Biology Questions and Answers - Form 3 Term 1 Opener Exams 2021 ^Featured

• Answer all the questions in the spaces provided.

1. What are the main characteristics of kingdom protoctista. (3 mks)
2. Name the spore producing structures in (3 mks)
   1. Bryopyte –
   2. Pteridophyta –
   3. Fungi –
3. Study the figure below.
   
   1. Identify the organism. (1 mk)
   2. Give the name of the kingdom to which the organisms belongs. ( 1 mk)
   3. State two characteristics of the members of organisms in the kingdom you have mentioned in (b) above.    (2 mks)
4. Write four differences of plants in the class monocotyledonae and class dicotyledonae
   

   Monocotyledonae	Dicotyledonae

5. Name the main method of reproduction among bacteria. (1 mk)
6. Given the following organisms in a dam, construct a possible food chain for the dam.
   Small fish                                            Microscopic algae
   Crocodiles                                           Large fish
   Mosquito larvae.
7. Name two kidney diseases. (2 mks)
8. Why are plants able to accumulate most of the waste products for long? (1 mk)
9. Name three methods used by plants to excrete their waste productions. (3 mks)
10. State the conditions in human beings that results to the following:-
    1. Production of large quantities of dilute urine. (1 mk)
    2. Release of aldosterone hormone (1 mk)
    3. Release of glucagon hormone. (1 mk)
11. Name the class in the phylum arthropoda which has the largest number of individuals.    (1 mk)
12. State two characteristics of fungi. (2 mks)
13. Give a sample of urine, name one test you would carry out to determine if it was obtained from a person suffering from diabetes mellitus. (3 mks)
14. Give a classification of a housefly by filling the table below. (3 mks)
    

    Kingdom
    Phylum
    Class

15. State the changes that occur in arterioles in the human skin during thermoregulation.(2 mks)
16. Giving a reason in each case, name the class to which each of the following organisms belong.
    
    1. Bean plant –
       Reason –
    2. Bat –
       Reason –
17. State the use of Colchicine (1 mk)
18. Study the plant leaves than answers the questions that follow.
    
    1. Construct a possible dichotomous key to identify the leaf specimens. (3 mks)
    2. States the steps followed to identify the leaf specimens. (7 mks)
       

       Steps followed	Identity

Marking Scheme

1. What are the main characteristics of kingdom protoctista. (3 mks)
   • They are said to be eukaryotic since their nucleus is bound by a membrane
   • Most are mobile, and use flagella, cilia and pseudopodia.
   • Some are sessile.
   • They reproduce mainly asexually, by binary fission, fragmentation and sporulation.
   • Some reproduce sexually by conjugation.
   • Some are heterotrophic e.g. paramecium.
   • Others are autotrophic e.g. spirogyra.
2. Name the spore producing structures in (3 mks)
   1. Bryopyte – Capsule
   2. Pteridophyta – Sorus
   3. Fungi – Sporangium
3. Study the figure below.
   1. Identify the organism. (1 mk)
      • Euglena
   2. Give the name of the kingdom to which the organisms belongs. ( 1 mk)
      • Kingdom protoctista
   3. State two characteristics of the members of organisms in the kingdom you have mentioned in (b) above.   (2 mks)
      1. karyotic
      2. Reproduce asexually by binary fission
      3. Have many organelles enclosed by a membrane.
4. Write four differences of plants in the class monocotyledonae and class dicotyledonae
   

   Monocotyledonae	Dicotyledonae
   One cotyledon in the seed	Two cotyledons in the seed
   Fibrous root system	Tap root system
   Have parallel veined leaves	Have network veined leaves
   Vascular bundles scattered in the stem	Vascular bundles radially arranged in the stem

5. Name the main method of reproduction among bacteria. (1 mk)
   • Asexual through Binary fusion
6. Given the following organisms in a dam, construct a possible food chain for the dam.
   Small fish, Microscopic algae, Crocodiles, Large fish, Mosquito larvae.
   Microscopic algae  → mosquito larvae → small fish → large fish → crocodiles
7. Name two kidney diseases. (2 mks)
   1. Kidney stones
   2. Glomerular Nephritis
   3. Diabetes insipidus
8. Why are plants able to accumulate most of the waste products for long? (1 mk)
   • Most of the waste products are non toxic while some like oxygen are re-used within the plant.
9. Name three methods used by plants to excrete their waste productions. (3 mks)
   1. Guttation
   2. Exudation
   3. Deposition
10. State the conditions in human beings that results to the following:-
    1. Production of large quantities of dilute urine. (1 mk)
       • When pituitary gland is unable to produce antidiuretic hormone or produces it in inadequate amount, kidney tubules are unable to reabsorb water from the glomerulae filtrate.
    2. Release of aldosterone hormone (1 mk)
       • When there is higher concentration of sodium salts in the body.
    3. Release of glucagon hormone. (1 mk)
       • When the glucose concentration is lower than normal.
11. Name the class in the phylum arthropoda which has the largest number of individuals.   (1 mk)
    • Class insecta
12. State two characteristics of fungi. (2 mks)
    1. Basic unit is the hypha
    2. Cell wall contains chitin
    3. Eukaryotic
13. Give a sample of urine, name one test you would carry out to determine if it was obtained from a person suffering from diabetes mellitus. (3 mks)
    • To a portion of the solution, add an equal amount of Benedicts solution. Heat the mixture to boil. If the solution turns orange, it indicates presence of reducing sugars.
14. Give a classification of a housefly by filling the table below. (3 mks)
    

    Kingdom	Animalia
    Phylum	Arthropoda
    Class	Insecta

15. State the changes that occur in arterioles in the human skin during thermoregulation.(2 mks)
    • When its hot the arteries vasodilate
    • When its cold the arteries vasoconstrict
16. Giving a reason in each case, name the class to which each of the following organisms belong.
    1. Bean plant – Class dicotyledonae
       Reason – Two cotyledons in the seed
                     Tap root system
    2. Bat – Class mammalia
       Reason – Has mammary glands
                     Body covered with fur.
17. State the use of Colchicine (1 mk)
    • Treatment of gout.
18. Study the plant leaves than answers the questions that follow.
    1. Construct a possible dichotomous key to identify the leaf specimens. (3 mks)
       1.  
          1. Simple leaf …………………………………….. go to 2
          2. Compound leaf ………………………… go to 3
       2.  
          1. Leaf parallel veined ………………………….. go to 4
          2. Leaf network veined ………………………… go to 5
       3.  
          1. Three leaflets, leaf stalk ……………………. Bean
          2. More than three leaflets on leafstalk ………. Go to 6.
       4.  
          1. Leaf long and narrow ……………………… Napier grass
          2. Leaf broad and short ………………………. Trandescantia
       5.  
          1. Leaf with smooth margin …………………... mango
          2. Leaf with serrated margin …………………. Hibiscus
       6.  
          1. Pinnate leaf arrangement …………………. Mexican marigold.
          2. Bipinnate leaf arrangement …………………Jacaranda
             
             
    2. States the steps followed to identify the leaf specimens. (7 mks)
       

       Steps followed	Identity
       R 1b, 3b, 6a	Mexican marigold
       S 1a, 2a, 4a	Napier glass
       T 1b, 3a	Bean
       V 1b, 3b, 6b	Jacaranda
       W 1a, 2b, 5a	Mango
       X 1a. 2b, 5b	Hibiscus
       Y 1a, 2a, 4b	Trandescantia