47 questions. Try each one, then open the answer to check yourself and read the explanation.
Viruses are considered to be living organisms because they
Answer: A (possess transmittable characters)
Viruses carry genetic material and reproduce inside host cells, passing their characters on to new viruses; this is why they are counted as living.
Which of the following characteristics is common to Amoeba and Paramecium?
Answer: C (Contractile vacuole)
Both are freshwater protozoa that use a contractile vacuole to pump out excess water; oral groove, trichocysts and cilia belong only to Paramecium.
Hydra removes undigested food by
Answer: B (passing it through the mouth)
Hydra's gut has only one opening, so undigested food goes out through the mouth.
Which of the following groups of invertebrates reproduces by budding?
Answer: D (Coelenterata)
Coelenterates such as Hydra grow buds on their body that break off as new individuals.
The algae, bryophytes and pteriodophytes are similar in that they
Answer: C (require moisture for fertilization)
In all three groups the male gametes swim to the egg, so water is needed for fertilization. Pteridophytes do have vascular tissue.
The spores of ferns are dispersed by
Answer: D (explosive mechanism)
When the fern sporangium dries, its annulus straightens and then snaps back, flinging the spores out explosively.
In bryophytes, sex organs are produced in the
Answer: A (gametophyte)
The leafy moss plant is the gametophyte, and it carries the antheridia and archegonia.
Use the figure (a twig) to answer: Which part of the twig produces auxins?
Answer: D (1)
Auxins are made at the growing tip, the terminal bud labelled 1.
Which of the following animals has homodont dentition?
Answer: C (Lizard)
A lizard's teeth are all of the same type (homodont); mammals like rats and man have different types, and pigeons have no teeth.
In which of the following does external fertilization take place?
Answer: A (Toad)
Toads shed eggs and sperm into water, where fertilization takes place outside the body.
In the tapeworm, the suckers on the scolex are used for
Answer: B (holding fast to the host)
The suckers and hooks on the head grip the gut wall of the host so the worm is not swept away.
A feature which adapts birds to flight is the possession of
Answer: B (light bones)
Hollow, air-filled bones make a bird light enough to fly.
The nephridia in the earthworm form part of the
Answer: D (excretory system)
Nephridia are the earthworm's excretory organs, removing nitrogenous waste from each segment.
Which of the following diseases is rarely spread by a housefly?
Answer: A (Yellow fever)
Yellow fever is spread by the Aedes mosquito; houseflies carry germs of dysentery, typhoid and polio on their bodies to food.
Which of the following cells is thin-walled and living at maturity?
Answer: B (Sieve tube)
Sieve tubes have thin cellulose walls and remain living. Collenchyma walls are thickened at the corners; xylem vessels and sclerenchyma are dead and thick-walled.
The mode of nutrition in which digestion is extracellular is
Answer: D (saprophytic)
Saprophytes such as Mucor release enzymes onto their food and absorb the digested products, so digestion happens outside the organism.
The first step in the process of photosynthesis is the
Answer: A (activation of the chlorophyll)
Photosynthesis starts when chlorophyll absorbs light energy and becomes activated; this energy then splits water.
The organ which secretes digestive enzymes as well as a hormone is the
Answer: C (pancreas)
The pancreas makes digestive enzymes (amylase, lipase, trypsin) and the hormone insulin.
The villus in the small intestine is significant because it
Answer: A (increases the surface area for absorption)
Millions of finger-like villi give the small intestine a huge surface for absorbing digested food.
If a ring of bark and phloem is removed from a stem, the
Answer: D (movement of mineral salts is hardly affected)
Ringing removes the phloem but leaves the xylem, so water and mineral salts still move up; only food transport is cut.
Transpiration can be measured with a
Answer: C (potometer)
A potometer measures how fast a leafy shoot takes up water, which shows the rate of transpiration.
Excretory products responsible for the red, purple and blue colours of flowers are called
Answer: C (anthocyanins)
Anthocyanins are the water-soluble pigments that give red, purple and blue colours.
Etiolation is caused by the influence of
Answer: D (light)
Plants grown without light become etiolated: pale, with long thin stems and small leaves.
Muscles are indirectly attached to bones by means of
Answer: C (tendons)
Tendons are tough, inelastic cords that join muscles to bones; ligaments join bone to bone.
Use the figure (a kidney tubule) to answer: Which structure is the glomerulus?
Answer: C (2)
The glomerulus is the knot of capillaries inside the cup of Bowman's capsule, which is the part labelled 2.
Use the figure (a kidney tubule) to answer: If the blood is too concentrated, more water is absorbed from
Answer: B (4)
When the blood is too concentrated, ADH makes the tubule and collecting duct walls reabsorb more water; the tubule is the part labelled 4.
During mammalian embryo development, large amounts of oestrogen and progesterone are produced in the
Answer: C (placenta)
From about the third month of pregnancy the placenta produces oestrogen and progesterone, which keep the pregnancy going.
Use the figure (transverse section of an ovary): The type of placentation shown in the figure above is
Answer: A (parietal)
The ovules are attached to the inner wall of a one-chambered ovary, which is parietal placentation.
Fruits which develop without fertilization are described as
Answer: B (pathenocarpic)
Parthenocarpic fruits, like some bananas, form without fertilization and so have no seeds.
The elephant grass is propagated vegetatively by means of
Answer: D (solons)
Elephant grass spreads by stolons and runners (creeping stems) that root at the nodes.
Use the figure (a reflex arc) to answer: In a reflex action, impulse flows from
Answer: A (1 to 2)
The impulse travels along the sensory neuron, through the ganglion (1), into the spinal cord (2) and then out along the motor neuron.
The part of the ear that is concerned with balance is the
Answer: A (semi-circular canals)
The fluid in the semicircular canals moves when the head moves, and this is sensed for balance.
In an organism where the 2n number of chromosomes is 16, the number of chromosomes in each gamete will be
Answer: C (8)
Gametes are haploid (n), so they have half of 16, which is 8.
What would be the result of the first filial generation (F1) and the second filial generation (F2) of a monohybrid cross between pure line normal-winged Drosophila flies and pure line short-winged flies, if the gene for the normal wing is dominant?
Answer: D (F1 flies all normal-winged and three-quarters of F2 flies are normal-winged)
NN × nn gives all Nn (normal) in F1; Nn × Nn gives 3 normal : 1 short in F2.
Use the figure (cell division): What stage during cell division is represented in the figure above?
Answer: C (Anaphase)
The arrows show chromatids being pulled apart to opposite poles on the spindle, which happens in anaphase.
An individual in the AB blood group is a universal recipient for blood donation because
Answer: D (there are no anti-A and anti-B antibodies in the serum)
Group AB plasma has no anti-A or anti-B antibodies, so donated cells of any group are not clumped.
Haemophilia results from the mutation of the genes
Answer: C (which control the mechanism for blood-clotting)
Haemophilia is a failure of blood clotting caused by a faulty gene for a clotting factor.
In a savanna ecosystem the abiotic factors include
Answer: B (water, temperature and soil)
Abiotic factors are non-living; water, temperature and soil are all non-living, while legumes, reptiles and grasses are living.
Use the diagram (a food web) to answer: Which organism is an omnivore?
Answer: C (Mouse)
The arrows show the mouse eating maize (a plant) as well as grasshoppers and weevils (animals), so it is an omnivore.
Use the diagram (a food web) to answer: Which of the organisms will have the lowest population in an ecosystem?
Answer: A (Hawk)
The hawk is the top carnivore; energy is lost at each level, so the top of the web supports the fewest individuals.
The salinity of a brackish environment
Answer: D (increases during the dry season)
In the dry season less fresh water flows in and more water evaporates, so the water becomes saltier.
Physiological adaptation to very dry condition in animals is called
Answer: B (aestivation)
Aestivation is the inactive state some animals enter to survive hot, dry periods. Xeromorphism is a structural adaptation of plants.
Which set of diseases is spread mainly by insect vectors?
Answer: D (Malaria, cholera and river blindness)
Malaria (mosquito) and river blindness (blackfly) are insect-borne, and houseflies help spread cholera; the other sets are spread mainly by contact, air or food.
Which of the following constitutes pollution?
Answer: B (Loud disco music)
Very loud music is noise pollution, which can damage hearing and disturb others.
An acidic soil can be improved upon by
Answer: C (flocculation)
Adding lime neutralises acidity and makes clay particles clump together (flocculation), which improves the soil.
What do bacteria in root nodules derive from the host plant?
Answer: D (Protection and carbodydrates)
Rhizobium lives sheltered inside the nodule and gets sugars from the plant, while it gives the plant fixed nitrogen.
Free nitrogen is released to the atmosphere by
Answer: C (denitrifying bacteria)
Denitrifying bacteria break down nitrates and release nitrogen gas back into the air.