MITIHANI POPOTE EXAMINATIONS SERIES
FORM FOUR BIOLOGY EXAMINATION SERIES 6
INSTRUCTIONS
- This paper consists of sections A, B, and C with a total of eleven questions.
- Answer all questions in sections A and B and two questions from section C.
- Cellular phones and any unauthorized materials are not allowed in the examination room.
- Write your index number on every page of your answer sheets.
- All writings must be in blue or black ink except drawings which must be in pencil.
SECTION A (16 Marks)
Answer all questions in this section
1. For each of the items (i) – (x), choose the most correct answer among the given alternatives and write its letter beside the item number in your answer sheet provided.
- With regard to theories of evolution, which of the following does not show homology?
A. Beaks in birds
B. Foot structure in birds
C. Wing of birds and insect
D. Pentadactyl structure in vertebrate
E. Limbs structure in vertebrates
Answer: C
Explanation: Wings of birds and insects are analogous structures, not homologous, as they serve similar functions but have different evolutionary origins. - The following are the examples of farm animal waste:
A. Waste water, animal dung and carcases
B. Animal faeces, urine and carcases
C. Broken utensils, bottle and old books
D. Animal dung, carcases and old book
E. Rotten fruits, juice bottle and animal faeces
Answer: B
Explanation: Farm animal waste includes animal faeces, urine, and carcases, which are organic waste products from animals. - Which one of the following is true about the results from Mendel’s experiment?
A. Axial flower is dominant over terminal flower
B. Tallness is recessive to shortness
C. Inflated shape is recessive to constricted shape
D. Wrinkled seed is recessive to round seed
E. Yellow seed colour is dominant over shortness stem
Answer: D
Explanation: Mendel’s experiments showed that wrinkled seed shape is recessive to round seed shape in peas. - Which of the following part of the germinating seed is an embryonic shoot?
A. Radicle
B. Hypocotyl
C. Plumule
D. Epicotyl
E. Cotyledon
Answer: C
Explanation: The plumule is the embryonic shoot that develops into the stem and leaves during germination. - What is the suitable pH for working condition of pancreatic amylase?
A. Acidity
B. Basicity
C. Neutral
D. Both acidity and basicity
E. Neither acidity nor basicity
Answer: B
Explanation: Pancreatic amylase works optimally in a slightly basic (alkaline) environment, typically pH 7.5–8, in the duodenum. - Class Cestoidea consist of the organism except:
A. Taenia solium
B. Taenia saginata
C. Dipylidium caninum
D. Fasciola hepatica
E. Tape worm
Answer: D
Explanation: Fasciola hepatica is a trematode (Class Trematoda), not a cestode. All others are tapeworms (Class Cestoidea). - During menstrual cycle as the level of oestrogen start to rise:
A. Luteinizing hormone start to rise
B. Progesterone hormone inhibited
C. Follicle stimulating hormone is inhibited
D. Corpus luteum begin to form ovum
E. Testosterone production is stimulated
Answer: C
Explanation: Rising oestrogen levels inhibit follicle-stimulating hormone (FSH) via negative feedback during the menstrual cycle. - Ruth is pregnant, while attending maternal clinic the doctor told her that she can possibly give birth of a baby with defects. What supplements should Ruth be administered in order to give birth of a normal baby?
A. Ascorbic acid
B. Cobalamin
C. Riboflavin
D. Retinol
E. Folic acid
Answer: E
Explanation: Folic acid is essential during pregnancy to prevent neural tube defects in the baby. - Coordination is brought about through:
A. Digestive and respiratory system
B. Nervous and endocrine system
C. Circulatory and nervous system
D. Immune and reproductive system
E. Endocrine and digestive system
Answer: B
Explanation: The nervous and endocrine systems regulate coordination through nerve impulses and hormones, respectively. - The best distinction between diastolic and systolic blood pressure is that:
A. Diastolic blood pressure is common
B. Diastolic blood pressure is lower than systolic blood pressure
C. Diastolic blood pressure is the same as systolic blood pressure
D. Diastolic blood pressure is caused by contraction of ventricles while systolic blood pressure is caused by contraction of auricles
E. Diastolic pressure occurs in animal and systolic pressure occurs in both plants and animal
Answer: B
Explanation: Diastolic pressure (when the heart relaxes) is lower than systolic pressure (when the heart contracts).
2. Match the items in List A with the response in List B by writing the letter of the correct response in the space provided.
| List A | List B | Answer |
|---|---|---|
| Convert starch to maltose in the mouth. | A. Maltase B. Rennin C. Bile D. Peptidase E. Pepsin F. Sucrose G. Salivary amylase H. Pancreatic amylase I. Trypsin J. Pancreatic lipase |
G |
| Convert protein to peptide in the duodenum. | I | |
| Change lipid to fatty acid and glycerol. | J | |
| Change peptide to amino acids. | D | |
| Emulsifies fats and oils into tiny droplets. | C | |
| Composed by fructose and glucose. | F |
SECTION B (54 Marks)
Answer all questions in this section
3. (a) MR. GWAELI is a headmaster at Mwembe Chai High School; He is intended to construct a biology laboratory. What are the three features that should be considered by MR. GWAELI?
- Adequate space and ventilation: Ensure enough room for equipment and experiments with proper ventilation to handle chemical fumes.
- Safety features: Install fire extinguishers, first aid kits, and emergency exits to ensure safety during experiments.
- Proper lighting and utilities: Provide sufficient lighting and access to water, gas, and electricity for practical work.
(b) With a critical reason, deduce the following concepts.
- Transpiration is necessary evil.
Answer: Transpiration is essential for water and nutrient transport and leaf cooling but can cause excessive water loss, risking dehydration. - Arteries have thick walls than veins.
Answer: Arteries have thick, muscular walls to withstand high blood pressure from heart contractions, while veins have thinner walls due to lower pressure. - Uterine wall become thick few days before ovulation.
Answer: Rising oestrogen levels before ovulation cause the uterine wall (endometrium) to thicken, preparing for potential embryo implantation.
4. (a) Ms. HADIJA suffered from low blood sugar level. Which hormone would you recommend for regulating HADIJA'S blood sugar level? Give a reason to your answer.
Answer: Hormone: Glucagon. Reason: Glucagon, produced by the pancreas, raises blood sugar by stimulating glycogen breakdown and glucose release into the blood.
(b) Most of minerals especially Iron are essential and obtained from balanced diet taken daily:
- State why iron is vital in the body.
Answer: Iron is essential for haemoglobin production, which carries oxygen in red blood cells. - What will happen when a person lacks iron for a long period of time.
Answer: Prolonged iron deficiency leads to anaemia, reducing oxygen transport capacity. - What are four symptoms for a victim in 4 (b)(ii).
Answer:- Fatigue and weakness.
- Pale skin.
- Shortness of breath.
- Dizziness or lightheadedness.
5. (a) Mention four major precautions to be considered before performing a blood transfusion.
- Match donor and recipient blood types (ABO and Rh) to prevent reactions.
- Screen donor blood for infections (e.g., HIV, hepatitis).
- Ensure proper storage and handling of blood to avoid contamination.
- Verify patient identity and cross-match blood to confirm compatibility.
(b) Write alternative name of the following biological terms.
- White blood cell: Leucocyte
- Cell membrane: Plasma membrane
- Neuron: Nerve cell
- Platelets: Thrombocytes
- Red blood cell: Erythrocyte
6. Study the figure below then answer the following questions. [Note: Figure not provided, assuming cell B is a sperm cell, cell C is an egg cell, and cell A is a diploid cell undergoing division.]
- Observe and identify the type of reproduction in cell B and cell C.
Answer: Sexual reproduction (cell B: sperm, cell C: egg). - In two points state advantages of reproduction type mentioned in 6(a).
- Increases genetic diversity, enhancing adaptability.
- Allows combination of beneficial traits from two parents.
- Identify the type of cell division occurred in A.
Answer: Meiosis (produces gametes like sperm and egg). - Name the hormone responsible to produce cell B in human body.
Answer: Testosterone. - Give names of cell B and cell A.
Answer: Cell B: Sperm cell; Cell A: Spermatocyte (or diploid cell undergoing meiosis). - How a cell-B does is adapted to its roles? (Two points).
- Flagellum enables motility to reach the egg.
- Streamlined shape and minimal cytoplasm reduce resistance for efficient movement.
7. (a) Briefly explain the term organic evolution.
Answer: Organic evolution is the gradual change in the genetic makeup of populations over generations, leading to new species formation.
(b) With aid of at least one example, explain how does the following provide evidence about organic evolution:
- Homologous structure
Answer: Similar structures with different functions, like the pentadactyl limb in vertebrates (e.g., human arm and bat wing), indicate a common ancestor. - Analogous structure
Answer: Different structures with similar functions, like bird and insect wings, show convergent evolution due to similar environmental pressures. - Vestigial organs or structure
Answer: Reduced structures like the human appendix, once functional in ancestors, suggest evolutionary changes over time.
(c) Briefly explain two weaknesses and two strengths of Lamarck’s and Darwin’s theories of evolution respectively.
Lamarck’s Theory:
- Weaknesses:
- Inheritance of acquired traits (e.g., giraffe neck lengthening) lacks genetic evidence.
- No mechanism for trait transmission to offspring.
- Strengths:
- Recognized environmental influence on evolution.
- Proposed organisms adapt to changing conditions.
Darwin’s Theory:
- Weaknesses:
- Lacked knowledge of genetics to explain inheritance.
- Did not fully explain the origin of variations.
- Strengths:
- Natural selection explains survival of fittest traits.
- Supported by evidence like fossil records and adaptation.
8. Observe carefully your right-hand side and then if you have worn sweater remove it from your body. Then bend your right-hand side slowly while observing the changes taking place above the elbow when bending your arm.
- What are the changes taking place when bending your right-hand side?
Answer: The biceps muscle contracts and shortens, while the triceps muscle relaxes and lengthens, causing the arm to bend at the elbow. - Give the names of muscles involved during bending of your arm.
Answer: Biceps brachii (contracts) and triceps brachii (relaxes). - Briefly explain five functions of human skeleton.
- Support: Provides structural framework for the body.
- Movement: Bones act as levers for muscle attachment.
- Protection: Shields organs (e.g., skull protects brain).
- Blood cell production: Bone marrow produces red and white blood cells.
- Mineral storage: Stores calcium and phosphorus.
SECTION C (30 Marks)
Answer only two questions in this section
9. Cholera is among the threatening disease in the country. Give two points on how you will educate the people on its symptoms and four preventive measures to be taken to minimize the spread of the disease.
Symptoms:
- Severe watery diarrhoea leading to dehydration.
- Vomiting and muscle cramps.
Preventive Measures:
- Ensure access to clean, boiled, or treated drinking water.
- Promote proper sanitation and waste disposal.
- Encourage handwashing with soap before eating or handling food.
- Vaccinate populations in high-risk areas.
10. Mr. Musa was killing the earthworm when he was preparing his farm. You as a biologist use six points to convince that the earthworms are important to him.
- Earthworms aerate soil by burrowing, improving root growth.
- They enhance soil fertility by decomposing organic matter.
- Their castings enrich soil with nutrients like nitrogen.
- They improve soil drainage, preventing waterlogging.
- Earthworms increase microbial activity, aiding nutrient cycling.
- They help mix soil layers, promoting uniform nutrient distribution.
11. Explain any three effects of irresponsible sexual behavior and suggest three ways eradicating those behaviors in the community.
Effects:
- Spread of STIs: Unprotected sex increases risk of diseases like HIV/AIDS.
- Unplanned pregnancies: Leads to social and economic challenges.
- Emotional harm: Non-consensual acts cause psychological trauma.
Ways to Eradicate:
- Provide comprehensive sex education on safe practices.
- Ensure access to contraceptives like condoms.
- Promote community campaigns advocating responsible behavior.
No comments
Post a Comment