Biology Paper 1 Questions and Answers - Nyeri Mocks 2021 Exams

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  1. Explain why growing grass die a few days when salt is sprinkled on it. (2 marks)
  2. The diagram below illustrates tissue fluid and cells surrounding a capillary.
          NM2021 Bio PP1 ET2 Q2
    1. Name fluid G. (1 mark)
    2. Give two ways in which fluid G is difficult from tissue fluid. (1 mark)
  3. To examine a certain physiological process in animal cells, red blood cells were placed in different concentrations and results recorded. Use the illustration below to answer the questions that follow.
            NM2021 Bio PP1 ET2 Q3
    1. Which physiological process was being investigated. (1 mark)
    2. Name the concentration of solution (2 marks)
    3. Name the process W. (1 mark)
    4. Draw a well labelled diagram of a plant cell would be expected if it was placed in the same concentrations of A. (3 marks)
  4. Give an example of a phylum where all members have
    1. Open circulatory system. (1 mark)
    2. Closed circulatory system. (1 mark)
  5. Name the organelle that performs the following in a cell. (2 marks)
      1. protein synthesis
      2. Transport cell secretions
    2. Name a cell organelle abundant in a white blood cell. (1 mark)
  6. State the characteristic of living organism shown in each of the following
    1. Spore formation in Rhizopus spp (1 mark)
    2. Contractile vacuole expelling ammonia in an amoeba. (1 mark)
    1. State one function of the body tube in a light microscope. (1 mark)
    2. Why is it not advisable to bring to focus the high power objective lens by use of the coarse adjustable knob. (1 mark)
    1. Name two types of cell division. (2 marks)
    2. How does a cell prepare its visit for division. (2 marks)
  9. The energy used by a hawk for flying is obtained indirectly from the sun. Explain.   (3 marks)
  10. Distinguish between population and community. (2 marks)
  11. How are Ascaris lumbricoides adapted to their parasitic way of life? (3 marks)
    1. Name the class in the phylum arthropoda with the largest number of individuals. (1 mark)
    2. Give two reasons for your answer in (a) above. (2 marks)
    1. Define the term species as used in biology. (1 mark)
    2. State the characteristic of a species. (1 mark)
    1. Explain the role of vascular bundle system in plant nutrition. (2 marks)
    2. What is the adaptive value of a thick cuticle on a leaf? (1 mark)
    1. Name the sites of gaseous exchange in amphibians (3 marks)
    2. Why should a respiratory surface be:
      1. Moist (1 mark)
      2. Thin (1 mark)
  16. Below is a diagram of a flower.
            NM2021 Bio PP1 ET2 Q16
    1. Name the parts labelled A, B and C (3 marks)
    2. Suggest the agent of pollination for the flower. (1 mark)
    3. Give one reason for your answer in (b) above. (1 mark)
  17. State the economic importance of the following excretory products in plants.(2)
    1. Tannins
    2. Papain
  18. State two reasons why plants do not have complex excretory organs. (2 marks)
  19. State two conditions necessary for photosynthesis. (2 marks)
  20. Write a word equation representing the process of photosynthesis. (2 marks)
  21. Name two cells in a leaf that contain chlorophyll. (2 marks)
    1. The diagram below represents a section of a leaf.
      NM 2021 Bio PP1 Q22
      Name the parts labelled X and Y. (2 marks)
    2. Using arrows, indicate on the diagram the direction of flow of water during transpiration stream. (1 mark)
    3. Apart from the structures represented in the diagram above, name two other gaseous exchange structures in higher plants. (3 marks)
  23. The diagram below represents a section of the mammalian kidney.
          NM2021 Bio PP1 ET2 Q23
    1. Name structures E and F (2 marks)
    2. Explain why a camel has a longer nephron than a whale (2 marks)
  24. Give two ways in which the human intestinal villus is adapted to its function. (4 marks)
    1. State two functions of bile juice in the digestion of food. (2 marks)
    2. Explain why the action of salivary amylase stops at the stomach. (2 marks)
  26. What name is given to a group of hormones that controls the development of secondary sexual characteristics on a human male? (1 mark)
  27. What is the significance of meiosis? (2 marks)


  1. Steep concentration gradient created between salt and plant cell. Salt exerts osmotic pressure on cells of grass. Causes water to be drawn out via osmosis of the plant cell, cell looses turgidity, shrink and become flaccid/plasmolysed. Further water loss dehydrates cells, hence kills the plant.
    1. Plasma, blood plasma
      • Contains blood protein, blood cells (RBC)
      • High hydrostatic pressure
    1. Osmosis
      1. A – hypertonic solution
      2. Y – hypotonic solution/dilute solution
    3. crenation
      NM2021 Bio PP1 ET2 Ans3
    1. Arthropoda
    2. Chordata
      1. Ribosomes
      2. Endoplasmic reticulum
    2. Lysosome/golgi bodies
    1. Reproduction
    2. Excretion
      • Holds objectives lens in place
      • Holds eyepiece lens
      • HPOJ can break the glass slide on stage
      • Break lens of objective lens
      • Mitosis
      • Meiosis
      • Storage of enough energy in form of ATP
      • Duplication of DNA
      • Synthesis of more cell organelles
  9. Green plants through photosynthesis convert sunlight energy into chemical energy in food. Herbivores like mice, hare obtain some of this energy when they feed on plants. Hawks feed on small herbivores such as mice. Part of the food that hawks eat is used in respiration releasing energy for flight.
  10. Population – is the total number of all members of a species occupying a given area at a particular time while a community is a collection of populations of plants and animals occurring together in a given area at a particular time.
    • Have muscular pharynx which they use to suck semi-digested food from the intestinal lumen of their hosts.
    • Have thick elastic cuticle which is resistant to digestive enzymes of the host.
    • Eggs have a resistant shell that protects them from harsh environmental conditions.
    • Lay many eggs that remain ineffective for long periods of time ensuring successful transmission to next host.
    1. Insecta
      • They are able to fly.
      • They can inhabit many habitats
      • They have mouth parts for feeding
    1. Is the smallest unit of classification, whose members can freely interbreed to produce fertile offspring of the same kind.
    2. Members naturally interbreed to produce fertile offspring of the same kind.
      • Xylem – conduct water and mineral salt from the soil to leaves
      • Phloem – Translocates manufactured food from leaves to other regions of the plant.
    2. To reduce rate of transpiration
      • Skin
      • Buccal cavity/mouth
      • Lungs
      1. To dissolve the respiratory gases
      2. To reduce diffusion distance for faster diffusion of gases
      • A – sepal Rej sepals
      • B- Ovules Rej. Ovule
      • C- petal Rej. Plural
    2. Insect pollinated
      • The stigma is above the anthers
      • The stigma and anther are inside the flower/not hanging outside.
    1. Tannis – treatment of leather
    2. Papain – A meat tenderizer
    • Some of the waste products are re-used in the plant
    • Most of the waste products are from carbohydrates therefore less toxic
    • Chrorophyll
    • Sunlight
  20.                                             Chlorophyll
    Carbon (IV) Oxide + water arrowGlucose + oxygen Sunlight
    • Guard cells
    • Palisade cells
    • Spongy mesophyll cells
      • X – spongy mesophyl layer
      • Y – Cuticle

    2. Ans22b
    3. Lenticels; - pneumatophores
      • E- Glomerulus
      • F-Blood vessels
    2. A camel is a desert animal and has a long loop of Henle to increase the surface or water reabsorption to conserve water while the whale has a short loop of Henle to allow it loose more water. (OWTTE)
    • Has lacteals for absorption of food by active transport.
    • Is thin walled to reduce distance for diffusion
    • Has dense network of capillaries for efficient absorption and transport of nutrients.
    • Has micro villi for a large surface area.
      • Emulsification of fats to increase surface area for activity of enzyme lipase.
      • Mentradise acidity in the chime
      • Create an alkaline medium for enzyme activity.
    2. In the stomach, there is an acidic medium due to presence of dilute hydrochloric acid; which denatures the salivary amylase.
  26. Androgen
    • Responsible for gamete formation
    • Source of variation due to crossing over.

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