Biology Paper 1 Questions and Answers - Kigumo Mocks 2021 Exams

QUESTIONS

1. Differentiate nutrition in plants from that in animals. (2 marks)
2. State and explain three modes of feeding in animals. (3 marks)
3. Name two properties of disaccharides. (2 marks)
4. Explain three adaptations of arteries to their function. (3 marks)
5. Explain what happens during photolysis? (3 marks)
6. An experiment was set up as shown.
   
   
   1. State and explain what happened to visking tubings in both M and N. (4 marks)
   2. What does visiting tubing correspond to in a living organism? (1 mark)
7. State three digestive enzymes present in pancreatic juice. (3 marks)
8. Colour blindness is a condition carried by a recessive gene on X-chromosome. A colour blind man married a homozygous normal woman. One of their daughters married a normal man. Using letter c for colour blindness,
   1. Work out the outcome of the daughter's marriage. (4 marks)
   2. Why is colour blindness more common in men than women? (2 marks)
9. The figure below shows the iris of a mammalian eye.
   
   
   1. Label the parts A, B and C. (3 marks)
      1. ................................................................
      2. ................................................................
      3. ................................................................
   2. State three adaptations of the iris to its function. (3 marks)
10. The diagram below shows a stem twining round a support.
    
    
    1. Explain how this phenomenon occurs (3 marks)
    2. Explain three biological significance of this phenomenon. (3 marks)
11.  The base sequence on a DNA strand was as follows;
    A --- T --- A --- A ---- C ---- G --- G ---- T ---- A
    1. Write the sequence on the other strand. (1 mark)
    2. Write the base sequence on RNA strand replicated from the DNA. (1 mark)
12. Explain four adaptations of hydrophytes to their habitat. (4 marks)
13.                  
    1. List three differences between the nervous system and the endocrine system. (3 marks)
    2. Name two transmitter substances found in the synapse. (2 marks)
14. Explain four roles of water in seed germination. (4 marks)
15.                
    1. Name two plant cells where you would expect to have numerous mitochondria. (2 marks)
    2. State one role of nucleolus. (1 mark)
16. Explain three adaptations of the sperm cell to its function. (3 marks)
17. The diagram below shows arrangements of bones on human forelimb.
    
    
    1. Name bones A and B. (2 marks)
       1. ................................................................
       2. ................................................................
    2. State two roles of the structure labelled C (2 marks)
    3. Name the part that articulates with bone labelled B at part E. (1 mark)
    4. Name the type of joint forms at the part labelled D. (1 mark)
18.                    
    1. State two special properties of the cardiac muscles found in mammalian heart. (2 marks)
    2. Name three organ systems in human body where smooth muscles are found. (3 marks)
19. State three unique characteristics of members of the class Crustacea. (3 marks)
20. Industrial wastes may contain metabolic pollutants. State how such pollutants may indirectly reach and accumulate in the human body if the wastes were dumped into rivers. (3marks)
21. State three biotic factors that affect distribution of living organisms in an ecosystem. (3marks)

MARKING SCHEME

1. Plants make own food,(autotrophic); while animals take ready-made food,(heterotrophic);
2.                    
   • Carnivorous-feed on flesh;
   • Herbivorous- feed on vegetation/plants;
   • Omnivorous-feed on both flesh and vegetation;
3.                    
   • soluble in water;
   • sweet tasting;
   • crystalline;
4.            
   • Have narrow lumen to maintain high blood pressure;
   • Have a thick elastic wall to help blood flow;
   • Have no valves so blood flow is not inhibited;
5. Water molecule; is split by light energy; into hydrogen ions and oxygen gas;
6.                    
   1. M- decreased in size;
      • distilled water is hypotonic; so water molecules mover into salt solution by osmosis;
      • N- Decreased in size;
      • Salt solution is hypertonic; so water molecules moved out of tubing by osmosis;
   2. cell membrane;
7.                  
   • Pancreatic amylase;
   • Pancreatic lipase;
   • Trypsin;
8.                    
   1.  
   2. All men with the gene are colour blind; women with one gene are normal but carriers;
9.                  
   1. A- Circular muscle;
      B- Radial muscle;
      C -pupil;
   2.                    
      • pigmented to absorb light controlling amount entering;
      • has radial and circular muscles to control size of pupil controlling amount of light entering eye;
      • it gives the eye colour;
10.                
    1. Auxin; moves away from point of touch; causing faster growth on other side; resulting in coiling growth;
    2.              
       • expose leaves to light for photosynthesis;
       • expose flowers to agents of pollination;
       • expose fruits and seeds to agents of dispersal;
11.                    
    1. T --- A ---- T----T ---- G ---- C ---- C ---- A ---- T;
    2. U ----A --- U ---- U ---- G ---- C ---- C --- A ---- U;
12.                  
    • Roots with no root hairs to reduce absorption;
    • Numerous stomata on upper surface of leaves to increase transpiration;
    • Large air spaces to increase buoyancy;
    • Large leaves to increase surface area exposed for transpiration increase;
13.              
    1.                  
       

       Nervous	Endocrine
       Nerve impulse evoke response	Chemical evoke a response;
       Transmitted through neurones;	Transmitted through blood;
       Response is rapid	Response is slow;
       Effect short lived	Effect is long lasting;

    2.               
       • Noradrenaline;
       • Acetylcholine;
14.                      
    • Activate germination enzymes;
    • Hydrolyses stored food;
    • Transport food to embryo;
    • Dilute germination inhibitors;
    • Soften the seed coat;
15.                        
    1.           
       • Root hair cells;
       • Companion cell;
       • cells in meristematic tissue;
    2. Formation of ribosomes;
16.                  
    • Has acrosome containing lytic enzymes that digest egg membrane;
    • Has a long tail for swimming to the ovum;
    • Has numerous mitochondria to provide energy for swimming to the ovum;
    • It's streamlined in shape for minimum resistance to movement;
17.                      
    1. A- radius;
       B- Humerus;
    2. Attachment of triceps muscle;
       Prevent overstretching of the arm;
    3. Glenoid cavity;
    4. Glinding joint;
18.                
    1.                
       • They are myogenic;
       • Contract and relax continuously without fatigue;
    2.                
       • Digestive system;
       • Reproductive system;
       • Circulatory system;
    3.                
       • Have a carapace;
       • Have two pairs of antennae;
       • Have five pairs of legs;
19. Pollutants are absorbed by aquatic plants; which are eaten by primary consumers e.g. fish; man accumulates the pollutants by eating fish regularly;
20. Competition;
    Predation;
    Parasitism;
    Saprophytism;
    Symbiosis;