65 questions. Try each one, then open the answer to check yourself and read the explanation.
The following life processes are common to both plants and animals except
Answer: D (photosynthesis)
All living things respire, grow and reproduce, but only green plants (and some protists) carry out photosynthesis.
Which of these organelles is common to both plant and animal cells?
Answer: C (Mitochondrion)
Both plant and animal cells respire, so both have mitochondria; chloroplasts and pyrenoids are only in plants, and centrioles only in animals.
The epidermis of the mammalian skin is an example of a tissue because the cells
Answer: B (have a similar structure and function)
A tissue is a group of similar cells that work together to do the same job.
Which of the following statements is correct about organs?
Answer: B (They perform a certain overall function)
An organ is made of several tissues working together to carry out one overall function, like the heart pumping blood.
The structure used for movement in Amoeba is
Answer: B (pseudopodia)
Amoeba moves by pushing out finger-like extensions of its cytoplasm called pseudopodia (false feet).
Which of the following parts of a cell is not an organelle?
Answer: C (Cell wall)
Organelles are structures inside the cytoplasm; the cell wall is a non-living layer outside the cell membrane.
The folded portion of mitochondrion is called
Answer: A (cristae)
The inner membrane of a mitochondrion is folded into cristae, which give a large surface for respiratory enzymes.
The physical process which occurs when a red blood cell is placed in distilled water causing it to burst and break down is known as
Answer: D (haemolysis)
Water enters the red cell by osmosis until it bursts, because it has no cell wall; this bursting is haemolysis.
During the process of osmosis a semi-permeable membrane allows
Answer: C (only solvent molecules to pass through it)
A semi-permeable membrane lets small solvent (water) molecules through but holds back the larger solute molecules.
Which of the following environmental conditions is ideal for plant cells to remain turgid?
Answer: D (Cool, humid weather)
In cool, humid weather transpiration is slow, so the cells lose little water and stay full and turgid.
Which of the following processes does not contribute towards growth?
Answer: D (Cell plasmolysis)
Plasmolysis is the shrinking of a cell's contents when it loses water; it does not add to growth.
The aspects of growth in living organisms include all the following processes except
Answer: B (reversible increase in size)
Growth is a permanent (irreversible) increase in size and dry weight; a reversible increase, like a cell swelling with water, is not growth.
Support in young herbaceous plants is provided by
Answer: C (turgidity)
Young herbaceous plants have little wood; their cells are kept firm by water pressure (turgidity), which holds the plant up.
Which of the following heart structures is best adapted to cope with double circulation?
Answer: D (Two auricles and two ventricles)
Four chambers keep oxygenated and deoxygenated blood completely apart, so the right side pumps to the lungs and the left side to the body.
Which of these factors does not contribute towards the ascent of water in plants?
Answer: D (Turgor pressure)
Water rises in the xylem by root pressure, capillarity and transpiration pull; turgor pressure keeps cells firm but does not lift water.
The ventricles of the mammalian heart have thicker muscular walls than the auricles because the
Answer: C (ventricles pump blood to longer distances)
Auricles only push blood into the ventricles below them, but ventricles must pump it to the lungs and all round the body, so they need thicker muscle.
Gaseous exchange occurs through the following structures in some organisms except
Answer: D (chloroplast and plastids)
Chloroplasts and other plastids are organelles for making or storing food; they are not breathing surfaces.
Which of the following organs in mammals is not excretory in function?
Answer: C (Pancreas)
The pancreas makes digestive juice and hormones; the liver (bile pigments), kidney (urine) and lungs (carbon dioxide) all excrete.
Which of the following substances is not an excretory product in mammals?
Answer: C (Faeces)
Faeces are mostly undigested food that never entered body cells, so removing them is egestion, not excretion.
An organism which maintains a constant temperature irrespective of environmental temperature fluctuation is
Answer: B (a mammal)
Mammals (and birds) are warm-blooded (homoiothermic) and keep their body temperature steady whatever the surroundings.
Which of the following conditions is responsible for the presence of sugar in the blood of diabetic patients?
Answer: B (Low production of insulin)
Insulin lets cells take up glucose and the liver store it; too little insulin leaves the blood sugar high (diabetes mellitus).
The central nervous system in humans is made up of the
Answer: D (brain and spinal cord)
The CNS is only the brain and spinal cord; the nerves that branch from them form the peripheral nervous system.
The part of the ear in mammals responsible for the detection of sound is the
Answer: C (cochlea)
The cochlea in the inner ear holds the sensory cells that change sound vibrations into nerve impulses; the tympanum only vibrates.
Which of the following statements best describes pollination? The transfer of pollen grain from
Answer: A (anther to stigmas)
Pollination is the transfer of pollen grains from an anther to a stigma, of the same flower or another flower of the same species.
Which of the following vertebrae provide articulating surfaces for the ribs?
Answer: A (Thoracic)
Thoracic vertebrae have facets on their centrum and transverse processes where the ribs join.
Which of the following is not a component of the appendicular skeleton?
Answer: B (Atlas)
The atlas is the first neck vertebra, part of the axial skeleton; the limbs and girdles form the appendicular skeleton.
If the mucus in the air track of mammals dry up and the hairs in the nostrils are removed
Answer: A (impure air would be breathed into their lungs)
Nostril hairs and mucus trap dust and germs; without them dirty air would reach the lungs.
A one-seeded fruit in which the pericarp has fused with the seed coat is classified as
Answer: B (a caryopsis)
In a caryopsis, such as a maize grain, the fruit wall is joined to the seed coat; in an achene they stay separate.
Study the following list of deficiency symptoms in animals:
I. Loss of appetite and weight; II. Delayed healing of wounds; III. Rickets; IV. Sterility in animals; V. Failure of blood to clot; VI. Night blindness
Which of the following deficiencies is caused by lack of vitamin A
Answer: D (VI)
Vitamin A is needed to make the light-sensitive pigment in the rods, so lack of it causes night blindness.
Study the following list of deficiency symptoms in animals:
I. Loss of appetite and weight; II. Delayed healing of wounds; III. Rickets; IV. Sterility in animals; V. Failure of blood to clot; VI. Night blindness
Which of the following vitamins would correct the deficiency numbered V?
Answer: A (Vitamin K)
Vitamin K is needed by the liver to make clotting factors, so it corrects failure of blood to clot.
Study the following list of deficiency symptoms in animals:
I. Loss of appetite and weight; II. Delayed healing of wounds; III. Rickets; IV. Sterility in animals; V. Failure of blood to clot; VI. Night blindness
Which of the following combination of food substances would correct the deficiency numbered II?
Answer: A (Tomatoes, oranges and mangoes)
Slow wound healing is a sign of vitamin C deficiency (scurvy), and fresh fruits such as tomatoes, oranges and mangoes are rich in vitamin C.
Which of the following food substances would produce a translucent mark when rubbed on a white paper?
Answer: D (Groundnut)
The translucent (grease) spot test shows fats and oils; groundnut is rich in oil.
If an enzyme works best in an acid medium, in which of the following parts of the human gut is the pH best for enzyme activities? In the
Answer: B (stomach, pH 2.0)
The stomach contains hydrochloric acid and has a pH of about 2, the only acid region listed.
Which of the following organisms is not considered as a parasitic plant?
Answer: B (Rhizopus)
Rhizopus is a fungus that feeds saprophytically on dead matter; Cassytha, dodder and mistletoe are parasitic flowering plants.
The examples of autotrophic organisms include the following except
Answer: C (Hydra)
Hydra is an animal that catches small prey with its tentacles, so it is heterotrophic; the others have chlorophyll.
Which of the following organisms feeds both autotrophically and heterotrophically?
Answer: D (Euglena)
Euglena photosynthesises with its chloroplasts in light, but in darkness it can absorb food like an animal.
Siphons and gills are structures in aquatic organisms used for
Answer: A (gaseous exchange)
Water is drawn in through siphons and passes over the gills, where oxygen is taken in and carbon dioxide given out.
The first step in carrying out ecological studies in a terrestrial habitat is
Answer: B (mapping the area)
Before sampling or measuring anything, the area is surveyed and mapped so that sampling sites can be chosen.
Which of the following components of an ecosystem does not contribute to the biomass of the system?
Answer: D (Habitat)
Biomass is the mass of living organisms; the habitat is the non-living place where they live.
The physical and chemical factors which affect the life of organisms in an environment are described as
Answer: C (abiotic)
Abiotic factors are the non-living physical and chemical factors such as temperature, light, pH and rainfall.
The group of several populations that interact and share a habitat, form
Answer: B (a community)
A community is all the populations of different species living and interacting in one habitat.
Which of these factors are common to both aquatic and terrestrial habitats?
Answer: C (Light, rainfall and temperature)
Light, rainfall and temperature affect both land and water; turbidity, tide and salinity are features of water only.
Organisms that feed essentially on plants within any ecosystem may be referred to as
Answer: B (herbivores)
Herbivores are plant eaters (primary consumers).
If a pond contains water weed, tadpoles, Tap-minnows (fish) and is visited after by Herons (bird) what would be the possible food chain?
Answer: B (Water weed → Tadpole → Tap-minnow → Heron)
The water weed is the producer, tadpoles eat the weed, small fish eat the tadpoles, and herons eat the fish.
Which of the following statements about feeding relationships is correct?
Answer: B (In a food chain on land, green plant is the producer)
Green plants make food from sunlight, so they are the producers that start land food chains.
Which of these diseases cannot be spread by an insect?
Answer: D (Measles)
Measles spreads by droplets from an infected person; houseflies can carry cholera germs, mosquitoes spread malaria and tsetse flies spread trypanosomiasis.
Which of the following orders correctly represents the trend in eutrophication?
Answer: B (Excess nitrates and phosphates → Massive algal growth → Lack of oxygen → Death of aquatic organisms)
Extra nutrients cause algae to grow rapidly; when they die, decomposers use up the oxygen and fish and other organisms die.
Air pollution can be reduced by the following methods except
Answer: D (recycling tins, cans and bottles)
Recycling tins, cans and bottles mainly reduces solid waste (land pollution); the other methods deal with harmful gases in the air.
An effective management of natural resources to ensure their continued yield from generation to generation involve all the following except
Answer: D (disposal of raw sewage into the sea)
Dumping raw sewage pollutes the sea and harms its living resources, so it is not good management.
The following practices can contribute towards the conservation of natural resources except
Answer: B (deforestation)
Deforestation is the clearing of forests, which destroys resources and habitats.
Variation is a factor which
Answer: A (differentiates between individuals of the same species)
Variation means the differences between individuals of the same species, such as height and blood group.
Which of the following traits in humans is not a morphological variation?
Answer: D (Ability to roll the tongue)
Tongue rolling is an ability (physiological variation), while height, head shape and skin colour are visible body features.
The blood group in humans referred to as a universal recipient is
Answer: D (AB)
Group AB has no anti-A or anti-B antibodies in its plasma, so it can receive blood of any group.
If a heterozygous red flowered plant, (Rr) was self fertilized, the offspring would be expected to be
Answer: C (red flowered, white flowered plants)
Rr × Rr gives RR, Rr, Rr and rr, so three red-flowered plants to one white-flowered plant.
The contrasting pair of genes affecting a trait and located at the same position on homologous chromosomes is referred to as
Answer: C (alleles)
Alleles are different forms of the same gene found at the same locus on a pair of homologous chromosomes.
If a pure breeding white cat (homozygous dominant) mates with a pure breeding black cat (recessive), what would be the fur colour of the F1 generation?
Answer: C (Heterozygous white)
WW × ww gives only Ww kittens: heterozygous, and white because white is dominant.
Courtship behaviour in animals may include all of the following except
Answer: D (basking in the sun by a lizard)
A lizard basks in the sun to warm its body; this controls body temperature and is not courtship.
Honey-bee workers carry out the following functions except
Answer: A (laying eggs)
Workers are sterile females; only the queen lays eggs.
The long necks and legs of the present day giraffes were some of the basis of
Answer: C (Lamarck's theory of evolution)
Lamarck used the giraffe's neck to explain use and disuse and the inheritance of acquired characters.
(a) (i) List the functions of a typical foliage leaf.
(ii) Name three types of leaf modifications giving one example in each case.
(b) Make a diagram 8 – 10cm long, of the female reproductive part of a flowering plant and label fully.
(c) Name three plants that are pollinated by insects.
(a)(i) Photosynthesis (making food); transpiration; gaseous exchange through stomata; respiration; storage of food or water in some plants; excretion of waste (e.g. in falling leaves); vegetative propagation in some plants.
(ii) Any three with example: tendrils – Gloriosa, garden pea; spines – cactus (Opuntia), Euphorbia; storage (fleshy) leaves – onion; scale leaves – onion, ginger; insect-catching leaves – pitcher plant (Nepenthes), sundew, bladderwort; hooks – Bignonia; leaves for vegetative propagation – Bryophyllum.
(b) Diagram 8–10 cm of the carpel/pistil, title given, labels on ruled guidelines: stigma, style, ovary, ovule, ovary wall, receptacle (and placenta).
(c) Any three: Hibiscus, flamboyant (Delonix), cowpea, Crotalaria, Clitoria, sunflower, orchid, pride of Barbados.
Diagram: draw only the female part, large and labelled.
(a) (i) Describe three features of a typical vertebra.
(ii) Name three types of skeletons found in animals, and in each case name one animal which possesses it.
(b) (i) State four functions of the mammalian skeleton.
(ii) Name four types of joints found in the mammalian skeleton.
(a)(i) Any three: centrum – solid body that bears weight; neural canal – hole through which the spinal cord passes; neural arch – roof over the neural canal; neural spine – for muscle attachment; transverse processes – for muscle (and rib) attachment; zygapophyses (facets) – join one vertebra to the next.
(ii) Hydrostatic skeleton – earthworm; exoskeleton – cockroach, grasshopper, crab; endoskeleton – man, dog, fish.
(b)(i) Any four: support and shape; protection of delicate organs; movement/locomotion; production of blood cells; storage of calcium and phosphate; muscle attachment; breathing (ribs).
(ii) Any four: ball and socket; hinge; pivot; gliding; fixed/immovable (suture); slightly movable (cartilaginous).
Give an example animal for each skeleton type.
(a) Write short notes on each of the following:
(i) ecosystem; (ii) population; (iii) ecological succession in plants
(b) List five ways by which nitrogen can be made available to the soil for plant growth.
(a)(i) Ecosystem: a natural unit made of a community of living organisms interacting with each other and with their non-living environment, e.g. a pond or forest; it is self-sustaining, with energy flow and nutrient cycling.
(ii) Population: all the organisms of one species living in a particular area at a particular time; it can be described by its size, density, distribution and growth.
(iii) Ecological succession: the gradual, orderly change in the plant species of an area over time; pioneer plants (e.g. lichens, mosses) colonise bare ground, change the conditions, and are replaced by grasses, shrubs and then trees until a stable climax community forms.
(b) Any five: nitrogen fixation by free-living bacteria (Azotobacter, Clostridium); fixation by Rhizobium in root nodules of legumes; fixation by blue-green algae (Nostoc, Anabaena); lightning combining nitrogen and oxygen, washed down by rain; decomposition (ammonification) of dead organisms and wastes; nitrification of ammonium compounds to nitrates; adding fertilizers/manure/compost; animal urine and droppings.
Succession: name the stages from pioneer to climax.
(a) Explain the term conservation of natural resources.
(b) (i) List seven methods of soil conservation.
(ii) Name four other natural resources that may be conserved.
(c) State three factors which negatively affect conservation of forest in West Africa.
(d) Describe what happens during the denitrification stage of the nitrogen cycle.
(a) Conservation of natural resources is the careful management and wise use of resources such as soil, water, forests and wildlife so they are protected from waste and destruction and remain available for future generations.
(b)(i) Any seven: crop rotation; cover cropping; contour ploughing; terracing; mulching; adding manure/compost; strip cropping; afforestation/planting windbreaks; avoiding bush burning; avoiding overgrazing; bush fallowing; building ridges across slopes; avoiding excessive tillage.
(ii) Any four: water; forests; wildlife; minerals; fossil fuels (oil, coal); air; fisheries.
(c) Any three: indiscriminate felling of trees (logging); bush burning; shifting cultivation/farming; urbanisation and road building; overgrazing; mining; fuelwood collection; poor enforcement of forest laws; population pressure.
(d) Denitrifying bacteria (e.g. Pseudomonas, Thiobacillus denitrificans) break down nitrates in the soil.
The nitrates are converted to nitrogen gas, which escapes into the atmosphere.
This happens mostly in waterlogged, poorly aerated soils, and makes the soil lose nitrogen.
Soil conservation: list practical farm methods.
(a) What is a hormone?
(b) Outline the role played by adrenaline in an emergency situation.
(c) In a tabular form, list five differences between hormonal co-ordination and nervous co-ordination.
(d) Name three animal hormones and two plant hormones.
(a) A hormone is a chemical messenger made by an endocrine (ductless) gland, carried in the blood to a target organ where it produces a response.
(b) Adrenaline prepares the body for 'fight or flight': heart beats faster and stronger; breathing rate rises; liver changes glycogen to glucose, raising blood sugar; blood is diverted to the muscles; pupils widen; hairs stand on end; the person becomes alert.
(c) Hormonal vs nervous: chemical message vs electrical impulse; carried in blood vs carried along nerves (neurons); slow vs fast; response lasts long vs short-lived; effect may be widespread vs localised to particular muscles or glands; under involuntary control vs can be voluntary or involuntary.
(d) Animal (any three): insulin, adrenaline, thyroxine, oestrogen, testosterone, glucagon, growth hormone. Plant (any two): auxin (IAA), gibberellin, cytokinin, abscisic acid, ethylene.
Use a two-column table for (c).
(a) (i) Briefly explain the term respiration.
(ii) Name the two types of respiration and write a balanced equation to summarize each of them.
(b) Outline the mechanisms involved in: (i) inhalation; (ii) exhalation in human beings.
(a)(i) Respiration is the breaking down of food (mainly glucose) in living cells to release energy, with carbon(IV) oxide and water (or alcohol/lactic acid) as by-products.
(ii) Aerobic respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (2898 kJ).
Anaerobic respiration: in yeast C6H12O6 → 2C2H5OH + 2CO2 + energy (210 kJ); in muscle C6H12O6 → 2C3H6O3 (lactic acid) + energy.
(b)(i) Inhalation: external intercostal muscles contract, pulling the ribs upwards and outwards; diaphragm muscles contract and the diaphragm flattens; the volume of the thorax increases and pressure in the lungs falls below atmospheric pressure; air rushes in through the nose and trachea into the lungs.
(ii) Exhalation: external intercostal muscles relax (internal ones contract) and the ribs move down and inwards; diaphragm relaxes and domes upwards; volume of the thorax decreases and pressure in the lungs rises; air is forced out.
Link volume change to pressure change.