49 questions. Try each one, then open the answer to check yourself and read the explanation.
The function of endoplasmic reticulum is
Answer: B (intracellular transport of materials)
The endoplasmic reticulum is a network of membrane channels through the cytoplasm that carries materials from one part of the cell to another.
Which of the following features of euglena is found only in animals?
Answer: C (Pellicle)
Euglena is covered by a flexible pellicle instead of a cellulose cell wall, an animal-like feature. Pyrenoids and stored carbohydrate are plant-like.
An organism found on a bare rock surface has features of algae and fungi. The organism is
Answer: B (a lichen)
A lichen is an alga and a fungus living together; it can grow on bare rock and is often the first coloniser there.
In a plant exhibiting alternation of generations, the diploid multicellular stage is known as
Answer: D (sporophyte.)
The diploid generation produces spores by meiosis, so it is called the sporophyte. The haploid generation makes gametes and is the gametophyte.
A characteristic that distinguishes bryophytes from flowering plants is the
Answer: C (absence of vascular tissues)
Bryophytes have no xylem or phloem, while flowering plants have well-developed vascular tissues.
A good example of a disploblastic organism is
Answer: B (hydra)
Hydra's body is made of two cell layers, the ectoderm and endoderm, so it is diploblastic. Earthworms and roundworms have three layers, and amoeba is a single cell.
The function of the clitellum in the earthworm is to
Answer: D (secrete cocoon.)
The clitellum is a thick glandular band that secretes the cocoon in which the earthworm's eggs are laid.
The crayfish is an arthropod because
Answer: D (its body is covered with an exoskeleton made of chitin.)
A chitinous exoskeleton (with jointed limbs) is a feature of all arthropods. A cephalothorax and antennules are found only in some groups, such as crustaceans.
The hypha of Rhizopus is said to be coenocytic because it
Answer: B (has no cross walls)
A coenocytic hypha has no cross walls, so it is one long tube of cytoplasm with many nuclei.
In most true ferns sporangia are grouped into
Answer: D (sori)
On the underside of a fern frond, sporangia are grouped in clusters called sori, each often covered by an indusium.
In the reproduction of mosses, water is essential because
Answer: C (the male gametes must swim to fertilize the ovum)
Moss sperms (antherozoids) have flagella and must swim through a film of water to reach the egg in the archegonium.
In tapeworm, the two structures that run throughout the length of the body are the
Answer: A (nerve cord and the excretory duct)
The nerve cords and excretory canals run continuously through every proglottid. Each proglottid has its own sperm duct and genital pore.
Which of the following is NOT a characteristic of snails?
Answer: B (Chitinous exoskeleton)
A chitinous exoskeleton is a feature of arthropods. The snail's shell is made of calcium carbonate, secreted by the mantle.
In the life history of a butterfly, destruction of crops is caused by the
Answer: C (caterpillar)
The caterpillar (larva) of the butterfly feeds heavily on leaves, damaging crops. The pupa does not feed and butterflies have no nymph stage.
The correct sequence of tissues in the anatomy of a young dicotyledonous stem from the inside to the outside is
Answer: C (pith, xylem, cambium, phloem, collenchyma, parenchyma and epidermis)
From the centre outwards a young dicot stem has pith, then xylem, cambium and phloem in the bundles, then the cortex tissues and finally the epidermis. Only C has the xylem inside the cambium and phloem outside it.
Secondary thickening is initiated in a dicotyledonous stem by the
Answer: D (cambium.)
Cambium cells divide to form a complete ring that produces new xylem inwards and new phloem outwards, which thickens the stem.
In demonstrating the importance of mineral elements in plants, the culture bottle must be darkened to
Answer: A (prevent algal growth in culture solution)
If light reached the culture solution, algae would grow in it and use up the minerals. Covering the bottle keeps the solution free of algae.
The vitamin which is important in the formation of the retina pigment is
Answer: A (vitamin A)
Vitamin A is used to make visual purple (rhodopsin) in the rods of the retina. Lack of it causes night blindness.
Which of the following lists of organs is directly involved in nutrition?
Answer: D (Salivary gland, liver, stomach, villi and colon.)
All the organs in D digest, absorb or help with food. The other lists include organs such as the bronchus, spleen or lungs, which do not.
In the standard experiment to show that oxygen is given off during photosynthesis, sodium bicarbonate is used to
Answer: C (supply carbondioxide for photosynthesis)
Sodium bicarbonate releases carbon dioxide into the water, so the water plant has plenty of carbon dioxide for photosynthesis.
One cubic centimeter of lymph is richer than an equal volume of blood in
Answer: B (leucocytes)
Lymph has no red cells but carries many lymphocytes (white cells) made in the lymph nodes.
The oxidative part of the respiratory process takes place in the
Answer: A (mitochondria)
The oxidation of food with oxygen (aerobic respiration) happens in the mitochondria, which release most of the cell's energy.
Fatigue of leg muscles may occur after riding many kilometers on a bicycle because of
Answer: D (insufficient oxygen.)
When muscles work hard they cannot get enough oxygen, so they respire anaerobically and lactic acid builds up, causing fatigue.
The function of the loop of Henle is to
Answer: C (concentrate sodium chloride in the medulla of the kidney)
The loop of Henle pumps salt (sodium chloride) into the medulla, making it very salty so that water can be drawn out of the collecting ducts and the urine is concentrated.
Use the information in the graph (rate against time of day for plants R, S, T and U) to answer this question. Which of the plants is likely to have broad leaves with thin cuticle?
Answer: A (R)
Plant R shows the highest rate throughout the day. Broad leaves with a thin cuticle lose water fastest, so they would give the highest rate.
Use the information in the graph (rate against time of day for plants R, S, T and U) to answer this question. Which of the plants is likely to be a desert species?
Answer: A (U)
Plant U shows the lowest rate at every time. Desert plants have features that cut down water loss, so they would give the lowest rate.
Sclerenchyma cells are lignified to
Answer: A (strengthen and support the plant)
Sclerenchyma fibres have thick, lignified walls that make them hard and strong, so they support the plant.
The pineapple fruit is best described as
Answer: C (multiple, succulent and indehiscent)
The pineapple forms from a whole inflorescence of many flowers (multiple fruit), is fleshy (succulent) and does not split open (indehiscent).
The flower shown above is
Answer: C (complete, regular, hermaphroditic with inferior ovary)
The flower has sepals, petals, stamens and carpel (complete and hermaphroditic), is symmetrical (regular), and its ovary is sunk below the point where the other parts arise (inferior).
A flower showing radial symmetry is said to be
Answer: D (actinomorphic.)
An actinomorphic flower can be cut into equal halves along more than one plane, i.e. it is radially symmetrical.
A samara differs from a cypsela by having
Answer: A (an extended pericarp)
A samara's pericarp is drawn out into a flat wing for wind dispersal. A cypsela (e.g. Tridax) has a hairy pappus instead.
The plantain reproduces asexually by
Answer: A (suckers)
Plantain and banana produce suckers, new shoots that grow from the underground stem, and these are used to propagate them.
Most cells in higher animals retain their power of division EXCEPT
Answer: B (nerve cells)
Mature nerve cells cannot divide, so damaged nerve tissue is hardly ever replaced.
A severe deficiency of thyroxin results in
Answer: C (cretinism)
Too little thyroxine in a child causes cretinism: stunted growth and poor mental development.
The growth of a coleoptile towards unilateral light source is due to
Answer: B (unequal distribution of auxin)
More auxin collects on the shaded side, so that side grows faster and the coleoptile bends towards the light.
The sequence of ear ossicles from the fenestra ovalis is
Answer: C (stapes, incus and malleus)
The stapes fits into the oval window (fenestra ovalis), the incus is in the middle and the malleus touches the eardrum.
The centre for controlling body temperature in the brain is the
Answer: D (hypothalamus.)
The hypothalamus senses blood temperature and sets off sweating, shivering or changes in blood flow to keep it steady.
Unlike auxins, gibberellins
Answer: B (do not affect leaf and fruit abscission)
Auxins control leaf and fruit fall (abscission), cause rooting and are used as weedkillers. Gibberellins mainly cause stem elongation and do not control abscission.
A gene which expresses itself only in the homozygous condition is
Answer: C (recessive)
A recessive allele is masked by the dominant one, so it shows only when two copies are present (homozygous).
An example of monohybrid inheritance in man is
Answer: D (albinism.)
Albinism is controlled by a single gene with a recessive allele. The others are not simple single-gene characters.
If a plant, homozygous for round and yellow (RR;YY), is crossed with a wrinkled green type (rr:yy) all of the resulting seeds will be
Answer: B (round and yellow)
Every offspring is RrYy. Round and yellow are dominant, so all the seeds are round and yellow.
The ratio of carriers to sicklers in the F1 generation derived from a parental cross of two carriers of haemoglobin S gene is
Answer: C (2:1)
AS × AS gives 1 AA : 2 AS : 1 SS. Carriers (AS) to sicklers (SS) is therefore 2:1.
In which of the following crosses will all the female offspring be colour blind?
Answer: A (colour blind mother x colour blind father)
Daughters get one X from each parent. Only when both parents' X chromosomes carry the colour-blind allele (XcXc × XcY) are all daughters colour blind.
Which of the following relates to edaphic factors?
Answer: D (The influence of soils on plants and animals.)
Edaphic factors are soil factors, such as soil texture, pH and mineral content, and how they affect living things.
Epiphytes growing on the branches of trees provide an example of the relationship known as
Answer: B (commensalism)
Epiphytes gain support and light from the tree without harming it or feeding on it, so it is commensalism.
Poliomyelitis is an infectious disease caused by
Answer: A (virus)
Polio is caused by the poliovirus, which can be prevented by oral polio vaccine.
One of the functions of UNICEF is to
Answer: C (improve the health and nutrition of children and nursing mothers)
UNICEF (the United Nations Children's Fund) works to improve the health, nutrition and welfare of children and mothers.
Nitrifying bacteria are important because they
Answer: D (oxidize ammonium salts to nitrates.)
Nitrifying bacteria (Nitrosomonas and Nitrobacter) oxidise ammonium compounds to nitrites and then to nitrates, which plants can absorb.
The process by which lime is added to clay soils is known as
Answer: B (flocculation)
Lime makes the fine clay particles clump together (flocculate) into larger crumbs, which improves drainage and aeration.