Biology Questions - Form 4 Mid-term Exams Term 1 2022

QUESTIONS

Attempt All Questions in the spaces provided.

1. Name the compound formed when carbon(II) oxide combines with haemoglobin. (1mk)
2. Give three ways in which herbaceous plants achieve support. (3 mks)
3. If glycerol is the same in all lipids, why is sunflower oil different from avocado oil? (1 mk)
4. Distinguish between transpiration and guttation. (2 mks)
5.                                        
   1. State the First Law of heredity. (1 mk)
   2. State any 3 causes of variation. (3 mks)
6. State two differences between DNA and RNA. (2 mks)
7.                
8. What is the role of
   1. Decomposers in an ecosystem? (2 mk)
   2. Producers in an ecosystem? (2 mk)
9. Red – green colour blindness is due to a sex – linked gene carried on the X – chromosome. A normal man marries a carrier woman for colour blindness.
   1. Using letter N for normal colour vision, make a mendelian cross to show the F1 genotypes and phenotypes. (4 mks)
   2. What are the chances that if they got a son as their first child, he will be colourblind?(1 mk)
   3. What is the phenotypic ratio of the F1 (1 mk)
   4. Define the term carrier as used in genetics. (1 mk)
10.                        
    1. Give the differences between the following structures in wind and insect pollinated flowers. (6 mk)
       

       	Insect	Wind
       i)  Anther
       ii)  Pollen grains
       iii) Stigma

    2. What is the importance of cross pollination? (1 mk)
    3. Explain how a seed is formed after an ovule is fertilized . (4 mks)
11.              
12.                          
13. An experiment was carried to investigate transpiration and absorption of water in sunflower plants in their natural environment with adequate supply of water. The amount of water was determined in two hour intervals. The results are shown in the table below.
    

    Time of day	Amount of water in grammes
    	Transpiration	Absorption
    1100 – 1300	33	20
    1300 – 1500	45	30
    1500 – 1700	52	42
    1700 – 1900	46	46
    1900  - 2100	25	32
    2100 – 2300	16	20
    2300 – 0100	08	15
    0100 – 0300	04	11

    1. Using the same axes, plot graphs to show transpiration and absorption of water in grammes against time of the day. (7 mks)
    2. At what time of the day was the amount of water the same for transpiration and absorption? (1 mk)
    3. Account for the shape of the graph of
       1. Transpiration. (3 mks)
       2. Absorption. (3 mks)
    4. What would happen to transpiration and absorption of water if he experiment was continued to 0500 hours. (2 mks)
    5. Name two factors that may affect transpiration and absorption at any given time. (2 mks)
    6. Explain how the factors you named in (e) above affect transpiration. (2 mks)