MITIHANI POPOTE EXAMINATIONS SERIES FORM FOUR BIOLOGY EXAMINATION SERIES 3 (With Marking Scheme)

MITIHANI POPOTE EXAMINATIONS SERIES

FORM FOUR BIOLOGY EXAMINATION SERIES 3

Time: 3 Hours

Instructions:

• Answer all questions in Sections A and B.
• Answer two (2) questions from Section C.
• Use neat diagrams where applicable.

SECTION A (16 Marks)

1. Multiple Choice Questions (10 Marks)

Choose the letter of the most correct answer and write its letter beside the item number:

1. During COVID-19 outbreak which is caused by corona virus, scientists in the world were struggling to find the solution. Under which branch of biology do the scientists were working?
   • a) Cytology
   • b) Virology
   • c) Taxonomy
   • d) Ecology
2. Mary was sick so she visited the doctor. The doctor ordered her body temperature, blood and urine sample for observation in the laboratory. Which scientific procedure was employed?
   • a) Data recording
   • b) Measurement
   • c) Hypothesis formulation
   • d) Experimentation
3. Some diseases are transmitted through sexual contacts, by means of vectors and contaminated foods and drinks. Which of the following is not a sexually transmitted disease?
   • a) Malaria
   • b) HIV/AIDS
   • c) Hepatitis B
   • d) Gonorrhea
4. Mr Majimoto asked form two students to collect a variety of fungi from their environments. Some fungi were found on dead tree logs, some on rotten food materials such as fruits and vegetables and others on soil. Why did they grow in those habitats?
   • a) The areas were moist and with soil
   • b) The areas had a lot of trees
   • c) The areas were moist warm and dark
   • d) The areas had enough sunlight
5. Look at your arm from the upper arm to the hand. What is the correct sequence of the bones you have?
   • a) Scapula, humerus, ulna, radius, carpals and phalanges
   • b) Humerus, radius, ulna, carpals, metacarpals and phalanges
   • c) Clavicle bone, humerus, ulna, radius, carpals, metacarpals and phalanges
   • d) Ulna, radius, biceps, triceps, scapula and phalanges
6. For growth to occur cells must divide mitotically in the body. What is the correct sequence of a cell which is dividing mitotically?
   • a) Prophase, metaphase, anaphase and telophase
   • b) Anaphase, metaphase, telophase and prophase
   • c) Pro-metaphase, metaphase, anaphase and telophase
   • d) Interphase, prophase, metaphase, anaphase and telophase
7. A feature that can be passed on from parents to offspring is:
   • a) Sex linked character
   • b) Phenotype
   • c) Genes
   • d) Sex influenced characters
8. In Mrere village there are a lot of fruits including mangoes, bananas, avocados and oranges but people in the village are complaining of hunger because it didn't rain and they didn't harvest maize and beans. What advice could you give them as a biologist?
   • a) To eat a lot of avocados
   • b) To eat a lot of oranges
   • c) To eat other alternative sources of food
   • d) To eat mangoes, avocados and oranges
9. Which of the following is not transported by blood plasma?
   • a) Faeces
   • b) Nutrients
   • c) Respiratory gases
   • d) Hormones
10. Angel planted castor seeds in order to harvest castor oil. As the seed started to germinate, the emerging shoot was observed. What was the name of the shoot observed?
    • a) Cytoplasm
    • b) Stems
    • c) Plumule
    • d) Radicle

2. Matching Items (6 Marks)

Match the letter of the correct response beside the item number in the answer sheet provided:

LIST A	LIST B
a. A type of seed germination whereby cotyledons are pushed above the ground	i. Micropyle
b. A pore which allows water to enter into seed during seed germination	ii. Meiosis
c. Inability of the seed to germinate	iii. Radicle
d. Prevent a viable seed to germinate	iv. Viability
e. A type of cell division whereby the same number of chromosomes is maintained from parent cell to daughter cell	v. Epigeal germination
f. Increases the length and height of roots and shoots	vi. Hard seed coat
	vii. Mitosis
	viii. Dormancy
	ix. Cotyledon
	x. Hypogeal germination
	xi. Lateral meristems
	xii. Apical meristems

SECTION B

3. Living and Non-Living Things (10 Marks)

1. Sort the organisms into living and non-living.
2. Give two reasons for placing the organisms above into living group.
3. Give two reasons for placing the organisms into non-living group.

4. Waste Management (9 Marks)

1. Explain three (3) ways which can be used to manage wastes at your school.
2. How do your school community benefits from proper waste management (03 points).

5. Aging Factors (9 Marks)

Predict six (06) possible factors might have caused the condition which Bwanaheri is experiencing.

6. Ecosystem and Food Web (10 Marks)

1. 1. Construct a food web from the list provided organisms above (Grass, Goat, Hen, Vulture, Grasshopper, Lizard, and Human being).
   2. From food web in which you construct which organisms are:
      • a) Producers
      • b) Primary consumers
      • c) Secondary consumers
2. Which important group of organisms should be included in the provided organisms to make the ecosystems balanced?

7. Excretion in Organisms (9 Marks)

1. Analyse the three (3) types of excretory products excreted by higher organisms.
2. Cite any three (3) organs used by higher organisms for excretion.

8. Genetic Cross in Peas (10 Marks)

1. Work out the genotypes for the F1.
2. Work out the following for the F2:
   1. Phenotypes
   2. Genotypes
   3. Phenotypic ratio
   4. Genotypic ratio
3. If the total number of all seeds were 7342. Find out the number of:
   1. Wrinkled seeds
   2. Smooth seeds

SECTION C

Answer any two questions from this section.

9. Body Defense Against Microorganisms (15 Marks)

Justify with five (05) points on how our bodies defend themselves against them.

10. Bacteria: Useful and Harmful (15 Marks)

Some bacteria are useful and others are harmful to man verify this statement by discussing three (3) points of their usefulness and three (3) points of their harmfulness.

11. Mechanism of Hearing (15 Marks)

Describe the mechanism which enabled James to hear the voice of a lion.

MITIHANI POPOTE EXAMINATIONS SERIES

FORM FOUR BIOLOGY EXAMINATION ANSWERS - SERIES 3

SECTION A ANSWERS

1. Multiple Choice Answers

1. b) virology
2. d) Experimentation
3. a) Malaria
4. c) The areas were moist warm and dark
5. b) Humerus, radius, ulna, carpals metacarpals and phalanges
6. d) Interphase, prophase, metaphase, anaphase and telophase
7. c) Genes
8. c) To eat other alternative sources of food
9. a) Feaces
10. c) Plumule

2. Matching Items Answers

List A	List B
a. A type of seed germination where cotyledons are pushed above the ground	v. Epigeal germination
b. A pore which allows water to enter into seed during germination	i. Micropyle
c. Inability of the seed to germinate	viii. Dormancy
d. Prevents a viable seed to germinate	vi. Hard seed coat
e. A type of cell division where the same number of chromosomes is maintained	vii. Mitosis
f. Increases the length and height of roots and shoots	xii. Apical meristems

SECTION B ANSWERS

3. Living and Non-living Things

i) Sorting:

Living: Baobab trees, mango trees, butterfly, dogs, birds

Non-living: Cars, stones, gravels, pebbles, water streams

ii) Reasons for living group:

1. They show characteristics of life (growth, reproduction, etc.)
2. They are made up of cells

iii) Reasons for non-living group:

1. They don't show characteristics of life
2. They are not made up of cells

4. Waste Management

i) Waste management methods:

1. Recycling paper, plastic and metal waste
2. Composting organic waste
3. Proper disposal in designated bins

ii) Benefits:

1. Reduces disease transmission
2. Creates cleaner learning environment
3. Can generate income from recycling

5. Factors for Premature Aging

1. Chronic stress
2. Poor nutrition
3. Excessive sun exposure
4. Smoking or alcohol abuse
5. Lack of sleep
6. Genetic predisposition

6. Food Web and Ecosystem

a) i) Food web:

Grass → Grasshopper → Lizard → Vulture

Grass → Goat → Human

Grass → Hen → Human

ii) Organisms:

a) Producer: Grass

b) Primary consumers: Grasshopper, Goat, Hen

c) Secondary consumers: Lizard, Human

b) Important missing group: Decomposers (bacteria, fungi)

7. Excretion in Higher Organisms

i) Excretory products:

1. Carbon dioxide (from respiration)
2. Urea/uric acid (protein metabolism)
3. Excess salts and water

ii) Excretory organs:

1. Kidneys (urine)
2. Lungs (CO₂)
3. Skin (sweat)

8. Genetics Problem

a) F1 genotype: Ss (all heterozygous smooth)

b) F2 results:

i) Phenotypes: Smooth and wrinkled

ii) Genotypes: SS, Ss, ss

iii) Phenotypic ratio: 3 smooth : 1 wrinkled

iv) Genotypic ratio: 1 SS : 2 Ss : 1 ss

c) Number of seeds:

i) Wrinkled seeds: 7342 × 1/4 = 1835.5 ≈ 1836

ii) Smooth seeds: 7342 × 3/4 = 5506.5 ≈ 5506

SECTION C ANSWERS

9. Body Defense Mechanisms

1. Skin barrier: Physical barrier preventing entry
2. Mucous membranes: Trap and remove pathogens
3. Inflammatory response: Increased blood flow brings white blood cells
4. Antibody production: Specific immune response
5. Phagocytosis: White blood cells engulf pathogens

10. Useful and Harmful Bacteria

Useful:

1. Digestion (gut microbiome)
2. Food production (yogurt, cheese)
3. Decomposition and nutrient cycling

Harmful:

1. Cause diseases (tuberculosis, cholera)
2. Food spoilage
3. Tooth decay

11. Hearing Mechanism

1. Sound waves enter ear canal
2. Eardrum vibrates
3. Ossicles amplify vibrations
4. Cochlea converts vibrations to nerve impulses
5. Auditory nerve sends signals to brain
6. Brain interprets as sound