Biology Paper 1 Questions and Answers - KCSE 2021 Westlands Mock Exams

Questions

Instructions

• Write your name, school and class in the spaces provided
• Answer all the questions in the spaces provided.
• This paper consists of 9 printed pages

1. Name two branches of microbiology (2marks)
2. Give two important functions of a fruit with regard to a plant (2marks)
3. Construct a food chain with the following: (1mark)
   Orange fruit, large bird, fruit fly, small bird
4. A student wrote the scientific name of Baobab tree as adansonia Digitata.
   1. Identify two mistakes made by the student (2marks)
   2. Identify the species name (1mark)
5. State the differences between light and electron microscopes in terms of the following: (2marks)
   1. way of illumination
   2. Source of illumination
   3. State two factors to consider the type of microscope to be used in a given biological investigation (2marks)
6. Explain how parasitism differ from predation (2marks)
7.    
   1. Explain how papain is used as a meat tenderizer in food processing industries (2marks)
   2. Name a plant excretory product that is toxic to plasmodium (1mark)
8. Distinguish between ilium and ilium (1mark)
9. Explain why Egyptian mummies are not regarded as fossils (1mark)
10. Explain what would happen to digestion and blood sugar regulation if the pancreatic duct of a mammal was blocked. (3marks)
11. Equal amounts of three different sugar solutions were placed in the visking tubings X, Y and Z. the tubings were placed in a beaker of water containing 5% sugar solution. The set up was left for two hours. The results were as shown below.
    
    
    1. Name the process being tested in this experiment (1mark)
    2. Account for the observation (3marks)
12.  
    1. Define the term allergy (1mark)
    2. Distinguish between allograft and isograft (2marks)
13. State two adaptations of the placenta to its function (2marks)
14. The diagram below shows chemical reactions I and II which are controlled by enzymes.
    
    1. Into which class of carbohydrates is X? (1mark)
    2. Name reaction I and enzyme A (2marks)
       Reaction I…………………………………………………………………………………...
       Enzyme A…………………………………………………………………………………...
15. The figure below illustrates aerobic respiration in a cell
    
    
    1. Name the raw material named X and products A and B (3marks)
    2. Identify process T (1mark)
16. Name a characteristic in man controlled by multiple alleles (1mark)
17. Some scientists argue that Lamarck’s theory is false and not valid. What is your scientific view on this? (3marks)
18. State two natural ways in which in which seed dormancy can be terminated (2marks)
19. Explain why the temperate bears have thick adipose tissues (2marks)
20. Study the diagram shown below of the anterior view of a lumbar vertebra of a mammal.
    
    
    1. Name the parts labelled: A, and B, (2 marks)
    2. State the adaptation of the part labelled D. (1 mark)
21. Distinguish between parthenocarpy and parthenogenesis (2marks)
22. State three symptoms of menopause (3marks)
23. The figure below shows feet of various birds. Study the diagram and answer the questions that follow.
    
    
    1. Name the type of evolution represented by the diagrams. (1 mark)
    2. Using Darwin’s theory of evolution, explain how the feet of bird E would have evolved. (3 marks)
24. Describe how contraction of the diaphragm muscles leads to inhalation (4marks)
25. Explain the effect of burning of fossil fuels on the health of humans (3marks)
26. State two distinguishing characteristics of members of the kingdom Monera (2marks)
27. State two structural differences between the xylem and the phloem (2marks)
28. Explain why seeds buried deep in the soil fail to germinate (2marks)
29. Explain how starch provides energy for living organisms (2marks)
30. The diagram below shows part of the inner ear
    
    
    1. Name the apparatus (1mark)
    2. State the function of the apparatus (1mark)
    3. Name the parts labeled 1 and 5 (2marks)
31.     
    1. state the role of the following hormones during lactation (2marks)
       1. Prolactin
       2. Oxytocin
    2. Other than the role mentioned above, give another role of oxytocin in the body of a female (1mark)

Marking Scheme

1. Virology
   • Bacteriology
2. The fruit protects and nourishes the seed and embryo;
   • It also brings about dispersal of seeds;
3. Orange tree/plant fruit fly small bird large bird;
   • N/B The producer must be an organism, not an organ.
4.    
   1.            
      • The genus name started with a small letter,
      • The specific name started with a capital letter
      • The names are not underlined separately.
   2. Adansonia digitata the name must be underlined separately.
5.      
   1. Light microscope uses light for illumination while electron microscope uses a beam of electrons;;
   2. Light microscope uses light from the sun/artificial bulb while electron microscope uses electrons from an electron gun;;
   3.      
      • The degree of detail needed
      • The nature of the specimen
      • Size of the specimen
6.  In parasitism, the organism must not necessarily killed before the parasite obtains nutrients from it while in predation, the prey must be killed;
   • In parasitism, there is an association between the parasite and the host unlike in predation.
7.   
   1.  It contains proteolytic enzyme; that breaks down long chains of proteins to soften the meat;
   2. Quinine;
8.  Ileum is the lower part of the small intestine while ilium is one the fused bones (forming innominate bone with ischium and pubis) of the pelvic girdle;
9. They are artificially preserved yet fossil formation must accidental/natural;
10. Digestion was impaired and blood sugar regulation remained normal; digestion was impaired because the pancreatic juice containing digestive enzymes released did not reach the duodenum; blood sugar hormones, insulin and glucagon were released directly into the bloodstream;
11.         
    1. osmosis;
    2.      
       • X- X is hypotonic and therefore lost water to the liquid in the beaker by osmosis, hence reduction in the size of the visking tubing;
       • Y- Remained the same, the liquid Y was of the same concentration with the liquid in the beaker, hence no net movement of water by osmosis;
       • Z- Z is hypertonic and therefore drew water from the liquid in the beaker by osmosis, hence increased in the size of the visking tubing;
12.    
    1. allergy is a hypersensitive reaction to an antigen by the body;
    2.      
       • Allograft- this is a graft obtained from persons that are not genetically identical;
         Isograft- this is a graft obtained from a genetically identical twin.
13.   
    • It is glandular and secretes hormone progesterone and traces of oestrogen;
    • It is semipermeable/has a sinus to selectively allow substances into and out of the foetal circulatory system;
    • It is highly vascularized to create a steep concentration gradient for faster transport of dissolved food substances into the foetal circulatory system;
    • It has a countercurrent flow system, to maintain a steep gradient for maximum exchange of materials;
14.            
    1. disaccharides
    2.       
       • Condensation
       • Enzyme Maltase
15.     
    1.     
       • X- oxygen gas
       • A- energy/adenosine triphosphate
       • B- Pyruvic acid
    2. Glycolysis
16. Inheritance of ABO blood groups;
17. My scientific view is that is partly valid and partly false; valid in the sense the environment influences the phenotypic expressions of the genes; false, because phenotypically acquired characteristics in the course of the lifetime of an organism cannot be inherited because they do not affect the gene make up of an organism;
18. Suitable warm temperature, moisture, thinning down/softening of the testa by microorganisms;
19. Thick adipose tissues store a lot of fat; which insulate the body against heat loss;
20.          
    1. A- Neural spine
       B- Metapophysis reject Metapophyses
    2.  It is long to increase the surface area for attachment of (abdominal) muscles;
21. Parthenocarpy is the development of fruits without fertilization while parthenogenesis is the spontaneous development of an embryo from unfertilized egg cell;
22.         
    • Night sweats,
    • Random hot flashes during the day
    • Changes in mood that shows depression, fatigue.
    • Vaginal dryness
    • Loss of minerals such as calcium
    • Osteoporosis/softening of bones
23.    
    1. Divergent evolution
    2. Bird E evolved such feet which are used to scratch the ground to obtain food materials like worms and other soil organisms; It evolved to that to ensure the bird is better adapted to its environment; and therefore with that feet it can compete favourably for the limited food resources and this increases its survival;
24.  Diaphragm flattens; volume of the thoracic cavity increases; pressure of the thoracic cavity reduces; lungs are inflated/ air rushes into the lungs;
25.             
    
    • The oxides of nitrogen are poisonous to humans affecting their respiratory systems when inhaled;
    • Nitrogen (IV) oxide is carcinogenic/causes cancer;
    • High concentration of Sulphur (IV) oxide causes bronchitis, pneumonia and heart failure;
    • They slow down ciliary activities in the respiratory tract;
26.       
    • Their cell walls are made of murein/ proteins and sugars;
    • They lack membrane bound organelles/ few organelles/ lack mitochondria
    • Are prokaryotic;
27.  
    1. Xylem has lignified walls while phloem lacks;
    2. Xylem is made of dead cells while phloem is made of living cells;
28. This is because of limited oxygen; required for respiration to provide energy required for germination;
29. Starch is first hydrolyzed to simple sugars; which are then oxidized to provide energy;
30.   
    1. vestibular apparatus/vestibule;
    2. Maintain body posture in relation to gravity;
    3. 1- cochlea
       5- Semi-circular canals
31.  
    1. stimulates milk production
    2. Stimulates milk let down/stimulates the contractions of lobule containing alveoli to release milk into the lactiferous ducts;
    3. It stimulates the contractions of the myometrium during giving birth/parturition;