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Form 3 Biology growth and development questions and answers

In this online learning session, we are going to solve Form 3 biology topical questions on growth and development.

Lessons (24)

• 1.    The diagram below shows an experimental set up to investigate an aspect of germination. (a) Why sodium hydroxide pellets used in this experiment? (b) Why is moist cotton wool used in this experiment? (c) (i) By means of an arrow, indicate on the diagram the direction in which red dye would move during the experiment. (ii) Give reasons for your answer in (c) (i) above.
  2m 32s

• 2.    The graph below represents the increase in the number of yeast cells over a period of 48 minutes. (a) Name the type of curve show (b) Determine the number of yeast cells after 26 minutes (c) Work out the rate of cell division between 24 and 28 minutes (d) After how long was the population of yeast cells 128? (e) Name the phase of the curve labelled (i) A to B (ii) B to C (f) Give reasons for the
  8m 32s

• 3.    A student set up an experiment as shown in the diagram below. The set up was at room temperature for a week. (a) What was the aim of the experiment? (b) What would be expected results at the end of the experiment
  1m 28s

• 4.    A culture of bacteria was incubated in nutrient agar at #35^0#C. Samples were taken at intervals in order to estimate the number of bacteria in the population. The data obtained is shown in the graph below. (a) When was the population of bacteria 350 million? (b) Account for the shape of the graph between (i) A and B (ii) B and C (iii) C and D (c) Give three reasons for the shape of the curve
  5m 56s

• 5.    An experiment was carried out to determine the growth rates of bamboo and a variety of maize plants in two adjacent plots. The average heights and average dry weight of plants from the two population were determined over a period of twenty weeks. The data is as shown in the table below. (a) Between which two weeks did the greatest increase in weight occur in (i) Bamboo (b) (i) Which of the two
  4m 59s

• 6.    A student set up an experiment as shown in the diagram below. (a) (i) What is being investigated in the experiment? (ii) On the diagram below indicate the expected results after three days. (iii) Why was it necessary to have wet cotton wool in the container? (b) What is the role of the following to a germinating seed (i) Oxygen (ii) Cotyledons
  2m 46s

• 7.    State two advantages of metamorphosis to the life of insects.
  0m 30s

• 8.    The diagram below represents a set up to investigate the conditions necessary for seed germination. The set up was left for seven days (a) What conditions were being investigated in the experiment? (b) State three reasons for soaking seeds in set ups A and B (c) What were the expected results after 7 days?
  3m 44s

• 9.    During germination and early growth, the day weight of the endosperm decreases while that of the embryo increases. Explain
  0m 38s

• 10.    State four applications of plant hormones in agriculture
  0m 42s

• 11.    Name three factors in seeds that causes dormancy
  0m 42s

• 12.    (a) Distinguish between epigeal and hypogeal germination. (b) Why is oxygen necessary in the germination of seeds?
  0m 56s

• 13.    (a) State two environmental conditions that can cause seed dormancy (b) Name the part of a bean that elongates to bring about epigeal germination.
  0m 51s

• 14.    Account for the following phases of a sigmoid curve of a growth of an organism (a) Lag phase (b) Plateau phase
  0m 45s

• 15.    (a) What is seed dormancy (b) Name a growth inhibitor in seeds
  0m 24s

• 16.    (a) The state during which a seed cannot germinate even when the conditions for germination are suitable is called (b) The diagram below represents a stage during germination of a seed (i) Name the type of germination illustrated in the diagram (ii) State the role of the part labelled x during germination of the seed.
  1m 22s

• 17.    In an experiment the shoot tip of a young tomato plant was decapitated as shown in the diagram below. (a) State the expected results after two weeks. (b) Give a reason for your answer in (a) above
  1m 16s

• 18.    State three factors that contribute to the decelaration phase in the population curve of an organism.
  0m 41s

• 19.    What is meant by the term apical dominance?
  0m 20s

• 20.    State four reasons why water is significant in seed germination.
  0m 45s

• 21.    State three aspects that can be used to estimate growth in seedlings.
  0m 26s

• 22.    State the role of the following hormones in the life cycle of insects. (a) Ecdysone hormone (b) Juvenile hormone
  0m 31s

• 23.    (a) State two differences between complete and incomplete metamorphosis (b) State the importance of moulting to an insect.
  1m 9s

• 24.    State the role of auxins in a plant stem
  0m 28s