Biology Questions and Answers - Form 2 Term 2 Opener Exams 2023

QUESTIONS ;

1. Define the term species. (2mks)
2. State the function of the following organelles. (3mks)
   1. Lysosomes
   2. Mitochondria
   3. Chloroplasts
3. Distinguish between diffusion and osmosis. (2mks)
4. Describe what happens during the light stage of photosynthesis. (3mks)
5. State two ways in which root hairs are adapted to their function. (2mks)
6. The diagram below represents a plant tissue.
   
   1. Identify the tissue. (2mks)
   2. Name the structures L and O and the cell labeled K. (3mks)
   3. State the function of structure labeled N. (1mk)
7. A setup that was used to investigate a certain process in plants is shown in the diagram below.
   
   1. What is this apparatus used for? (1mk)
   2. Giving reasons state two precautions that should be taken when setting up the experiment. (4mks)
8. The diagram below represents a transverse section through a plant organ
   
   1. From which plant organ was the section obtained. (1mk)
   2. Give two reasons for your answer in (a) above. (2mks)
   3. Name the parts labeled M, N and P. (3mks)
   4. State two functions of the parts labeled Q. (2mks)
9. State two functinal differences between arteries and veins in mammals. (2mks)
10.  
    1. A person of blood group O requires a transfusion. Name the blood group of the possible donors. (1mk)
    2. State the blood group(s) of people who can receive blood from people of all other groups and give the name given to such people. (2mks)
11.  
    1. Distinguish between a single circulatory system and a double circulatory system. (2mks)
    2. Name a class whose members have single circulatory system. (1mk)
    3. Name the openings to the chamber of the hearts of an insect. (1mk)
12. The diagram below shows a vertical section through a mammalian heart.
    
    1. Name the parts labeled A, B, C and D. (4mks)
    2. Use arrows to show the direction in which blood flows out of the heart. (2mks)
    3. Account for the difference in the thickness of the walls of the left and right ventricles. (3mks)
13. Explain four adaptive characteristics features of respiratory surfaces. (4mks)
14. Name three structures through which gaseous exchange takes place in terrestrial plants. (3mks)
15.  
    1. Name the structure for gaseous exchange in insects. (1mk)
    2. The diagram below illustrates the structure of a gill from a bony fish.
       
       1. Name the structures labeled A,B, and C and give their functions. (6mks)
       2. In what way are the structures labeled C adapted for their functions. (3mks)
16. Examine the diagram below and answer the questions that follow.
    
    1. Name the structures labelled A and B and the cell labeled H. (3mks)
    2. Give an adaptation of the cell labeled X. (1mk)

MARKING SCHEME

1. Define the term species. (2mks)
   • Are a group of organisms which can freely interbreed to produce a fertile offspring
2. State the function of the following organelles. (3mks)
   1. Lysosomes - Breakdown of worm out cell organelles or sometimes the whole cell when old and worn out
                          -Involves in intracellular digestion
   2. Mitochondria - Site of respiration/ ATP or energy production
   3. Chloroplasts- Site of photosynthesis.
3. Distinguish between diffusion and osmosis. (2mks)
   
   • Diffusion is the movement of molecules or ions from a region where they are at a high concentration to a region where they are at a lower concentration.
   • Osmosis is the movement of molecules from a region of low concentration thro a semi permiamble membrane
4. Describe what happens during the right stage of photosynthesis. (3mks)
   • Light energy is absorbed by chlorophyll and used in photolysis of water to split water molecules to form hydrogen ions and oxygen
   • Some of the trapped light energy is used to form ATP.
5. State two ways in which root hairs are adapted to their function. (2mks)
   • Numerous to increase the surface area for absorption of water and mineral salts.
   • Have many mitochondria to supply energy for active uptake of mineral salts.
   • Are thin walled to allow rapid movement of materials.
6. The diagram below represents a plant tissue.
   
   1. Identify the tissue. (2mks)
      • Phloem tissue
   2. Name the structures L and O and the cell labeled K. (3mks)
      • L - Sieve plate
      • O - Plasmodesmata
      • K-Companion cell.
   3. State the function of structure labeled N. (1mk)
      • Cytoplasmic filaments along which manufactured food streams.
7. A setup that was used to investigate a certain process in plants is shown in the diagram below.
   
   1. What is this apparatus used for? (1mk)
      • To determine the rate of transpiration.
   2. Giving reasons state two precautions that should be taken when setting up the experiment. (4mks)
      • Cut the shoot under water to avoid blockage of the xylem vessels by air
      • Apply petroleum Jelly between the cork/ rubber bung and the glass and between the rubber bung and the shoot to make the apparatus air tight.
      • Open the reservoir tap when assembling to remove the air bubbles from the tube.
      • Assembles under water to ensure no air bubbles are enclosed.
8. The diagram below represents a transverse section through a plant organ
   
   1. From which plant organ was the section obtained. (1mk)
      • Monocotyledonous root
   2. Give two reasons for your answer in (a) above. (2mks)
      • Has root hair
      • Xylem and phloem tissues are in groups arranged alternatively in a ring.
      • Has a pith
   3. Name the parts labeled M, N and P. (3mks)
      • M - Epidermis
      • N-Phloem
      • P - Eylem
   4. State two functions of the parts labeled Q. (2mks)
      • Absorption of water and mineral salts
      • Anchorage of plant
9. State two functions differences between arteries and veins in mammals. (2mks)
   • Arteries transport blood from the heart to the body tissues while veins transport from body tissues to the heart
   • Arteries transport oxygenated blood (other than PA) while veins transport deoxygenated blood other than PV
10.  
    1. A person of blood group requires a transfusion. Name the blood group of the possible donors. (1mk)
       • 0
    2. State the blood group(s) of people who can receive blood from people of all other groups and give the name given to such people. (2mks)
       • AB, Universal recipients
11.  
    1. Distinguish between a single circulatory system and a double circulatory system. (2mks)
       • In single circulation, blood flows through the heart once for a complete circuit while in double circulation blood flows through the heart twice for a complete circuit.
    2. Name a class whose members have single circulatory system. (1mk)
       • Fish / pisces
    3. Name the openings to the chamber of the hearts of an insect. (1mk)
       • ostia
12. The diagram below shows a vertical section through a mammalian heart.
    
    1. Name the parts labeled A, B, C and D. (4mks)
       • A -Aorta
       • B-Pulmonary vein
       • C - Bicuspid valve
       • D-Right auricle / Autrium
    2. Use arrows to show the direction in which blood flows out of the heart. (2mks)
    3. Account for the difference in the thickness of the walls of the left and right ventricles. (3mks)
       • The left ventricles has thicker walls than the right ventricles because it pumps blood a longer distance/ to all parts of the body hence requires to exert more pressure/force
13. Name three structures through which gaseous exchange takes place in terrestrial plants. (3mks)
    • Have thin epithelium for rapid diffusion of gases.
    • Have large surface area for rapid diffusion
    • Well vascularised to transport the diffusing gases
    • Have a moist surface to enhance diffusion.
14. Name three structure through which gaseous exchange takes place in terrestrial plant •
    •  Stomata
    •  Venticels
    • Pheumatophores
15.  
    1. Name the structure for gaseous exchange in insects. (1mk)
       • Tracheal system/ tracheoles
    2. The diagram below illustrates the structure of a gill from a bony fish.
       
       1. Name the structures labeled A,B, and C and give their functions. (6mks
          • A - Gill bar
            Function - Holds the gill filament and the gill rakes in position
          • B-Gill rakers
            Function -protects the delicate gill filaments from damage by solid particles
          • C-Gill filaments
            Function  - Are the sites for gaseous exchange
       2. In what way are the structures labeled C adapted for their functions. (3mks)
          • Highly folded and very many providing a LSA for gaseous exchange
          • Thin epithelical lining thus reducing distance over which gases have to diffuse.
          • Richly supplied with blood vessels/ highly vasculated.
16. Examine the diagram below and answer the questions that follow.
    
    1. Name the structures labelled A and B and the cell labeled H. (3mks)
       • A- Stoma
       • B-Sap vacuole
       • C - Epidermal
    2. Give an adaptation of the cell labeled X. (1mk)
       • Has chloroplast
       • Their inner wall is thicker and inerastic while the other wall is thinner and elastic.