Enlighten Knowledge; March 2024 Biology Mock Subjective Test and Answers. .
Enlighten Knowledge; March 2024 Biology Mock Subjective Test and Answers.
Q01
a. List four types of proteins found in the plasma membrane.
Expected response:
- Channel proteins,
- Transport proteins,
- Cell recognition proteins,
- Receptor proteins,
- Enzymatic proteins,
- Junction proteins.
b. Use the terms solute and solvent to describe a hypotonic and hypertonic solution.
Expected response:
- Hypotonic solution
A hypotonic solution has less solute and more solvent than the cell
- Hypertonic solution
A hypertonic solution has more solute and less solvent than the cell.
c. State three factors that can affect the speed of an enzymatic reaction.
Expected response:
- Optimum amount of substrate
- Optimum amount of enzyme.
- Optimum pH
- Optimum temperature.
- Co-enzyme
- Prosthetic groups/chemicals/inorganic ions.
- Nature of substrate.
e. Explain the process of osmoregulation in Amoeba.
Expected response:
- water from the surroundings flows into the cytoplasm by osmosis.
- Excess water collects in the contractile vacuole and enlarges it.
- The contractile vacuole moves to the surface of the cell where it bursts liberating the excess water.
- Thereby regulating the volume of the body fluid.
f. Explain why loam is a fertile soil.
Expected response:
- A fertile soil is one that supplies all the factors necessary for growth. Loam is a mixture of sand, clay, and humus.
- The proportion of sand and clay permits it type of soil to combine the necessary water-holding properties without reducing aeration and preventing waterlogging.
- The water in the soil acts as a solvent for mineral salts, the air provides oxygen and the humus or dead organisms act as a base of the detrital chain.
- The saprophytes (bacteria and fungi) break down the detritus into minerals which can be used by plants.
g. List five methods of conserving the soil.
Expected Answer:
- Avoid bush burning/fire
- Avoid overgrazing
- Application of manure or fertilizer to stabilize the soil
- Crop rotation
- Storm Drains; construction of barriers to stop free flow of surface water through the farm.
- Afforestation
- Mulching
- Terracing
- Strip cultivation
- Contour ploughing
h. What type of symbiotic relationship exists in mycorrhizae?
Expected Answer:
- Mutualism
Q02
a. What are the effects of adding;
α. animal manure to the soil?
Expected Answer:
- The manure provides nitrogenous materials which are converted to ammonium compounds.
- The manure improves the water-holding properties of the soil.
- It also binds soil particles together for proper growth and finally provides an indirect source of nitrate for plant growth.
- Manure produces and increases soil carbon which is an important source of energy that makes nutrients available for plants.
- Manure reduces runoff and leaching of nutrients in the soil.
β. lime to the soil?
Expected Answer:
- Lime is added to the soil to reduce or regulate the acidity.
- Adding lime to the soil causes the clay to clamp together (a process called Flocculation) into larger crumbs which have larger air spaces between them and therefore better drainage and aeration.
c. Explain briefly the effects of each of the following on the human body;
α. Excessive consumption of sugar
Expected Answer:
Excessive consumption of sugar;
- causes tooth decay
- lead to unnecessary weight gain
- cause obesity
- cause high blood pressure
β. lack of vegetables in the diet
Expected Answer:
Lack of vegetables in the diet;
- leads to constipation (due to the absence of roughage)
- cause a delay in the healing of wounds
- reduce resistance to disease
- leads to poor formation of bones
d. Name four forms of adaptive communication in animals.
Expected Answer:
- Sound / Auditory / Acoustic
- Visual
- Smell / Chemicals / Pheromones
- Tactile / Touch
- Electrical signal
- Display of colour
- Dancing
Q03
a. What is an endangered species?
Expected Answer:
- An endangered species is a species whose population has become so small that it may be lost or completely wiped out if not protected.
b. List four human activities that can cause a species to be endangered.
Expected Answer:
- Deforestation
- Illegal lumbering
- Illegal mining/quarrying
- Illegal hunting of wildlife (poaching).
- Bush fire/bush burning
- Fishing with chemical
- Pollution of water bodies
- Urbanization
c. What is a drug?
Expected Answer:
- A drug is any chemical substance other than food which changes the physiological state of the mind.
d. State four harmful effects of drug abuse on the health of the abuser.
Expected Answer:
- Risk of HIV infection or Hepatitis if drugs are injected with unsterilised or shared needles
- Causes convulsion/ mental imbalance or madness
- Weight loss or emaciation
- Causes psychosis or hallucination.
- Slow down reflex
- Depletion of finance
- Robbery
- Prostitution
- Loss of libido or sexual pleasure
- Possible addiction
- Premature death.
e. State four reasons why animals communicate with one another.
Expected Answer:
- For food
- Mating / Reproduction
- Territory defence
- Danger / Threat
- Tracking routes
f. How is conjugation different from sexual reproduction?
Expected Answer:
- In conjugation, the recipient prokaryotic cell acquires new DNA from the donor cell.
- Sexual reproduction occurs in eukaryotes and results in a new individual with a haploid set of chromosomes from each parent.
g. How do animals and fungi differ with respect to heterotrophy?
Expected Answer:
Animals are heterotrophs by ingestion, and fungi are heterotrophs by absorption
Q04
a. State five important parameters to consider in the biological drawing.
Expected Answer:
- Title
- Quality
- Size
- Magnification
- Clarity of lines
- Neatness of labels
- Details of drawing
- Guidelines must touch the parts and labels correctly spelt
- Avoid shading of drawing
- Drawing must be down wing pencil
b. Name the branch of science associated with the study of
Expected Answer:
| Study of; | Branch of biology |
| Plants | Botany |
| DNA | Genetics/Molecular Biology |
| Environment | Ecology |
| Animals | Zoology |
| Tissues | Histology |
c. Briefly describe the mechanisms involved in heat gain and heat loss in humans.
α. Mechanisms involved in heat gain
Expected Answer:
- Vasoconstriction
- Sweating
- Hairs become erect
- Increasing metabolic rate
- Behavioural change
(Correctly listed points and explained)
β. mechanisms involved in heat loss.
Expected Answer:
- Vasodilation
- Sweating
- Hairs lie flat or lowering of hairs
- Decreased metabolic rate
- Behavioural change
(Correctly listed points and explained)
Q05
a. What happens to pyruvate when oxygen is;
Φ. not available in a cell?
Expected Answer:
- Fermentation occurs when oxygen is not available (Anaerobic respiration takes place in the absence of oxygen)
γ. available in a cell?
Expected Answer:
- Pyruvate enters the mitochondria for further breakdown when oxygen is available. (Aerobic respiration occurs)
b. State two economic importance of each of the following insects;
α. cotton stainers
Expected Answer:
- They destroy cotton, silk cotton, kapok, cola, and baobab fruit
- The seeds of young cotton bolls are killed and the bolls drop when they are fed on.
- The saliva of the insect causes the seeds of the older bolls to stick together and the cotton lint is stained yellow and becomes useless.
- Fungi (Nematospora gossypii) are introduced during feeding and this kills the seed making the yield from the crop not realized.
β. termites
Expected Answer:
- Feed mainly on wood causing damage to timber, wooden houses, and electric poles
- They aerate the soil by burrowing activities
- They destroy certain agricultural crops
- They speed up the decay process thus increasing the humus content of the soil
- Some people feed on the wing reproductive.
- Removal of termitarium leads to an increase in the cost of ploughing or construction
- Soil from termitaria is used for tennis courts or cricket pitches
- It is given as feed for poultry.
c. List two control measures against each of the insects above.
α. cotton stainers
Expected Answer:
- Spray developing bolls with insecticides.
- Dust young bolls with a mixture of BHC and DDT to kill the bugs
- Small plantations are to be fenced with the introduction of chickens into the plantation to feed on the bugs.
- By trapping cotton stainer.
β. termites
Expected Answer:
- Wood to be used for building fence should be treated with termite repellents.
- Mix BHC (Benzene hexachloride) with the earth surrounding the building to keep termites away.
- Kill termites by using insecticides in the soil.
- The use of hardwood in buildings since these are not easily damaged by termites
- Concrete foundations for mud and wooden houses will prevent termites from getting easy access to the wood.
d. state three ways by which the following organisms are adapted to their habitats;
α. xerophytes
Expected Answer:
- They have deep-seated roots for tapping water from the soil.
- They possess succulent stems and leaves for water storage
- Modified leaves into spines or scale-like structures for reduction of water loss.
- Also, undergo seasonal shedding of leaves to reduce water loss.
- Presence of thick waxy cuticles or hairs on leaves to reduce water loss
- Rolling of leaves or sunken stomata to reduce water loss.
- Thick bark for fire resistance
- Reduce the number of stomata to prevent water loss.
β. hydrophytes
Expected Answer:
- They have large air space in leaves and stems for flotation or buoyancy.
- Stomata on the upper surface of floating leaves for gaseous exchange.
- Waxy upper cuticle for repelling water droplets
- Flowers are raised above water for the purpose of pollination
- Leaves with large surface area for maximum absorption of light
- Possession of soft or flexible stems of submerged plants which withstand the action of water currents.
- Submerged plants have thin cuticles permeable to water and mineral salts.
- Presence of pneumatophores for breathing or gaseous exchange.
- Small size of plants for buoyancy.
e. In typical grassland vegetation, state four possible effects of overgrazing by farm animals.
Expected Answer:
- Reduction of vegetation cover
- Destruction of soil structure
- Exposing soil to agents of erosion such as wind and water
- Compacting of soil prevents percolation of water into the soil
- Reduction in microbial flora and fauna
- reduction in activities of microorganisms
- Destruction of food chains
f. A pond at the back of a school dining hall containing living organisms was abandoned for some time.
α. List four abiotic factors likely to affect the organisms in the pond.
Expected Answer:
- Temperature and Carbon dioxide
- Density and oxygen
- Rainfall and Turbidity
- pH and Pressure
- Depth and Light intensity (2 marks)
β. State three;
BENEFITS
Expected Answer:
- For ecological research of organisms that live in the pond
- For collection of samples
- Balances water cycle in nature
- Habitat for some organisms
- Breeding ground or niche for some organisms
- For oxygen and carbon dioxide balance in nature.
- Balance food chain or food web
DISADVANTAGES
Expected Answer:
- Breeding spot for frogs and toads
- Breeding ground for mosquitoes, and water snails which could harbour Schistosoma and other vectors of diseases
- Could be a death trap
- Could cause air pollution and water pollution from decomposing organisms
- Health hazard for the environment and the school.
of the pond to the environment and school.
g. A young man fractured his leg in a motor accident. His leg was put in a cast and he was advised by the doctor to drink plenty of milk and spend some time in the sun. Briefly explain the reasons for the doctor’s instruction.
Expected Answer:
- Milk is a source of calcium /phosphorus needed for bone ossification/healing
- Milk is also a source of vitamins (A, B6, B12, C, D, E, and K) necessary for growth and repair
- Milk is also a source of lactose (milk sugar) for energy
- Sunlight is needed for the formation of vitamin D in the skin for the absorption of calcium for the hardening of the bones.
The objective test:
Enlighten Knowledge; March 2024 biology Mock paper 1
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