Biology Questions and Answers - Form 1 End Term 3 Exams 2021

QUESTIONS

1. State the name given to the study of (2mks)
   1. Insects
   2. Classification of living organisms.
2.  
   1. Name the products of complete hydrolysis of sucrose. (1mk)
   2. What happens to these products named in (a) above, when they are excess in the body of man. (2mks)
3.  
   1. State the roles of light in plant nutrition. (2mks)
   2. Give a reason why glucose formed at the end of photosynthesis is converted at once into starch. (1mk)
4.  
   1. State the formula for calculating linear magnification of a specimen when using a hand lens. (1mk)
   2. Give one functional advantage of use of the following microscopes. (2mks)
      1. Light Microscope
      2. Electron Microscope.
5. An investigation was set up as shown in the diagram below.
                          
   After 30 minutes, starch suspension had turned blue-black while iodine solution retained its colour.
   1. Name the physiological process that was being investigated in the experiment. (1mk)
   2. Account for the results observed after 30 minutes. (3mks)
6. Define the term osmosis. (2mks)
7.  
   1. Distinguish between homodonts and heterodonts. (1mk)
   2. A certain mammal has no incisors, no canines, 6 premolars and 6 molars in the upper jaw.
      In the lower jaw, there are 6 incisors, 2 canines, 6 premolars and 6 molars.
      1. Write down the dental formular of this mammal. (1mk)
      2. What is the mode of nutrition of this mammal? ( 1mk)
8. The reaction represented by equation below occurs in the body
   Hydrogen peroxide → Oxygen + Water
   1. Name enzyme Z (1mk)
   2. Name an organ in the human body where this reaction occurs (1mk)
   3. State the biological importance of the reaction above (1mk)
9. State how each of the cells below are specialized to carry out their functions
   1. Palisade cell (1mk)
   2. A sperm cell (1mk)
10. State the functions of each of the following organelles.
    1. Ribosomes (1mk)
    2. Golgi apparatus (1mk)
11. Name the bond that exists between amino acids during condensation process of forming proteins? (1mk)
12. Explain how the following factors affect the rate of photosynthesis
    1. Concentration of carbon (iv) oxide. (1mk)
    2. Light intensity (1mk)
13. Study the figure below which shows a type of epithelial tissue
                         
    
    1. State the name of structure A. (1mk)
    2. Give an example in humans where this epithelium is found (1mk)
14. The diagram below represents part of the human digestive system.
                 
    Name the organs labeled L and M. (2mks)
    L: ………………………………………………………………………………………………
    M: ……………………………………………………………………………………………..
15. Some form one students wanted to collect the following animals for study in the Laboratory. State the suitable apparatus they should use.
    1. Flying insects ........................................................... (1mark)
    2. Crawling stinging insects .................................................... (1mark)
    3. Small animals from tree barks ................................................... (1mark)
16. Study the diagram below and answer the questions that follows
                           
    
    1. Identify the structures labeled A and B (2marks)
    2. What process takes place in the parts labeled A and B (2mark)
17. A student estimated the diameter of a field of view to be 2.8mm. The diameter was occupied by four onion cells. Estimate in micrometers the diameter of onion cell. Show your working. (2 marks)
18. The diagram below represents structure found in the walls of ileum.
                      
    
    1. Identify the structure shown in the diagram. (1 mark)
    2. Name parts labeled S, T and L. (3 marks)
       S .................................................................
       T .................................................................
       L .................................................................
    3. Name products of digestion which are absorbed into; (2 marks)
       L ..............................................................................
       T ...............................................................................
    4. State how the above structure is adapted to its function. (2 marks)
19. The diagram below represents a set up that was used to investigate a certain process in a plant.
                
    
    1. State the process that was being investigated. (1 mark)
    2. Other than the factors shown, state two factors that would affect the process named in (a) above. ( 2 mark)
20. Outline two roles of active transport in human beings. ( 2 marks)
21. Write the role of the following parts of microscope. (3marks)
    1. Mirror
    2. Diaphragm
    3. Coarse adjustment knob
22. Explain w hy plant cells do not burst when immersed in distilled water.(2mks)
23.  
    1. State two functions of bile juice in the digestion of food? (2marks)
    2. How does substances concentration affect the rate of enzyme reaction? (1mark)
24. The diagram below represents a cell
                        
    
    1. Name the parts labeled X and Y (2marks)
       X ...........................................................................................................................
       Y ..........................................................................................................................
    2. State why the structures labeled X would be more on one side than the other side.(1mark)
25.  
    1. What is diffusion (2marks)
    2. How does diffusion gradient affect the rate of diffusion? (1mark)

MARKING SCHEME

1.  
   1. Entomology;
   2. Taxonomy;
2.  
   1. Glucose and fructose;
   2. Oxidized (in the cells) to release energy;
      Converted (by the liver cells) into glycogen;
3.  
   1. Photosynthesis to provide hydrogen atoms required in the dark stage of photosynthesis;
      Synthesis of more/additional ATP required in the dark stage of photosynthesis;
   2. Starch is insoluble /osmotically inactive( hence does not affect the O.P of plant cells);
4.  
   1. Magnification  =   Length of drawing/image             rj Mg =
                             Corresponding length on specimen.
   2.  
      1. Studying /viewing live specimen;
      2. Higher power of resolution;
         Higher power of magnification;
5.  
   1. Diffusion; rj osmosis
   2. Visking is semi-permeable; allowing the smaller molecules of iodine to pass across ( to the starch suspension) while the larger starch molecules cannot across ( to the iodine solution);
6. Osmosis is the movement of water molecules from a region of high water concentration to a region of low water concentration across a semi pemeable membrane.
7.  
   1. Homodonts posses the same type/kind of teeth while heterodonts posses different types/ kinds of teeth;
   2. 1. I 0 ,  C 0,  pm  3, m 3 ;
           3       1         3       3
      2. Herbivorous; rj herbivore.
8.  
   1. Catalase;
   2. Liver;
   3. Breakdown of hydrogen peroxide into harmless products/water and Oxygen
9.  
   1. Has numerous chloroplast;
   2. Has long tail; acrosome; large nucleus. Full of DNA; a chromatin material/numerous mitochondria;
10.  
    1. sites for protein synthesis
    2. packaging and transportation of glycoproteins
11. Peptide bond
12.  
    1. Rate of photosynthesis increase as the CO₂ concentration increases up to optimum level (and vice versa)
    2. Rate of photosynthesis increases as light intensity increases up to optimum level; (and vice versa)
13.  
    1. A – ciliated epithelium
    2. Nasal / trachea epithelium.
14.  L-ileum
    M-pancrease
15.  
    1. Sweep net
    2. Pair of forcep
    3. Pooter
16.  
    1. A-Stroma
       B-Granular
    2. A Photosythesis (accept balanced equation)
       B Carbon iv oxide fixation (accept a balanced equation)
17. Diameter of cell = diameter of field of view ✓
                                   number of cells
                           = 2.8 ✓
                                4
                           = 0.7mm x 1000✓
                           = 700μm
18.  
    1. Villus
    2. S – Epithelium
       T – Lacteal
       L – Blood capillaries
    3. L – Amino acids, glucose
       T – Fatty acids and glycerol
    4. Supplied with blood capillaries – to transport absorbed products of digestion
       Presence of lacteals – To transport fatty acids and glycerol
       Lined with thin epithelium for faster absorption of products of digestion
19.  
    1. Photosynthesis;
    2. Carbon (IV) oxide concentration; (the valency power correctly)
       Temperature;
       Amount of chlorophyll; (b) is tied to (a)
       (Any two correct 1x2 =2mks)
20.  
    • (It facilitates the) reabsorption of useful substances in the kidney tubules into the blood stream;
    • (It facilitates the) absorption of digested food from the gut into the blood stream;
    • (It helps in the) movement of waste products from body into the blood stream/excretion of waste products from the body cells into the blood stream; (Any first two correct 2x1 = 2mks)
21.  
    1. Reflect light from the source for the microscope specimen;
    2. Regulate amount of light entering the microscope/reaching the specimen;
    3. Move body up and down in order to obtain a rough focus of image/specimen; (3mks)
22. Plant cells have cell wall; cell wall is rigid/cellulose cell wall is strong and rigid to withstand turgor pressure; Or water is absorbed by osmosis; cells become turgid; cell wall create inward pressure that prevent cell from bursting;
23.  
    1. Emulsification of fats, forms an alkaline medium for enzymes functions,
       Absorption of fats, iron, calcium
    2. Increasing substrate Concentration increases the rate of enzyme reaction.
24.  
    1. X-Chloroplasts;
       Y-Vacuole(s);
    2. Move to upper part of the cell in order to receive maximum light for photosynthesis ( in dimlight); (3mks)
25.  
    1. Movement of molecule/ions/atoms (acc substances) from a region of high concentration to a region of low concentration; (2mks)
    2. Diffusion gradient (2mk)
       The higher the diffusion gradient the faster the higher the rate of diffusion; (Acc the converse)