Biology Questions and Answers - Form 2 Term 3 Opener Exams 2022

INSTRUCTIONS:

• Answer all the questions in the spaces provided.

1.  
   1. Name the three main branches of biology. (3mks)
   2. List two other branches of biology(sub-branches) and for each give a definition. (4mks)
2. Biological knowledge can be used to solve environmental problems and enables one to pursue various careers.
   1. list three environmental problems that can be solved using biological knowledge; (3mks)
   2. Which three careers require the knowledge of biology. (3mks)
3.  
   1. The scientific name of irish potato in Solanum Tuberosum. Identify two errors that have been made when writing the name. (2mks)
   2. Which taxonomic group does the name solanum refer to? (2mks)
4. Which organelles performs the following functions:
   1. Transports proteins within the cells (1mk)
   2. Contains lytic enzymes (1mk)
   3. Processing and transportation of glycoprotein (1mk)
   4. Regulate the passage of materials into and out of a cell. (1mk)
5. The diagram below represents a cell as seen under the electron microscope.
        
   1.  
      1. Based on the diagram state whether it represents an animal cell or a plant cell. (1mks)
      2. Give two reasons for your answer in 5(a)(i) above. (2mks)
   2. State the functions of the structure labeled P, Q and R. (3mks)
   3. State three properties of the structure labeled T. (3mks)
   4. Name the part of the cell that is used in maintaining support in plant cells. (1mk)
6.  
   1. State the function of the following parts of a light microscope.
      1. Mirror (1mk)
      2. Condenser (1mk)
      3. Eye piece (1mk)
   2. Which part of a microscope enable one to change from medium to high power objective lens. (1mk)
   3. Explain why it is not advisable to use the coarse adjustment knob when viewing objects with the high power objective lens. (2 mks)
7. Study the diagram below and answer the questions below:
   
   1. Which physiological process was being investigated? (1mk)
   2. State two observations made after 30 minute. (2mks)
   3. Give an explanation for the observation made in 7(b) above. (3mks)
   4. State two factors that affect the process you named in 7(a) above. (2mks)
8.  
   1. Photosynthesis take place in two stages. Name the two stages and state where in the chloroplast each takes place. (4mks)
   2. State the role of light in the process of photosynthesis. (1mk)
   3. Which cells in a leaf that contains chloroplasts. (3mks)
   4. List two raw materials necessary during photosynthesis. (2mks)
9.  
   1. Name two enzymes that digest proteins in the human alimentary canal. (2mks)
   2. Explain why the enzymes you have named in (a) above secreted in inactive form. (1mk)
10.  
    1. Name two features that increase the surface area of the small intestines. (2mks)
    2. During a practical investigation students were provided with the following: Food substance, 10% sodium hydroxide solution, 1% copper sulphate solution and iodine solution.
       1. Identify two food substances that the students were expected to test. (2mks)
11. The diagram below represents a transverse section through a plant organ.
         
    1.  
       1. From which plant organ was the section obtained? (2mks)
       2. Give two reasons for your answer in (a)(i) above (2mks)
    2. On the diagram identify and name the part that
       1. Transports water and mineral salts. (1mk)
       2. Trans - locates synthesized food materials. (1mk)
12. State two structural differences between arteries and veins. (2mks)
13. The diagram below shows a vertical section through a mammalian heart.
            
    1. Name the parts labeled A and D. (2mks)
    2. Use arrows to show the direction in which blood flows out of the heart. (2mks)
    3. Name the muscle that makes up the heart chambers. (1mk)
    4. Which part of the heart is referred to as the pacemaker. (1mk)
14.  
    1. Give two reasons why blood clotting is important. (2mks)
    2. The diagram below illustrates the blood clotting process. Use it to answer the questions that follow.
       
       Name
       1. The blood cell represented by A (1mk)
       2. Metal ion represented by B (1mk)
       3. End product represented by C (1mk)
15.  
    1. State three structures used for gaseous exchange in terrestrial plants. (2mks)
    2. How are guard cells structurally adapted for gaseous exchange. (4mks)
    3. Name three structures used for gaseous exchange in frogs. (3mks)
16.  
    1. Define respiration. (1mk)
    2. Name the site of aerobic respiration in a cell. (1mk)
    3. List two substances needed for respiration to take place. (2mks)
17.  
    1. How are the respiratory surfaces in mammals adapted to their functions (3mks)
    2. State the functions of the following parts of a gill. (3mks)
       1. Gill rakers
       2. Gill bar
       3. Gill filaments

MARKING SCHEME

1.  
   1. Botany, zoology, microbiology
   2.  
      1. Ecology – The study of living organisms in their surroundings
      2. Entomology – study of insects
      3. Parasitology – study of parasites
      4. Ernbryology – study of development of animals from egg to adults
      5. Physiology - study of body function
      6. Anatomy – study of internal structures of living organisms
      7. Cytology – study of cells
      8. Pathology – study of fishes
      9. Bacteriology – study of Bacteria
      10. Morphology – study of external structure of organisms
      11. Biochemistry – study of chemistry of materials
      12. Taxnoomy – study of classification – sorting out of organisms into groups
      13. Histology – study of tissues
      14. Virology – study of viruses
          (any two)
2.  
   1. Food shortage, pollution, drought, poor health, conservation of natural resource
   2. Medicine, dentistry, agriculture, public health, veterinary practice, horticulture, nursing etc
3.  
   1.  
      • The species name starts with a capital letter.
      • The names are not underlined separately or italicized.
   2. Genus
4.  
   1. rough endoplasmic reticulum
   2. Lysosomes
   3. Golgi apparatus
   4. Cell membrane
5.  
   1.  
      1. plant cell
      2.  
         • presence of a cell wall
         • Presence of a chloroplast
         • Is regular in shape
   2.  
      • P - chloroplast – site of photosynthesis
      • Q - smooth endoplasmic reticulum – manufacture and transport lipid
      • R - Mitochondrion – site of respiration
   3. T 
      • Cell membrane
      • Sensitive to change in temperature and pH
      • has electrical change positive and negative charges
      • it is semi-permeable
   4. Cell wall
6.  
   1.  
      1. Mirror – reflects and directs light to the specimen
      2. Condenser – concentrates and directs light to the specimen on the stage
      3. Eye piece – magnifies the image of the object
   2.  
      • It may crush and destroy the objective lens
      • it may damage the slide containing the specimen
7.  
   1. Diffusion
   2.  
      • The starch solution inside the visking change from white to blue-black colour
      • The iodine solution in the beaker across the visking tubing by diffusion where they caused the starch solution to change to blue black.
   3. Starch molecules are large sized and cannot pass through the small pores of the visking tubing. Therefore the iodine solution did not change.
   4.  
      1. Surface area:
      2. surface area to volume ratio
      3. temperature
      4. size of the molecules.
      5. Thickness of the wall, tissue or member
8.  
   1.  
      • Stage I – Light stage – occurs in the granum
      • Stage II - dark stage – occurs in the stroma.
   2.  
      • Light provides energy required for splitting water molecules into hydrogen atoms and oxygen gas, a process called photolysis
      • Light is used in synthesis of energy in the form of adenosine triphosphate(ATP)
   3.  
      • Spongy mesaphyll cells
      • palisade mesaphyll cell
      • guard cells
   4.  
      • carbon(IV) oxide
      • water
9.  
   1.  
      • pepsin
      • Trypsin
   2. so that they do not digest the cells that secrete them
10.  
    1.  
       • long and coiled in length
       • Presence of many villi and microvilli
    2.  
       • protein
       • starch
11.  
    1.  
       1. dicotyledonous sten
       2.  
          • lacks root hairs
          • Vascular bundles are arranged in a ring around a central pith
    2.  
       1. xylem
       2. phloem
12. 
    

    Arteries	Veins
    Have thick muscular walls	Have thin less muscular walls
    Have no valves(except at the base of pulmonary artery and aorta)	Have valves at regular intervals
    Have a narrow lumen	Have a wide lumen
    Have elastic walls	Have less elastic walls

    
    
13. 1. A - AORTA
       D – right atrium/auricle
    2.  
    3. Cardiac muscle
    4. Sino atrial Node(SAN)
14.  
    1.  
       • to prevent excessive loss of blood when injured
       • The clot prevents entry of pathogen into the injured tissues
    2.  
       1. Platelets
       2. Calcium ions
       3. Fibrin/clot
15.  
    1.  
       • Stomata in the leaves
       • Lenticels on the woody stems
       • Epidermal cells on the roots/cubicle
    2.  
       • guard cells has thicker inner wall and thin outer wall to allow for differential expansion
       • contains chloroplasts unlike other adjacent epidermal cells for photosynthesis when glucose formed alters the osmotic pressure of guard cells.
       • they are bean shaped and face one another to form an aperture/pore.
    3.  
       • skin
       • buccal cavity
       • lungs
16.  
    1. it is the process by which food substances are broken down in the cell to release energy
    2. Mitochondrion\
    3.  
       • Food substance/glucose
       • Oxygen
17.  
    1.  
       • Highly vascuralised /rich network of capillaries to maintain a steep concentration gradient.
       • Moist to dissolve gases
       • Thin epithelial lining that is thin to provide a short distance for diffusing gases to cover.
       • Numerous to offer a large SA for maximum gaseous exchange.
    2.  
       1. Gill rakers - Trap/filters solid particles present in water/prevent solid particles from reaching the delicate gill filament so as to protect them from mechanical damage.
       2. Gill bar – Provide a surface for attachment of gill rakers and gill filaments
       3. Gill filaments- Provide a large surface area for gaseous exchange.