KCSE 2011 Biology Paper 1 Questions with Marking Scheme

1. Name two kidney diseases. (2 marks)
   
   
2. 1. Write the dental formula of an adult human. (1 mark)
   2. Name two dental diseases. (2 marks)
      
      
3. Give three reasons for classifying organisms. (3 marks)
   
   
4. State one use for the following apparatus in the study of living organisms.
   1. Pooter (1 mark)
      
      
5. The figure below illustrates a food web in a certain ecosystem.
   
   
   
   
   
   From the food web:
   
   
   1. Draw the shortest food chain; (1 mark)
      
      
   2. Identify the organisms with the highest
      1. Number of predators; (1 mark)
      2. Biomass. (1 mark)
         
         
6. What is meant by the following terms?
   1. Ecology. (1 mark)
   2. Carrying capacity. (1 mark)
      
      
7. The diagrams below show an experimental set-up to investigate a certain process in a plant tissue.
   
   
   
   
   
   Explain the results obtained after 30 minutes. (4 marks)
   
   
8. State three characteristics of the class crustacean. (3 marks)
   
   
9. The diagrams below illustrate the organs of some flowering plants.
   
   
   
   
   
   State the classes to which the plants belong. (2 marks)
   A ……………………………………………………………………
   B ……………………………………………………………………
   
   
10. 1. Give two differences in the products of anaerobic respiration between plants and animals. (2 marks)
    2. Name the site of anaerobic respiration in a cell. (1 mark)
       
       
11. State the functions of the following parts of a light microscope. (2 marks)
    Fine adjustment knob
    Stage
    
    
12. The diagram below represents a certain organism
    
    
    
    
    State the phylum and class to which it belongs. (2 marks)
    Phylum ……………………………………………………………..
    Class ………………………………………………………………..
    
    
13. State two functions of carbohydrates in the human body. (2 marks)
    
    
14. The diagram below represents a certain plant.
    
    
    
    
    1. What is the likely habitat for the plant? (1 mark)
    2. Give two reasons for your answer in (a) above. (2 marks)
       
       
15. Give reasons for carrying out the following procedures when preparing temporary wet mounts on plant tissues.
    1. Making thin plant sections. (1 mark)
    2. Adding water on the plant section. (1 mark)
    3. Placing a cover slip over the plant section. (1 mark)
       
       
16. 1. Describe the condition know as varicose veins. (2 marks)
    2. What is the role of blood platelets in the blood clotting process? (2 marks)
       
       
17. The diagram below represents part of the human digestive system.
    
    
    
    
    1. Name the organs labeled L and M (2 marks)
       L …………………………………………………
       M ……………………………………………….
       
       
    2. 1. Name the substance produced by the organ labeled K. (1 mark)
       2. State the function of the substance named in b(i) above. (1 mark)
          
          
18. 1. Name one salivary gland in humans. (1 mark)
    2. State two functions of saliva. (2 marks)
       
       
19. 1. Apart from lungs, name two gaseous exchange surfaces in the frog. (2 marks)
    2. Write an equation that summarizes the process of aerobic respiration. (1 mark)
       
       
20. The number of stomata on the lower and upper surfaces of two leaves from plant species X and Y were counted under the field of view of a light microscope. The results were as shown in the table below.
    
    
    
    
    1. Which of the two leaves would be expected to have a lower rate of transpiration? (1 mark)
    2. Give a reason for your answer in (a) above. (1 mark)
       
       
       
21. 1. What is meant by convergent evolution? (1 mark)
    2. State two limitations of fossils as an evidence of evolution. (2 marks)
       
       
22. State the difference in content of oxygen and carbon (IV) oxide in the air that enters and leaves human lungs. (2 marks)
    
    
    
23. The diagram below represents a transverse section of an ovary from a certain flower.
    
    
    
    1. 1. Name the structure labelled W. (1 mark)
       2. Name the type of placentation illustrated in the diagram. (1 mark)
          
          
          
    2. Give an example of a plant whose flowers have the type of placentation named in (a)(ii) above. (1 mark)
       
       
       
24. 1. Differentiate between the following terms
       1. Dominant and recessive gene; (1 mark)
       2. Continuous variation and discontinuous variation. (1 mark)
          
          
    2. What would be the expected results from a test cross? (2 marks)
       
       
25. State one economic importance of each of the following plant excretory products. (3 marks)
    
    
    1. Tannin
    2. Quinine
    3. Caffeine
       
       
26. Name the gamete cells that are produced by the ovaries. (1 mark)
    
    
27. The diagram below represents features of a joint in a mammal.
    
    
    
    
    
    1. Name the part labeled A. (1 mark)
    2. State the function of the part labeled B. (1 mark)
       
       
28. 1. What is a tropic response?
    2. State two ways by which auxins regulate growth in seedlings. (2 marks)
    3. State four reasons why water is significant in seed germination. (4 marks)

MARKING SCHEME

1.    
   1. Nephritis;
   2. kidney stones; (2 marks)
2.          
   1.  i  2  c  1  pm  2  m 3 (1 mark)
          2     1         2       3
   2. Dental carries;
      Periodontal/gingivitis/pyorhoea;
      (2 marks)
3.     
   1. Identify similarities and differences between organisms;
   2. Organize scientific knowledge in an orderly system;
   3. Monitor emergence, presence and disappearance of organisms in and from the earth;
   4. Grouping organisms for easy study;
      (3 marks)
4.     
   1. Sucking small insects/animals;
   2. A trap into which small animals fall and get trapped;
5.     
   1. Grass → Grasshopper → Lizards;
   2.       
      1. Chicken;
      2. Grass;
6.           
   1. This is the study of the inter-relationship between organisms and their environment;
   2. The maximum population of a species than a particular habitat can support; without depletion of resources.
7. Water was hypotonic to cell sap of adjacent cells; and these cells absorbed water through osmosis; and their cell sap became less concentrated than those of the next cells; The process was repeated until water reached the sugar solution;
8. Fused head and thorax/cephalothorax often protected by a carapace; Gaseous exchange through gills; 
   Two pairs of antennae;
   |Five to twenty pairs of limbs;
   A pair of compound eyes;
   Three pairs of mouth parts (consisting of mandibles, maxillary, palp and labium) a pair of mandibles and 2 pairs of maxillae.
9.    
   1. Dicotyledonae;
   2. Monocotyledonae;
10.           
    1.         
       1. Lactic acid in animals while in plants it is ethanol/alcohol;
       2. No carbon IV oxide produced in anaerobic respiration in animals while anaerobic respiration in plants produces carbon IV oxide;
    2. Cytoplasm;
11. Moves the body tube through smaller distances to bring the image/specimen/object into sharper focus;
    Platform where specimen (on slide) is placed;
12. Chordata; Aves;
13. Source of energy; Storage materials;
14.      
    1. Dry/Arid/Semi-arid/Desert;
    2. Succulent/fleshy stem; reduced leaves/ leaves reduced into thorns/leaves modified into spines/spikes;
15.        
    1. To reduce layers of cells to allow light to pass through;
    2. To make the cells turgid/prevent drying up;
    3. To protect the lens on the objective;
16.       
    1. Weakened/defective valves in veins; causing blood/body fluid to accumulate; leading to swelling.
    2. When exposed to air they disintegrate/rupture/burst; releasing thromboplastin; thrombokinase
17.      
    1. L - Duodenum;
       M - Pancreas;
    2.               
       1. Bile;
       2. Emulsification/emulsifies fats;
       3. Provides alkalinic medium for enzyme action.
       4. Neutralizes acidic chyme.
18.         
    1. Sublingual gland; submaxillary gland; parotid gland; submandibular
    2. Lubricating food; digestion of starch; moisten food; provide alkaline medium;
19.             
    1.          
       1. Skin;
       2. buccal cavity/mouth cavity
                           (enzyme)
    2. Glucose + Oxygen     →     Carbon IV oxide + water + energy;
                                (enzyme)
       C6H12O6 + 6O2      →      6CO2+6H,0 + ATP
20.             
    1. X
    2. X has fewer stomata; most stomata in leaf X are concentrated on the lower side;
21.       
    1. Where different structures evolve to perform the same function (e.g. wings of insects and birds are different in structure but are used for flying);
    2. Missing links;
       Distortion of parts during sedimentation/earthquakes/putrefication;
       Destruction of fossils by geological activities/faulting/folding;
22. Air that enters lungs has a higher content of oxygen than air that leaves the lungs;
    Air that enters the lungs has lower content of carbon (IV) oxide than air that leaves the lungs;
23.          
    1.         
       1. Ovule;
       2. Axile placentation;
    2. Orange or any correctly named citrus plant;
24.            
    1.       
       1. Dominant gene expresses itself phenotypically in both its homozygous and heterozygous states while recessive gene can only express itself phenotypically in the homozygous state;
       2. Continuous variation is a characteristic for which there is a continuum or range while discontinuous variation is a characteristic for which there are discrete categories or units;
    2. Either all offspring show the dominant characteristics; or half offspring show the recessive while the other half show the dominant characteristics;
25.         
    1. Softening of leather;
    2. Treatment of malaria/manufacture of antimalaria drugs.;
    3. Stimulant used in beverages;
26. egg/ovum/ova;
27.     
    1. Ligament;
    2. Secretes synovial fluid; contains/holds the synovial fluid in place;
28.    
    1. It is a growth movement in plants in response to a unidirectional stimulus;
    2. Accelerates growth of shoots;
       Can inhibit growth of roots;
29. Activate enzymes; provides a medium for enzymatic activities to break down stored food to soluble form; Hydrolyses; dissolves food materials; is a medium of transportation of dissolved food substances to growing regions of radicle and plumule; Softens seed coat to facilitate emergence of radicle;