61 questions. Try each one, then open the answer to check yourself and read the explanation.
The diagram below illustrates the structure of Euglena. Use it to answer questions 1 to 3.
Which of the following structures is responsible for osmoregulation?
Answer: B (II)
II is the contractile vacuole near the reservoir, which pumps out excess water.
The diagram illustrates the structure of Euglena (parts labelled I to VI).
Excretion is carried out through the structure labelled
Answer: D (V)
Waste such as carbon dioxide and ammonia diffuses out through the body surface (pellicle/cell membrane), labelled V.
Below is a list of the levels of organisation in organisms. Use it to answer questions 4 and 5
I. Tissue II. System III. Cell IV. Organ
The correct sequence of the levels in an increasing order of complexity is
Answer: B (III, I, IV, II)
Cells form tissues, tissues form organs and organs form systems: III, I, IV, II.
Which of the following organelles is used for locomotion in Paramecium?
Answer: C (Cilium)
Paramecium swims by beating its many cilia.
Which of the following is not true of the nucleus of a living cell? It contains
Answer: E (ribosomes)
The nucleus contains nucleoplasm, chromosomes (made of chromatids) and a nucleolus; ribosomes are found in the cytoplasm.
The cell membrane consists of
Answer: C (lipids and proteins)
The cell membrane is made mainly of a double layer of lipids with proteins in it.
Which of the following is not likely to be found in the cell of a ripe tomato fruit?
Answer: B (Chlorophyll)
When tomato ripens its chlorophyll breaks down and red pigment takes over.
Osmosis can be defined as diffusion of
Answer: D (water molecules from a dilute solution to a concentrated solution through a semi-permeable membrane)
Osmosis is water moving from a dilute to a concentrated solution through a semi-permeable membrane.
In cellular respiration, energy is stored in the from of
Answer: C (adenosine triphosphate (ATP))
Energy released in respiration is stored in ATP, which the cell uses when it needs energy.
Which of the following processes is responsible for the increase in length and dry mass in a root tip?
Answer: C (Mitosis)
Cells at the root tip divide by mitosis, making more cells, so the root grows.
Which of the following explains the need for transport system in large mammals?
Answer: B (The area to volume ratio diminishes with large size)
Big animals have a small surface area compared with their volume, so diffusion alone is too slow; they need a transport system.
Oxygenated blood from the lungs is carried to the left auricle of the heart through the
Answer: A (pulmonary vein)
The pulmonary vein returns oxygenated blood from the lungs to the left auricle.
Which of the following is not correct about blood platelets? They
Answer: D (neutralize the toxins in the blood)
Platelets help blood to clot; neutralising toxins is done by antibodies (antitoxins).
The diagram illustrates an experimental set-up. Use it to answer questions 16 and 17
The part labelled I is
Answer: C (a water droplet)
Water vapour transpired by the plant condenses into droplets on the inside of the bell jar.
Use the diagram of the experimental set-up (a potted plant under a bell jar).
The function of the part labelled II is to
Answer: D (prevent evaporation from the soil)
Covering the soil stops water evaporating from it, so any water collected must come from the leaves.
Which of the following can be used to detect the loss of water vapour from the leaves of plants?
Answer: D (Blue cobalt chloride paper)
Dry cobalt chloride paper turns from blue to pink when it absorbs water.
The medium in which dissolved nutrients are transported in the body of vertebrates is called
Answer: D (blood)
Blood plasma carries dissolved food around the vertebrate body.
Which of the following organisms and organs of gaseous exchange are not appropriately matched?
Answer: C (Adult toad-gills)
Adult toads breathe with lungs, skin and mouth lining; only tadpoles have gills.
Which of the following structures of the leaf contains air?
Answer: C (Intercellular space)
Air fills the intercellular spaces of the spongy mesophyll, linked to the stomata.
Which of the following organs is specially adapted for gaseous exchange in aquatic organisms?
Answer: C (Gills)
Gills take dissolved oxygen from water.
Use the diagram below to answer questions 23 to 25
The part labelled I is the
Answer: B (grey matter)
I points to the dark H-shaped inner region of the spinal cord, the grey matter.
Use the diagram of the spinal cord and reflex arc (parts labelled I to V) to answer this question.
What is the function of the part labelled III?
Answer: E (Transmitting the impulses to the brain)
III is the sensory nerve fibre from the receptor; it carries impulses into the spinal cord, from where they are passed on to the brain.
Use the diagram of the spinal cord and reflex arc (parts labelled I to V) to answer this question.
Which of the following statements is correct of the structure labelled III? It
Answer: B (conducts impulses to the spinal cord)
The sensory neurone carries impulses from the receptor into the spinal cord.
What part of the brain is concerned with the regulation of the heart beat, body temperature and breathing rate?
Answer: B (Medulla)
The medulla oblongata controls automatic activities such as heartbeat and breathing.
The mammalian skin can insulate the body from cold because it has
Answer: C (the subcutaneous fatty layer)
Fat is a poor conductor of heat, so the fat layer under the skin keeps body heat in.
Which of the following parts of the tongue is sensitive to sugar
Answer: A (Tip)
Sweet tastes are detected mainly at the tip of the tongue.
The organ which is sensitive to smell in a cockroach is the
Answer: C (antenna)
Insects smell with receptors on their antennae.
Which of the following is the most sensitive spot of the retina?
Answer: D (Yellow spot)
The yellow spot (fovea) has the most cones and gives the sharpest vision.
The correct route through which the ovum passes from the ovary to the vagina is
Answer: B (ovary → fallopian funnel → uterus → cervix → vagina)
The ovum is caught by the funnel of the oviduct, passes down to the uterus, then through the cervix to the vagina.
Which of the following is the function of bright coloration of petals in flowers?
Answer: C (Attracting pollinating insects)
Bright petals attract insects, which carry pollen between flowers.
The series of activities preceding mating of the male and female animals is generally known as
Answer: C (courtship)
Courtship is the behaviour that leads up to mating.
Which of the following is not a feature of a seed or fruit dispersed by the wind?
Answer: E (Hooks)
Hooks catch on animals' fur, so they suit animal dispersal.
The following are necessary for photosynthesis to take place except
Answer: E (oxygen)
Oxygen is a product of photosynthesis, not a requirement.
Which of the following bacteria reduces nitrates in the soil to gaseous nitrogen?
Answer: D (Denitrifying bacteria)
Denitrifying bacteria turn nitrates back into nitrogen gas.
Which of the following is not an example of a heterotrophic mode of nutrition?
Answer: D (Holophytism)
Holophytic nutrition is photosynthesis, an autotrophic mode.
Predation is an example of a factor in an ecological system referred to as
Answer: E (biotic)
Predation is caused by a living organism, so it is a biotic factor.
Which of the following world biomes is found in Nigeria?
Answer: A (Sahel Savannah)
The Sahel savanna occurs in the far north of Nigeria.
A hygrometer is used for measuring
Answer: A (relative humidity)
A hygrometer measures the relative humidity of the air.
Which of the following is used for the collection of small insects from soil, leaf litter and crevices?
Answer: A (Pooter)
A pooter sucks small insects into a collecting tube.
A food web can be described as a
Answer: A (complex feeding relationship in a community)
A food web is many food chains linked together: a complex feeding relationship.
The pathway through which nutrient elements are replenished and circulated in an ecosystem is called a
Answer: A (cycle)
Nutrients go round and round in cycles (e.g. carbon, nitrogen cycles).
Which of the following statements is not correct?
Answer: E (Mushroom growing on decaying wood illustrates parasitism)
A mushroom feeding on dead, decaying wood is a saprophyte, not a parasite.
In which of the following are food grains best preserved?
Answer: A (Silos)
Silos keep grain dry and free of pests for long periods.
Which of the following is not a structural adaptation of desert plants for water conservation?
Answer: D (Broad leaves with numerous stomata)
Broad leaves with many stomata lose a lot of water, the opposite of what desert plants need.
Which of the following is a pollutant of air?
Answer: C (Carbon monoxide)
Carbon monoxide from engines and fires is a poisonous air pollutant.
Transmission of the malaria parasite is effected through the bite of the
Answer: E (infected female Anopheles mosquito)
Only a female Anopheles that already carries Plasmodium can pass malaria on when it bites.
The burning of farmlands should be discouraged because it
Answer: D (destroys the organic part of the soil)
Burning destroys humus and soil organisms, making the soil poorer.
Which of the following soil types retains the least amount of water?
Answer: B (Sand)
Sand has large particles and large pore spaces, so water drains through quickly.
Blood groups and tongue-rolling are examples of
Answer: B (discontinuous variation)
You either have a blood group or you don't, and can or cannot roll your tongue: clear-cut groups, so discontinuous variation.
Which of the following statements is not correct about sex-determination?
Answer: E (Females alone determines the sex of of child)
The father's sperm (X or Y) decides the sex; the mother always gives an X.
Which of the following is not a type of finger-print?
Answer: C (Simple)
The fingerprint patterns are arch, loop, whorl and compound (composite); 'simple' is not one of them.
Which of the following is the precise location of the gene?
Answer: A (Chromosome)
Genes are found at particular places along the chromosomes.
How many chromosomes are found in the human ovum?
Answer: B (23)
Gametes are haploid, so a human ovum has 23 chromosomes.
If a black guinea pig of genotype BB, is crossed with a white guinea pig of genotype bb, what will be the phenotype of the F1 generation?
Answer: B (All the offsprings would be black)
BB × bb gives only Bb, and black is dominant, so all are black.
How are Savannah plants protected from bush fires? They
Answer: C (have thick barks)
Thick, corky bark protects savanna trees from fire.
The failure of a species to adapt to any environment leads to
Answer: D (extinction)
A species that cannot adapt dies out: extinction.
The theory of use and disuse of organs was propounded by
Answer: C (Jean Lamarck)
Lamarck proposed the theory of use and disuse.
(a) List the principal sense organs in mammals and their functions
(b) (i) Describe the eye defect in which only distant objects are seen clearly (ii) How can it be corrected? Illustrate your answer with labelled diagrams
(c) Make a large labelled diagram of the vertical section through the mammalian skin
(a) Eye – sight; ear – hearing and balance; nose – smell; tongue – taste; skin – touch, pressure, pain, heat and cold
(b)(i) Long sight (hypermetropia): near objects are blurred; light from a near object is focused behind the retina because the eyeball is too short or the lens cannot become thick (convex) enough
(ii) Corrected with converging (convex) lenses, which bend the light so it focuses on the retina; diagrams: uncorrected eye with focus behind the retina, and corrected eye with convex lens and focus on the retina
(c) Labels: epidermis (cornified layer, granular layer, Malpighian layer), dermis, hair and hair follicle, sebaceous gland, erector muscle, sweat gland and duct, sweat pore, blood capillaries, nerve endings/sense receptors, subcutaneous fat
Long-sighted people see far objects clearly; the image of near objects forms behind the retina.
(a) Describe briefly the female reproductive system of a named mammal (A diagram is essential).
(b) List three differences between reproduction in mammals and in amphibians
(c) Describe the structure and function of the male reproductive organ of a flowering plant.
(a) Named mammal (e.g. human/rabbit); labelled diagram: two ovaries, oviducts (Fallopian tubes) with funnels, uterus, cervix, vagina, vulva
Ovaries produce ova and hormones; the funnel collects the ovum; fertilisation occurs in the oviduct; the embryo implants and develops in the uterus; vagina receives the penis and is the birth canal
(b) Any three: mammals – internal fertilisation, amphibians – external; mammals – young develop in the uterus (viviparous), amphibians – eggs laid in water; mammals – few eggs, amphibians – many eggs; mammals – placenta and parental care with milk, amphibians – no placenta and little care; amphibians have a larval (tadpole) stage and metamorphosis
(c) The stamen: a stalk (filament) carrying an anther; the anther has four pollen sacs where pollen grains are produced by meiosis; the filament supports the anther and carries water and food to it; anther splits open (dehisces) to release pollen for pollination
A labelled diagram is required in (a).
(a) Mention six ways by which the government is contributing towards self-sufficiency in food production
(b) List five methods of conserving soil fertility
(c) Explain how three named agricultural practices can destroy the balance of an ecosystem.
(a) Any six: loans/credit to farmers; subsidised fertilizers and agro-chemicals; supplying improved seeds and seedlings; agricultural research institutes; extension services/teaching farmers; irrigation schemes and river basin authorities; building rural roads and storage facilities; programmes such as Operation Feed the Nation/Green Revolution; guaranteed prices/marketing; mechanisation (tractor hire)
(b) Any five: crop rotation; adding manure/compost; use of fertilizers; planting legumes/cover crops; mulching; bush fallowing; contour ploughing and terracing; avoiding bush burning; mixed farming
(c) Any three: bush burning – kills soil organisms and wildlife, destroys humus, exposes soil to erosion; deforestation/land clearing – destroys habitats, causes erosion and changes climate; overgrazing – removes plant cover, leads to erosion and desertification; misuse of pesticides/herbicides – kills useful organisms, pollutes water and food chains; monocropping – exhausts nutrients and builds up pests; excess fertilizer – runs into water causing eutrophication
Name each practice and say what part of the ecosystem it damages.
(a) Explain the following terms (i) voluntary action (ii) involuntary action
(b) State three functions each of (i) insulin (ii) auxins.
(c) Describe an experiment to show that plant roots respond positively to gravity.
(a)(i) Voluntary action: an action done consciously, by will, controlled by the cerebrum, e.g. writing, walking
(ii) Involuntary action: an automatic action not under conscious control, e.g. heartbeat, breathing, reflexes like blinking
(b)(i) Insulin: lowers blood sugar; makes the liver and muscles change glucose to glycogen; increases uptake of glucose by cells; increases oxidation of glucose; promotes conversion of glucose to fat
(ii) Auxins: cause cell elongation/growth; control tropisms; promote root formation in cuttings; cause fruit development without fertilisation; prevent leaf and fruit fall; apical dominance
(c) Pin germinating seedlings (e.g. bean) with straight radicles horizontally on moist cotton wool/cork in a gas jar or on a klinostat; keep one klinostat still (experiment) and one rotating (control); keep in the dark for 2–3 days
Result: radicles on the still one curve downwards; radicles on the rotating klinostat grow straight
Conclusion: roots are positively geotropic
Give an example with each definition in (a).