50 questions. Try each one, then open the answer to check yourself and read the explanation.
Use the figure (a cell) to answer: The structure labelled 5 is the
Answer: B (Golgi body)
Structure 5 is a stack of curved, flattened sacs with small vesicles at the edges, which is the Golgi body.
Use the figure (a cell) to answer: Which of the labelled parts of the cell contains ribonucleic acid?
Answer: C (3)
Part 3 is the nucleolus, which is made largely of RNA and is where ribosomal RNA is produced.
Use the figure (a cell) to answer: Which structure is known as the power house of the cell?
Answer: C (4)
Structure 4 has a folded inner membrane (cristae): it is a mitochondrion, where respiration releases energy.
When a virus is placed in a non-living medium it
Answer: D (becomes crystallized)
Outside a living cell a virus shows no life activity and can exist as an inert crystal.
A characteristic of the phylum coelenterata is that
Answer: B (they possess a gut with a single opening)
Coelenterates like Hydra have a sac-like gut with only one opening, the mouth; they are radially symmetrical, and pores are a feature of sponges.
A multinucleate body without internal cell boundaries is characteristic of
Answer: B (fungi)
Fungi such as Mucor have hyphae with many nuclei and no cross walls (coenocytic).
Double fertilization is a unique feature of
Answer: A (angiosperms)
Only flowering plants have double fertilization: one male nucleus fuses with the egg and the other with the polar nuclei to form endosperm.
Which of the following phyla have members with both internal and external segmentation?
Answer: C (Annelida)
In annelids like the earthworm the rings on the outside match internal partitions (septa) dividing the body cavity.
Mineral salts can be absorbed into the roots by
Answer: C (diffusion and active transport)
Ions enter root hairs by diffusion when more concentrated outside, and by active transport (using energy) against a concentration gradient. Osmosis moves only water.
Which of the following is a common characteristic of crustaceans?
Answer: B (Possession of two pairs of antennae)
Crustaceans such as crayfish have two pairs of antennae (antennae and antennules); insects have one pair.
The pedipalpi in spiders are used for
Answer: A (grasping)
Pedipalps are the small leg-like parts beside the mouth that spiders use to hold and handle their prey.
The body of a snail is divided into head,
Answer: D (visceral mass and foot)
A mollusc's body has a head, a muscular foot and a visceral mass holding the organs, covered by the mantle and shell.
Use the figure (mouth parts of a butterfly) to answer: Which of the labelled parts is used for feeling?
Answer: A (1)
Part 1 is the antenna, the butterfly's organ of touch and smell.
Use the figure (mouth parts of a butterfly) to answer: The structure labelled 2 is the
Answer: D (labial palp)
Part 2 is the short hairy projection beside the proboscis, the labial palp.
In a dicotyledonous stem, each companion cell is found beside the
Answer: C (sieve tube)
Companion cells lie next to sieve tubes in the phloem and control their activities.
Use the figure (four teeth labelled 1 to 4) to answer: Which of the structures is the molar?
Answer: A (1)
Tooth 1 has a broad, ridged crown and two roots, the shape of a molar used for grinding.
Use the figure (four teeth labelled 1 to 4) to answer: What is the function of 3?
Answer: B (seizure and tearing of prey)
Tooth 3 is long, pointed and single-rooted, a canine, which holds and tears prey.
If a healthy potted plant is continuously kept in dim light
Answer: A (the rate of respiration may equal that of photosynthesis)
In dim light photosynthesis slows until it just balances respiration (the compensation point), so no extra food or oxygen is produced.
The pancreatic juice contains the enzymes amylopsin,
Answer: C (steapsin and trypsinogen)
Pancreatic juice contains amylase (amylopsin), lipase (steapsin) and trypsinogen. Pepsin and rennin come from the stomach, ptyalin from saliva.
Aged erythrocytes are destroyed in the
Answer: B (liver)
Old red blood cells are broken down in the liver (and spleen); the haemoglobin is turned into bile pigments.
The seedlings in a rice field were found to have thin lanky growth with reddish leaves and poor root development. This is because the soil lacks
Answer: B (phosphorus)
Phosphorus shortage causes poor root growth, stunted thin stems and purplish-red leaves.
There will be agglutination when the
Answer: B (Group A serum mixes with Group B erythrocytes)
Group A serum contains anti-B antibodies, which clump red cells carrying antigen B.
Which of the following is the function of lymph?
Answer: B (Transports nutrients and oxygen from blood capillaries to the cells)
Lymph (tissue fluid) bathes the cells and passes food and oxygen from the capillaries to them.
Use the figure (bones of the forelimb) to answer: The type of joint at the point labelled 5 is the
Answer: D (hinge joint)
Point 5 is the elbow, a hinge joint that moves in one plane only.
Use the figure (bones of the forelimb) to answer: Which of the labelled bones is the ulna?
Answer: B (3)
Bone 3 carries the olecranon process at the elbow, so it is the ulna; bone 4 is the radius and 1 is the humerus.
Use the figure (bones of the forelimb) to answer: What is the name of the structure labelled 2?
Answer: B (Olecranon process)
Structure 2 is the projection of the ulna behind the elbow, the olecranon process, which stops the arm over-straightening.
The lumbar vertebra when compared wtih a thoracic vertebra has a
Answer: C (thicker centrum)
Lumbar vertebrae carry much of the body's weight, so they have a large, thick centrum.
Wind-pollinated flowers usually have
Answer: D (long styles)
Wind-pollinated flowers hang their stigmas out on long styles to catch pollen from the air; their pollen is smooth and light.
The components of castor oil seed and the maize grain are similar EXCEPT for the
Answer: A (number of cotyledons)
Castor is a dicot with two cotyledons; maize is a monocot with one. Both have one radicle and one plumule.
A corm differs from a bulb in that
Answer: A (its stem is the main food storage organ)
A corm stores food in its swollen stem; a bulb stores food in fleshy leaves around a small disc-shaped stem.
Exponential increase in the population of an organism is a characteristic feature of
Answer: A (binary fission)
In binary fission each cell divides into two, then four, then eight, so numbers double every generation.
The irreversible life process by which new protoplasm is added to increase the size and weight of an organism can be termed
Answer: C (growth)
Growth is the permanent increase in size and dry weight caused by making new protoplasm.
Fruit enlargement can be induced by spraying young ovary with
Answer: D (auxin, cytokinin and gibberellin)
Auxins, gibberellins and cytokinins all promote growth and fruit development; abscisic acid and ethylene promote ripening, ageing and fall.
A fundamental similarity between nervous and hormonal system is that both
Answer: A (involve chemical transmission)
Hormones are chemicals carried in the blood, and nerve impulses cross synapses by chemical transmitters, so both use chemical messages.
The region that controls most of the unconscious processes of a mammalian body is the
Answer: D (medulla oblongata)
The medulla oblongata controls involuntary activities such as breathing, heartbeat and blood pressure.
During cell division, the two strands of chromosomes are joined at a point called
Answer: C (centromere)
The two chromatids of a chromosome are held together at the centromere.
When the two alleles present in an organism are of the the same type, the genotype is described as
Answer: C (homozygous)
Homozygous means both alleles are the same, e.g. TT or tt.
If parents with blood groups AB and OO produce six children
Answer: A (three of them will have group B)
AB × OO gives AO and BO in equal proportion, so on average half of six children, three, will be group B.
Which of the following is a sex-linked character?
Answer: D (Colour blindness)
The gene for colour blindness is carried on the X chromosome, so it is sex-linked.
In an ecosystem, the LEAST efficient energy transfer link is from
Answer: B (sun to producers)
Green plants capture only about 1% of the sunlight falling on them, far less than the roughly 10% passed between feeding levels.
Lichen is an example of
Answer: B (a symbiotic association)
A lichen is an alga and a fungus living together, each benefiting the other: symbiosis.
A physiological adaptation of plants to the problem of excessive water loss is
Answer: B (reversal of the normal stomatal rhythm)
Opening stomata at night and closing them by day is a change in how the plant works (physiological); fewer stomata and waxy cuticle are structural.
Which of the ways of controlling bilharzia can result in pollution?
Answer: D (Applying chemical to kill the snails)
Chemicals (molluscicides) poured into water to kill snails also poison the water and other living things.
Which of the following diseases can be caused by a bacterium?
Answer: D (Syphilis)
Syphilis is caused by the bacterium Treponema; ringworm is a fungus, polio a virus and malaria a protozoan.
Which of the following is a dangerous product of coal burning?
Answer: A (Sulphur dioxide)
Coal contains sulphur, which burns to sulphur dioxide, a poisonous gas that causes acid rain.
5 g of oven dried soil was heated in a furnace for 24 hours. After cooling, it weighed 4.8 g. What is the amount of humus in the soil?
Answer: C (4.0 g per 100 g dry soil)
Humus burnt off = 5 − 4.8 = 0.2 g in 5 g of soil, which is 0.2 × 100/5 = 4.0 g per 100 g.
Most irrigated lands often become unproductive in later years because of
Answer: B (increase in salinity)
Irrigation water evaporates and leaves its dissolved salts behind, so salt builds up in the soil (salinisation) and crops fail.
Farmers practise crop rotation because it
Answer: C (helps to conserve soil fertility)
Growing different crops in turn (including legumes) stops one crop exhausting the same nutrients, so soil fertility is kept.
Use the figure (vegetation profiles P, Q, R and X) to answer: In which of the habitats will the plants show xeromorphic features most prominently?
Answer: A (X)
Profile X has only sparse, short grass, showing the driest habitat, so its plants need the most adaptations against water loss.
Use the figure (vegetation profiles P, Q, R and X) to answer: Which ecological factor exerts the greatest influence on the structure of the profiles?
Answer: D (Climatic)
The change from forest to sparse grass follows falling rainfall, which is a climatic factor.