Biology Paper 2 Questions And Answers - Form 3 Term 2 Opener Exams 2021

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BIOLOGY
PAPER 2
TERM 2 OPENER EXAM

INSTRUCTIONS

  • This paper has 2 Sections: Section A and B 
  • Answer all questions in Section A
  • In Section B Question 6 is a compulsory section. 
  • Answer any one question between 7 or 8 in Section C

SECTION A (ANSWER ALL QUESTIONS)

  1.    
    1. The diagram below represents a plant cell.
      biofeot221p2q1i
      1. Name a carbohydrate which forms part of the structure labelled S. (1mk)
      2. State two functions of the part labelled R (2mks)
      3. Name two structures present in the diagram but absent in an animal cell (2mks)
    2. Name the organelles that perform each of the following functions (3mks)
      1. Excretion in amoeba
      2. Carries out digestion and destruction of worn out cell organelles
      3. Movement in paramecium
  2.           
    1. The diagram below represents a plant in the division Bryophyta.
      biofeot221p2q2a
      1. Name the parts labeled B and D (2mks)
        B -
        D -
      2. State one function for each of the parts labelled A and C (2mks)
        A -
        B -
    2.         
      1. To which phylum and class does the following organism belong ?
        biofeot221p2q2b
        Phylum -
        Class -
      2. Using observable features in the diagram, give two reasons for the phylum you have stated in (a) above
  3. The figure below shows a transverse section of a monocot stem. Study it and answer the questions that follow.
    biofeot221p2q3a
    1. Name the parts labeled A, B and C (3mks)
      A -
      B -
      C -
    2. State the function of the part labelled C (2mks)
    3. State three differences between a monocot stem and a dicot stem (3mks)
  4. The figure below illustrates a part of kidney nephron
    biofeot221p2q4a
    1. Name the parts labeled A, B and D (3mks)
      A -
      B -
      D -
    2. State one observable difference between part A and B
    3. Name the fluid that is found in part D (1mk)
  5. Below is a sketch diagram showing the parts of a mammalian circulatory system.
    biofeot221p2q5a
    1. Explain why the level of blood sugar in vessel 2 would be higher than that in vessel 3 during fasting (2mks)
    2. Name the vessel that has the highest concentration of urea among the vessels labelled 1,2 and 3 (1mk)
    3. How is vessel 3 structurally adapted to perform its functions. (3mks)
    4. Name the vessels labelled 2 and 4
      2 -
      4 -

SECTION B (40MKS)

  1. An experiment was set up to investigate the effect of light on the rate of photosynthesis in the shoot of a water plant. The gas given off by the shoot was collected for 5 minutes at different light intensities and the volume measured. The results obtained are shown on the table below.
    Ligth intensity(units) Gas collected(cm3/5min)
    1  0.35
    2 0.60
    3 0.85
    5 1.20
    10 1.55
    20  1.70
    30 1.80
    40 1.79
    50 1.79

    1. Using the data given in the table, plot a graph of the volume of the gas collected against light intensity. (6mks)
    2. Account for the rate of gas production in the following intervals of light intensity.
      1. 1 - 10 (2mks)
      2. 30 – 50
    3. Write a word equation for the process of photosynthesis (2mks)
    4. State the products of the light stage of photosynthesis
    5. State the role of light in photosynthesis.
    6. Other than light intensity, name two other factors that affect the rate of photosynthesis.
  2. Explain the economic importance of the organisms of each of the following kingdoms.
    1. Monera (10mks
    2. Fungi (10mks)
  3. Explain how abiotic factors (Environmental factors) affect plants. (20mks)

MARKING SCHEME

  1.    
    1.    
      1. Cellulose
      2.    
        • Store sugars, salt and food.
        • Carry out osmoregulation by inducing osmotic.
        • Gradient that brings about water movement.
        • Maintain the shape of the cell
      3.      
        • Cell wall
        • Chloroplast
    2.        
      1.     
        • Contractile vacuole
      2.      
        • Lysosomes
      3.      
        • Cilia
  2.         
    1.         
      1.      
        • B - Seta / Stalk
        • D - Rhizoid; Rej Rhizoids
      2.       
        • A - Production of spores / sporulation
        • C - Photosynthesis; OWTTE
    2.        
      1.        
        • Phylum - Arthropod
        • Class - Insecta
      2.       
        • Jointed appendages
        • Segmented body
  3.         
    1.         
      • A - Epidermis
      • B - Xylem
      • C - Cortex / parenchyma
    2.       
      • Stores water
      • Stores food substances
      • Support the stem
    3.        
      Monocot stem Dicot stem
      Vascular bundles scattered  Vascular bundles arranged in a ring 
      No pith  Presence of pith
      No vascular cambium Presence of vascular cambium
            
  4.         
    1.      
      • A - Afferent arteriole / vessel
      • B - Efferent arteriole / vessel
      • C - Bowman’s capsule
    2.      
      • Part A has wider lumen while part B has narrow lumen.
    3.       
      • Glomerular fitrate
    4.       
      • Proteins / plasma proteins
      • Blood cells
  5.           
    1.       
      • During fasting, no food is digested in the gut, thus vessel 3 has no sugar (glucose). Due to lack of food, glycogen (stored sugar) in the liver is broken down into glucose which is transported to the heart through vessel 2 for distribution into the body for respiration.
    2.       
      • Vessel 2
    3.        
      • Has large lumen to reduce pressure.
      • Has values to prevent blood from flowing backward.
      • Has thin inelastic muscles because it carries blood under low pressure.
    4.        
      • Vessel 2 - Hepatic vein
      • Vessel 4 - Aorta
  6.           
    1.    
      biofeot221p2Qa6    
        
    2.           
      1.      
        • The rate of gas production increases due to the increase in light intensity. The light provided energy for photosynthesis which released the gas.
      2.      
        • The rate of photosynthesis levels off / become constant. The optimum light intensity has been attained, so the gas production becomes constant due to other limiting factors.
    3.          
      •                                           Sunlight
        Carbon (iv) Oxide + water          →           glucose + oxygen
                                                Chlorophyll
    4.          
      • ATP, hydrogen atoms, oxygen.
    5.        
      • Light energy split the water molecules to oxygen and atoms / photolysis.
    6.         
      • Availability of water
      • Carbon (iv) oxide
      • Presence of chlorophyll
      • Temperature
  7.          
    1.        
      • Some bacteria causes disease in human beings such as vibrio used chlorine that causes cholera
      • Bacteria are used to treat sewage.
      • Bacteria cause dead plant and animals to decay this this realizing nutrients for us by plants.
      • Bacteria cause food spoilage.
      • Nitrogen fixing bacteria convert nitrogen to into nitrate which improves soil fertility.
      • They are used to process cheese and yoghurt.
      • Bacteria are used to produce organic acids alcohol, biogas and insulin.
      • Bacteria cause diseases in plants and livestock lowering production.
      • Used in bacteria and preserving tea and tobacco.
      • Preparation of silage. 5x2=10mks
    2.          
      • Some fungi such as penicillium are used to make antibiotics.
      • Some such as mushrooms are used as food.
      • Yeast is used in the brewing and bread baking industries.
      • Fungi cause decomposition of dead plants and animals releasing nutrients into the soil.
      • Some causes diseased such as ring worms and athlete’s foot in human beings.
      • Dry rot fungi destroy timber.
      • Some fungi such as bread mould cause food spoilage. 5x2= 10mks
  8.           
    1. Wind.    
      • Increases transportation.
      • Modifies the temperature which affects transpiration and photosynthesis.
      • Wind disperses fruits, seeds and spores.
      • Wind is an agent of pollination.
      • Strong winds’ break branches of trees and may uproot some trees
    2. Temperature.
      • Temperatures affect enzymatic reaction.
      • Influences the rate of photosynthesis and other biological reactions.
      • Increase in temperature increases the rate of transpiration.
    3. Light
      • Green plants need light for photosynthesis.
      • Some green plants need light for flowering or photoperiodism.
      • Some seeds require light for germinating.
      • Light effect opening and closing of stomata which affect transpiration, gaseous exchange and photosynthesis.
    4. Humidity
      • When humidity is low, the rate of transpiration increases due to less amount of water vapour in the atmosphere. When humidity is high, the atmosphere becomes saturated with water vapour, reducing the rate of transpiration.
    5. PH
      • Each plant requires a specific PH to grow well; acidic, alkaline or neutral.
    6. Salinity
      • Plants with salt – tolerant tissues, such as mangroves, grow in saline areas.
      • Plants in estuaries adjust to salt fluctuations
    7. Water / Rainfall
      • Water is necessary for germination.
      • Water is a raw material for photosynthesis.
      • Solvent and dissolves mineral salts for absorption and transport.
      • Transport medium for manufactured food.
      • Agent of fruit and seed dispersal.
      • Water is needed for turgidity of cells to give support to herbaceous plants.
    8. Atmospheric pressure
      • Variation in atmospheric pressure affects the amount of oxygen available for respiration and of carbon (IV) oxide for photosynthesis.
      • These two gases affect the distribution of organism.
      • Decreased atmospheric pressure increases the rate of transpiration
    9. Topography
      • The windward side of a hill receives enough rainfall and plants grow well.
      • The leeward side receives less rainfall and there is stunted plant growth.
      • Water drains readily from steep slopes which dry more quickly than flat.

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