mark)
    2. Suggest the expected arrangement of vascular bundle in the stem of the plant.  (1mark)
18. Explain the reason for each of the following in flowering plants
    1. Wind pollinated flowers produce large number of pollen grains. (1mark)
    2. Insect pollinated flowers have small sticky stigmas that an firmly attached to the style. (2marks)
19. The following is part of a kidney nephron,
    
    
    1.  
       1. Name the process represented by the arrows (1mk)
       2. Name the conditions necessary for the process named in (a)(i) above to take place (2mks)
    2. Name one blood component present in the figure above  (1mk)
20. 
    
    1. what is seed dormancy (1mk).
    2. state two ways in which seed dormancy can be broken (2mks)
21. Explain why several lateral buds sprout when a terminal bud in a young tree is removed.  (3mks) 
22. Below is a diagram of an organelle that is involved in aerobic respiration.
    
    
    1. Name the organelle (1mark)
    2. Name the parts labeled;
       A (1mark)
       B (1mark)
       C (1mark)
    3. What is the purpose of the in-foding labeled D? (1mark)
    4. Give the mechanical compound which is formed in the organelle and forms the immediate source of energy (1mark)
23. State the function of the following parts of a light microscope
    
    1. Clip (1mark)
    2. Eye piece lens (1mark)
    3. When focusing under high power objective lens the coarse adjustment knob should never be used for focusing. Explain (2marks)
24.  
    1. Name two defects of the circulatory system in humans. (2marks)
    2. Explain two protective functions of mammalian blood.  (3marks)

MARKING SCHEME

1.  
   • cell division
   • Cell growth
   • Protein synthesis
   • Cell respiration
   • Cytoplasmic streaming
   • Cell secretion/excretion
2.  
   1. Intermittent growth curve;
   2.  
      1. Growth;
      2. Ecdysone/ mounting hormone;
   3. Results in fertilization by conveying the male gametes to the female gamete; rej. It carries/transport/medium
3.  
   1. Salmonelatyphi
   2. Entamoebahistolytica
   3. Schistosomamansoni
4. • Waste products in plants are mainly made from carbohydrate which are not as harmful as those from the protein materials.
   • Waste products are formed slowly /little accumulation of wastes / plants are less active; wastes such oxygen and carbon (iv) oxide are re-usable / recycled;
   • Some wastes such a gum and resin are stored in insoluble forms in dead tissue;
   • Some wastes can be removed by diffusion;
5.  
   1. Visking tubing in volume /bulge/swell/expand res. Turgid
   2. Water move from the beaker to the visking tubing by osmosis through semi-permeable membrane. Sucrose in the visking tubing is hypertonic to water in the beaker.
6.  
   1. Neutralise excess acid (Hcl); rej. Without excess.
   2. X – Condensation;
      R – Sucrase/ invertase;
7.  
   1. Maintains a steep concentration gradient across the respiratory surface; ensuring  maximum extraction of oxygen from water to the blood;      rej. Without steep concentration gradient (2mks)
   2.  
      • Thin epithelium for faster/ rapid diffusion of gases; rej. Without fast/ rapid
      • Have tracheole fluid/ moist surface to dissolve gases in solution before diffusing;
      • Highly branched to increase surface area for gaseous exchange; (mark first two)
        Rej. Highly vascularised
        Thin wall for epithelium
8.  
   • Resistance to diseases.
   • Early maturity
   • Adaptations to local conditions
   • High yields
   • Increased length of production
9.  
   1. ornithology;
   2. Biochemistry;
10.  
    1. 
       
    2. Herbivorous; No incisors and canines on the upper jaw;
11.  
    1. Herbaceous plants absorb water through osmosis, parenchyma cells become turgid and plants gain support by turgor pressure;
    2.  
       1. Cellulose and pectins; 
       2. Lignin;
12.  
    • Maintaining buoyancy;
    • Storage tissue;
13.  
    • Antigen B;
    • Rhesus antigen;
14.  
    1. Test tube A   - Brown colour of iodine solution remains;
       Test tube B   - Blue -black colour observed;
    2. In test tube A, starch was broken down by action of salivary amylase in saliva to maltose; while in test tube B, the enzyme salivary amylase in saliva was denatured by boiling;the beaker to the visking tubing by osmosis through semi-permeable membrane. Sucrose in the visking tubing is hypertonic to water in the beaker.
15.  
    1. Variegated leaves have less chlorophyll hence synthesize less food while non-variegated leaves are entirely green with more chlorophyll hence synthesize more food; 1mk
    2.  
       • Thin membrane enhance easy diffusion of carbon (IV) oxide;
       • Broad leaves increases surface area for photosynthesis process; 1mk
    3.  
       • Production of food;
       • Production of oxygen;
       • Removal of carbon (IV) oxide from the air; 3mks
16.  
    1. • Wing of a bird, hand of a man, flipper of a whale and foreleg of horse; 1mk
         NB Mark as a whole
       • Wing of an insect and of a bird;  1mk
    2. Divergent; 1mk
17.  
    1. Monocotyledonae
    2. Vascular bundles are randomly scattered within the cortex;    1mk
18.  
    1. To increase the chances for pollination; 1mk
    2. So that the pollen grains on the insect’s bodies stick onto them; firmly attached to avoid any breakage when the insect makes contact; 2mks
19.  
    1.  
       1. Ultra filtration
       2. sufficient pressure to force the filtrate through pores in the endothelium of  glomeruli and epithelium of Bowman’s capsule to allow selective filtration.
       3.  
          • urea
          • Glucose
          • Amino acids
          • salts.
20.  
    1.  inability of seed to germinate despite all the conditions necessary for germination being provided.
    2.  
       • scarification
       • Removing germination  inhibitors
       • Allow embryo to mature before planting
       • Increase concentration of hormones which stimulate germination
21. High auxin concentration produced by terminal bud/ apical meristem, inhibits lateral buds growing into branches; removal of terminal bud/ apical bud lowers the concentration of auxins/ lowers the inhibition effect (hence sprouting of lateral buds; Rej without high concentration
22.  
    1. Mitochondrion; 1mk
    2. A – outer membrane;
       B- inner membrane;
       C – matrix; 3mks
    3. Increase the surface area over which respiration takes place; 1mk
    4. Adenosine Triphosphate (ATP);     1mk
23.  
    1. 
       
       1. Hold the specimen on the slide to keep it in a firm position; 1mk
       2. Contributes to the total magnification of the specimen together with the objective lens; 1mk
    2. The coarse adjustment knob moves the body tube over longer distances; it would easily cause the objective lens to hit/tough the slide and cause destruction of both slide and lens; 2mks
24.  
    
    1.  
       • Thrombosis; Accept coronary thrombosis;
       • Cerebral thrombosis
       • varicose veins;
       • High blood pressure/Hypertension;
       • Arteriosclerosis; 2mks
    2.  
       • Platelets initiates blood clotting on damaged vessel. The clot prevents entry of pathogenic micro-organisms;
       • Some white blood cells (Phagocytes) engulf and digest pathogens thus protecting the body against pathogens;
       • Lymphocytes secretes antibodies that destroy pathogens and their secretions; max 2mks