Biology Paper 1 Questions and Answers - Form 3 End Term 1 Exams 2022

Answer all questions in the space provided.

1. Name the organelle that performs the following functions in a cell. (4marks)
   
   1. Transport of cell secretions
   2. Proteins synthesis.
   3. Formation of ATP.
   4. Fixation of carbon (IV) oxide.
2.    
   1. Distinguish between taxonomy and taxon (2marks)
   2. Arachnids and crustaceans belong to the same phylum. Name the phylum (1mark)
   3. State three characteristics that makes them to be classified in the phylum you stated in (b)above (3marks)
   4. Give one structural feature that can be used to differentiate crustaceans and arachnids (1mark)
3. In a certain experiment the field of view of the microscope was determined as 4 MM.If 16 cells were found to span across the diameter of the field of view of the microscope….
   
   1. Calculate the size of one cell in micrometers (3marks)
   2. If 100 epidermalcells were viewed under magnification * 150,how many cells will be observed at magnification * 450 using the same slide? (2marks)
4. Guard cells are specialized epidermal cells.
   
   1. State two structural features which suit them to their functions (2marks)
   2. Apart from gaseous exchange;give one other function of the stomata (1mark)
5. State three ways by which a baby may acquire immunity (3marks)
6. Distinguish between residual capacity and vital capacity (2marks)
7. Suggest the most suitable biological tool for collecting
   
   1. Ants from a tree trunk (1mark)
   2. Grasshoppers from grassland (1mark)
8.      
   1. State the functions of the condenser in a light microscope. (1mark)
   2. Why is it not likely to use an electron microscope in a school laboratory? (3marks)
9. Explain why plant cells do not burst when immersed in distilled water. (2marks)
10. An experiment shown below was a set up to investigate a certain physiological processes in plants.
    
    
    1. What process was been investigated? (1mark)
    2. What effect will the following have on the observation made in (a) above?
       
       1. Fanning the shoot (1mark)
       2. Removing all the leaves from the shoot (1mark)
       3. Placing the set up in the dark. (1mark)
11.      
    1. State the role of light in the process of photosynthesis (2marks)
    2. Name the product of the dark stage in photosynthesis (1mark)
    3. State two minerals elements that are necessary in synthesis of the chlorophyll (2marks)
12.        
    1. In an investigation, the pancreatic duct of a mammals was blocked, it was found that blood sugar regulation remains normal while food digestion was impaired. Explain these observations (3marks)
    2. State the functions of the bile juice in digestion (3marks)
    3. State the role of the tongue in mammalian digestion (2marks)
    4. The action of ptyalin stops at the mouth. Explain (2marks)
13. Give reasons for each of the following ;
    
    1. Constant body temperature maintained in mammals (2marks)
    2. Effects of low blood sugar in the body (2marks)
14. People can die when they inhale gases from burning charcoal in a poorly ventilated room. Explain (3marks)
15.      
    1. Name the compound found in the root nodule of the leguminous plants(1mark)
    2. State the association of the bacteria named in (a) above (1mark)
16. Name the features that increases the surface area of the mammalian small intestine (3marks)
17. The diagram below represents a transverse section of a plant organ
    
    
    1. From which plant organ was the section obtained ? (1mark)
    2. Give reason for your answers in (a) above (2marks)
    3. Name the part labelled J, K and L (3marks)
    4. State the functions of the part labelled M (4marks)
18. State two ways of preventing malaria (3marks)
19. Name the stage in meiosis where chromosome number is reduced by a half. (1mark)
20. Name;
    
    1. The protein secreted by the blood platelets necessary for blood clotting (1mark)
    2. The vitamin involved in blood clotting (1mark)
21. State two ways in which the tracheal system in an insect is adapted for gaseous exchange (2marks)
22. What are the importance of reproduction? (2marks)

MARKING SCHEME

1.        
   1. Golgi apparatus
   2. Ribosomes
   3. mitochondria
   4. chloroplast
2.        
   1. science of classification
      Unit of classification
   2. Arthropoda
      Have jointed appendages
      Have exoskeleton made up of chitin
      Segmented bodies
   3. crustacean have two pairs of antennae while arachnids have none
3.      
   1. diameter of the field of view =4mm and the number of the cells is 16
      Size of a cell = diameter of the field of view/number of cells
      4000/16 =250 micrometer
   2. 15000/450=33 cells
4.        
   1. Inner thick wall and outer thin wall which result into unequal expansion causing opening and closing of the stomata
      Presence of many chloroplasts
      Bean shaped
   2. It permit transpiration
5. Through breast feeding , immunization, genetical inheritance of nature immunity
6. Amount of air that remains in the lungs after maximum expiration
   Total amount of air that can be exhaled after taking the deepest possible breath
7.      
   1. pooter
   2. sweepnet
8.        
   1. To concentrate the light to the specimen on the stage
   2. It is expensive to acquire and maintain.
      Specimen preparation requires more time
      Requires expert to operate,
      Its very large and it requires specified room for operation
9. They have a tough and rigid cell wall that generate pressure equal and opposite to turgor pressure
10.      
    1. Transipiration
    2. Drop in water level, No change in water level; Very slow drop in water
11.        
    1. It acts as a energy that splits water into hydrogen and oxygen atoms. The hydrogen atoms formed is used in the dark stage
    2. Glucose/oxygen/amino acids
    3. magnesium and nitrogen
12.         
    1. Blokage of the pancreatic duct which prevent the juice from reaching the duodenum. Hormones are secrete directly to the blood and therefore the regulation of the sugar is not affected
    2. Emulsification of fats /maintain alkaline medium /neutralizes the acidity in the chyme from the stomach
    3. Turning the food in the mouth for proper mixing with saliva; roll food into bolus for swallowing
    4. Ptyalin works best in alkaline medium therefore its action stops in the due to acidic medium in the stomach
13.      
    1. To provide optimum body temperature for the enzyme activity
    2. low blood sugar reduces the respiratory activity of the cells and this reduces the production of energy and this can cause death. Low blood sugar can also affects the osmotic pressure of the body fluids
14. Due to production of carbon (II)oxide that forms carboxyhaemoglobin , that reduces the transportation of oxygen and it causes suffocation
15.      
    1. Rhizobium bacteria
    2. symbiosis
16. presence of villi and micro villi
    Being long
    Coiled
17.         
    1. root
    2. has root hairs,
       star shaped vascular bundle
    3. J peliferous layer, K phloem, L xylem
    4. absorption of water and the mineral salt
18. use of mosquito repellant on the skin
    Use of anti-malaria drugs
    Use of insecticides to kill mosquitos
    Drain stagnating water
    Sterilizing the male mosquitos
19. Anaphase I
20.          
    1. Thromboplastin
    2. vitamin K
21. The tracheoles are highly branched to increase the surface area ; they have thin membranes to allow gases to diffuse into the tissue ; They have moisted surfaces to dissolve the gases.
22. procreation; quality improvement