Biology Form Six Midterm Exam 2025 Mbulu Winners School

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PRESIDENT’S OFFICE
REGIONAL ADMINISTRATION AND LOCAL GOVERNMENTS
MBULU WINNERS SECONDARY SCHOOL
FORM SIX MID TERM EXAMINATIONS

INSTRUCTIONS

1. This paper consists of section A and B with a total of ten (10) questions.
2. Answer All questions in section A and only two (2) questions in section B.
3. Section A carries seventy (70) marks and section B carries thirty (30) marks.
4. Except for diagram that must be drawn in pencil, all writings should be in blue/black ink.
5. Cellular phones and unauthorized materials are not allowed in the examination room.
6. Write your Examination Number on every page of your answer booklet(s).

SECTION A (70 Marks)
Answer All questions in this section

1. (a) Draw a diagram to show the structure of a cell membrane and label the following parts using
   letters

A. Phospholipids with hydrophilic (heads) and hydrophobic (tails)
B. Phospholipid bilayer
C. Proteins shown in the bilayer
D. Glycoproteins
E. Cholesterol
F. Glycolipids shown
G. Thickness shown as 10 nm/ + or – 2 nm

(b) How does a non-photosynthetic prokaryotic cell differ in structure from eukaryotic plant cell?

2. (a) Mr. Sospeter carried out an experiment to test for protein in the given solution using Biuret test. In
   his experiment the results showed that the colour of the solution turned into purple or violent.
   (i)
   Identify the suitable reagent for the test
   (ii)
   Outline the procedure he followed during his experiment (b) What is
   the basis for positive results?

3. (a) Describe the significance of taxonomic hierarchy in classification:
   (b) Suppose you have been provided with the following specimens; frogs, lizards, guinea pigs, birds
   and bony fishes. Construct a bracketed/numbered key by using their respective classes to identify
   the specimen provided based on the following features; fur, feathers, type of fertilization and gills

4. (a) Why the Respiratory Quotient (RQ) for human beings lies between 07 and 1.0?
   (b) Explain how plants can live without specialized respiratory organs?

5. (a) Describe how polyspermy is prevented in mammals?
   (b) The chromosome number in radicle of a certain species of a flowering plant is 16. Giving reasons,
   calculate the number of chromosomes in each of the following cells:

(i) Pollen tube nucleus
(ii) Antipodal cells
(iii) Endosperm
(iv) Pollen mother cells
(v) Integuments

6. (a) Difference between each of the following terms
   (i) Exocytosis and endocytosis
   (ii) Pinocytosis and phagocytosis
   (b) Describe the mechanism of opening and closing of the stomata using illustrated starch-sugar
   interconversion hypothesis.

7. (a) How does nervous coordination differ from the hormonal coordination?
   (b) In Tanzania, agriculture is one of the important sectors in the development of the national economy
   in which about 80% of population are involved in crop production. Explain how synthetic plant
   hormones can be effectively used for large scale production in agriculture

SECTION B (30 Marks)
Answer any two (2) questions in this section

8. (a) Explain the meaning of electron transport chain and state the role played by oxygen in aerobic
   respiration
   (b) In aerobic cellular respiration the pyruvate undergoes a series of reactions in the citric acid cycle to
   yield energy. Briefly explain major products of citric acid cycle (c) Describe the importance of
   fermentation to human life

9. (a) Giving two reasons, explain how photosynthesis is important to the life of living organisms on earth
   (b) Describe how plants obtain light energy and convert it to biochemical molecules such as NADPH

• H+ and ATP

10. (a) Define each of the following.
    (i) Spermiation
    (ii) Spermiogenesis
    (b) Describe the events that take place during menstrual cycle