Biology Paper 1 Questions And Answers - Form 3 Term 2 Opener Exams 2021

Share via Whatsapp

BIOLOGY
PAPER 1
TERM 2 OPENER EXAM

INSTRUCTIONS

  • Answer all the questions in this paper

 

  1. State two ways in which the rough endoplasmic reticulum is adapted to its function.(2mks)
  2. State three characteristics that are used to divide phylum arthropoda into classes.(3mks)
  3. Distinguish between diffusion and active transport.(2mks)
  4. An organism was found to have the dental formula:
    I 1, C , PM , M 
      1      0          2       4
    1. Calculate the total number of teeth in the organism.(1mk)
    2. Giving a reason suggest the mode of feeding of the organism.(2mks)
  5.    
    1. Give a reason for the biconcave shape of the red blood cells.(Imk
    2. Name the enzyme that speeds up loading of carbon (iv) oxide in the red blood cells.(1mk)
  6.      
    1. Name the vitamin, an enzyme and a mineral element that are involved in blood clotting.(1½mks)
      1. Vitamin
      2. Enzyme;
      3. Mineral element
    2. Differenciate between heparin and histamine (2mks)
  7.      
    1. Name the part of the brain that influences breathing rate.(Imk)
    2. State two advantages of breathing through the nostrils instead of through the mouth in mammals.(2mks).
  8. The diagram below resents a cell organelle.
    biofeot221p1q8
    1. Name the main product of the organelle's activity (1½mk)
    2. Name the parts labeled A,B, C and D. (2mks)
  9.           
    1. State the cause of diabetes mellitus.(1mk)
    2. How may the disease in (9)(a) above be tested in a School laboratory?(2mks)
  10.          
    1. Distinguish between ecological niche and habitat (2mks)
    2. State two reasons why plants are included in a fish pond other than provision of food (2mks)
  11. State the functions of the following parts of a light microscope.
    1. Diaphragm (1mk)
    2. Objective lenses.(1mk)
  12.          
    1. Define the term respiratory quotient.(1mk)
    2.           
      1. After respiration of a certain substrate 50cm of carbon (iv) oxide was produced and 70cm Oxygen was used.Calculate the respiratory quotient of the substrate.(1 mk)
      2. Name the substrate in (12) (c) above. (1mk)
  13.              
    1. If a person who lives at low attitude moves to a higher attitude, changes occurring his blood consumption. Name two of these changes.(2mks)
    2. State the importance of these changes.(Imk)
  14. How are leaves of submerged plants adapted for photosynthesis? (2mks)
  15. Name the causative agents of the diseases below:
    1. Anthrax (Imk)
    2. Gonorrhea (Imk)
    3. Whooping cough(1mk)
  16. Explain why plants in waterlogged soils dry up.(3mks)
  17.           
    1. Name the antigens that determine human blood groups(2mks)
    2. Explain why people who have blood group AB are called universal recipients.(2mks)
  18. Name three processes in the human body in which homeostasis is involved.(3mks)
  19.         
    1. How are root hairs adapted to their function?(2mks)
    2. Name the process by which food is transported in plants.(Imk)
  20. State the significance of the following adaptations in a leaf.
    1. Thinness (Imk)
    2. Presence of airspaces(1 mk)
    3. Stomata (1mk)
  21. Study the food web below representing a certain ecosystem and use it to answer the questions that follow.
    biofeot221p1q21
    1. State the trophic level occupied by the lion in the food web.(1 mk)
    2. Write down a food chain in which the vulture is a tertiary consumer(1mk)
    3.      
      1. Name the organism with the largest biomass(1 mk)
    4. Give two reasons for your answer in (c)(i) above.(2mks)
  22. Explain how temperature affects an enzyme controlled reaction (3mks)
  23. The diagram below represents a certain plant.
    1. What is the likely habitat of the plant?(1mk)
      biofeot221p1q23
    2. Give two reasons for your answer in (a) above.(2mks)
  24. The number of stomata on the lower and upper surfaces of two leaves from plant species x and y were counted under the field of view of a light microscope. The results were as shown below.
    Leaf Number of stomata 
      Upper surface  Lower surface
     x  4  12
    y 20 23

    1. Which of the two leaves would be expected to have a lower rate of transpiration(1 mk)
    2. Give a reason for your answer in (a) above.Imk)
  25. Construct a dichotomous key for the animals listed below. Part of the key has already been constructed.Bird Snake, Lizard, Hyena.(4mks)
    1. Animal a mammal....... Hyena.
    2. Animal not a mammal... go to R.
  26. Other than transport of substances, state two other functions of mammalian blood.(2mks)
  27. Some students set-up the apparatus shown below to demonstrate the breeding mechanism in a mammal.
    biofeot221p1q27
    1. What structure in a mammal is represented by each of the following?
      1. The glass tube.(Imk)
      2. The ballons.(Imk)
      3. The bell jar.(Imk)
      4. String
    2. What happens when you pull the string downwards?
  28. The diagram shown below represents a part of the nephron. Use it to answer the questions that follow
    biofeot221p1q28
    1.          
      1. Name the parts labeled A,B,C and D.(2mks)
      2. Name the fluids found in C and D.(2mks) C
      3. Name the process by which the fluid found in D is formed(Imk)
      4. Mention one difference in the composition of the fluids in C and D.(Imk)
  29. Apart from having many features in common, state another characteristic of members of a Species (1mk)

MARKING SCHEME

  1.       
    • Presence of ribosomes for protein synthesis;
    • Presence of channels for transport of proteins and other substances; (1mk)
  2.     
    • Number of wings
    • number of legs and other appendages;
    • number of body parts;
    • type of eyes (simple or compound) max;1mk each
  3.       
    • Diffusion is movement of particles(ions ,molecules) from where they are more to where they are few against a diffusion gradient ;(1mk)
    • Active transport is the movement of ions/molecules from where they are few to where they are more using energy against a concentration gradient; (1mk)
  4.      
    • Upper jaw = 8x2=16
    • Lower jaw=7x2 =14/30;(1mk)
      Or (2+5+ 8) x 2 = 30 teeth.
    • Herbivorous ;(1mk)    
    • it has the molar, premolars and incisors except canines ;(1mk)
  5.     
    1. To increase the surface area over which gases will diffuse;Acc.oxygen or carbon (vi) oxide for gases.(1mk
    2. Carbonic anhydrase;
  6.     
    1.  
      • Vitamin K;
      • Thrombokinase /thromboplastin;
      • Calcium /calcium ions; (½mk)
    2.      
      • Heparin is a chemical substance that prevents blood form clotting within the blood vessels;(1mk
      • Histamine is a chemical substance that is produced by tissue cells after an injury/sting/allergic reaction ;(1mk)  
  7.       
    1. Modulla oblongata;(1mk)
    2.    
      • the nostrils have a mucus lining that traps dust unlike the mouth
      • Nostrils have cilia that facilitate the movement of dust particles outwards;
      • Nostrils have chemoreceptorۥs for detecting smells/chemicals unlike the mouth ;(max 2=2mks)
  8.       
    1. Energy/ATP;(1mk)
    2.      
      • A-Matrix;
      • B- Cristae;
      • C.Outer membrane
      • D-Inner membrane; (½mk @ max 2mks)
  9.     
    1. Little or no insulin in the blood;(1mk)
    2. Boil a little urine sample with Benedictۥs solution; an orange precipitate confirm presence of sugar in the urine;(2mks)
  10.         
    1. Ecological niche-the position an organism occupies and the role itpalys in a habitat;(1mk)
    2. Habitat – a specific place where an organism lives/adapted to live ;(1mk)
  11.    
    1. Diaphragm – regulates the amount of light passing through the specimen;(1mk)
    2. Objective lenses-for magnification of the specimen;(1mk)
  12.    
    1. Respiratory quotient-the ratio of the volume of carbon (iv)oxide produced to that of oxygen used in a respiratory process;(1mk)
    2.      
      1. R.Q =70cm3= 0.7;(1mk)
      2. Lipid;(1mk)
  13.       
    1. An increase in amount of haemoglobin,an increase in the number of red blood cells;(2mks)
    2. To increase the surface area for transport of oxygen/to increase the volume of oxygen in the body/to trap more oxygen;(1mk)
  14.                    
      • A greater number of chloroplasts that trap light of low intensity;
      • Their leaves are highly dissected /branched to increase the surface area for photosynthesis;
      • Epidermis has chloroplasts; (max 2=2mks)
  15.     
    • Bacillus anthracis;(1mk)
    • Neisseria gonorrheae;(1mk)
    • Bordetalla pertusis;(1mk)
  16. Due to anaerobic respiration; hence production of ethanol in the roots; which kills them and the whole plant;(3mks)
  17.     
    1. A and B ;(1mk each)
    2. They may be transfused with all other blood group’s they lack antibodies ‛aۥand‛ bۥ ;max (2mks)
  18.      
      • thermoregulation/regulation of body temperature;
      • Osmoregulation/regulation of water and salts.
      • Blood sugar regulation ;(3mks)
  19.        
    1.  
      • are elongated to increase the surface area of absorption;
      • their hypertonic sap enables osmosis to take place;
      • Presence of a thin cell membrane to quicken diffusion ;(max 2=2mks)
    2. Translocation ;(1mk)
  20.         
    1.     
      • to reduce diffusion distance of carbon (iv) oxide /reduce the penetration distance of light;
    2. for gaseous exchange /store gases;
    3. allows gaseous exchange /allows transpiration to take place;
  21.         
    1.      
      • Secondary consumer;(1mk)
    2.      
      1. Grass antelopes lions vulture;
      2. Grass caterpillars Guinea fowl Vulture;(1mk)
    3.     
      1. Grass;(1mk)
      2.  
        • Many organism’s depend on it for food/energy, being the primary producer;
        • energy is lost during its transfer to higher levels through respiration, excretion and defecation ;(2mks)
  22.     
    • Low temperatures inactivate enzymes;
    • increase in temperature up to the optimum increase the reaction rate/turn over;
    • higher temperatures above the optimum denatures enzymes;(3mks)
  23.           
    1. Desert/semi a desert; cc.arid/semi-arid areas;rej. Dry areas(1mk)
    2.      
      • Presence of large and succulent leaves;
      • pressure of thorns /prickles ;(2mks)
  24.       
    1. X; (1mk)
    2. Has fewer stomata on both sides of the leaf than Y;(1mk)
  25.          
      • 1a)Animal a mammal …………………………………hyena;
      • Animal not a mammal……………… go to 2;

      • Animal with body covered with feathers………………. Bird;
      • Animal with body not covered with feathers……………….. go to 3(1mk)

      • Animal with legs………………..lizard;(1mk)
      • Animal without legs……………………………………….snake ; (1mk)
        Acc.any other correct
        Key.
  26.     
    • Defense against infections;
    • Distribution of heat;
      (1mk each)
  27.         
    1.      
      1. Trachea; (1mk)
      2. Lungs (1mk)
      3. Rib cage;(1mk)
      4. Diaphragm;(1mk)
    2. Volume in the bell jar will increase ; and pressure will decrease in the bell jar;air will rush into the lungs filling them /inflating them;(3mks)
  28.      
    1.   
      1.          
        • A- Afferent arteriole;
        • B-Efferent arteriole;
        • C-Glomerulus ;
        • D-Bowman’s capsule;(½mk=2mks)
      2.     
        • C- Blood;(1mk)
        • D- Glomerulus filtrate ;(1mk)
      3. Ultrafiltration ;(1mk)
        • The fluid in C contains blood cells and large protein molecules while the fluid in D does not;(1mk)
  29. They interbreed to give rise to fertile offspring;(1mk)
  30.          
    1. The visking tubing is semi permeable; and allows the small glucose molecules into boiling tube by diffusion;(2mks)
    2.       
      1. the volume of the liquid in the boiling tube decreased .(1mk)
      2. The volume of the liquid in the visking tubing increased ;( 1mk)
  31.       
      • are moist to dissolve gases;
      • have a dense network of blood capillaries to transport gases;
      • They have thin membranes/thin epithelium to reduce the diffusion distance;
      • They have a large surface area for transport of more gases;
        1mk each=3mks
  32.        
    1. Deamination;(1mk)
    2. Helps to regulate the amount of proteins /amino acids in the body;(1mk)
    3. Liver (1mk)
Join our whatsapp group for latest updates

Download Biology Paper 1 Questions And Answers - Form 3 Term 2 Opener Exams 2021.


Tap Here to Download for 50/-




Why download?

  • ✔ To read offline at any time.
  • ✔ To Print at your convenience
  • ✔ Share Easily with Friends / Students


Get on WhatsApp Download as PDF
.
Subscribe now

access all the content at an affordable rate
or
Buy any individual paper or notes as a pdf via MPESA
and get it sent to you via WhatsApp

 

What does our community say about us?

Join our community on:

  • easyelimu app
  • Telegram
  • facebook page
  • twitter page
  • Pinterest