50 questions. Try each one, then open the answer to check yourself and read the explanation.
Use the figure (an animal cell) to answer: Which of the following structures is associated with aerobic respiration?
Answer: D (4)
Structure 4 is a mitochondrion (oval body with folded inner membrane), where aerobic respiration takes place.
Use the figure (an animal cell) to answer: The structure labelled 5 is used for
Answer: C (secretion)
Structure 5 is the Golgi body, which packages substances such as enzymes and mucus for secretion.
Angiosperms and gymnosperms belong to the plant group known as
Answer: D (spermatophyta)
Both produce seeds, so they are seed plants (spermatophyta).
Which of the following are non-green plants?
Answer: B (Fungi)
Fungi have no chlorophyll, so they cannot make their own food.
Sting cells are normally found in
Answer: B (Hydra)
Sting cells (cnidoblasts) on the tentacles are a feature of coelenterates such as Hydra.
Which of the following are differentiated into true roots, stems and leaves?
Answer: C (Pteridophyta)
Ferns (pteridophytes) are the simplest plants with vascular tissue and true roots, stems and leaves; mosses have only rhizoids.
To facilitate gaseous exchange, breathing roots have
Answer: D (lenticels)
Breathing roots (pneumatophores) of mangroves have many lenticels, pores through which air enters.
The annulus of fern sporangium helps in
Answer: A (spore dispersal)
As the annulus dries it tears the sporangium open and flicks the spores out.
One of the features which adapts Paramecium to its environment is the possession of
Answer: C (cilia)
Cilia let Paramecium swim through water and sweep food into its oral groove.
In the earthworm, the cocoon is secreted by the
Answer: D (clitellum)
The clitellum, the swollen band on the earthworm, secretes the cocoon that holds the eggs.
The function of maxillipeds in crayfish is to aid
Answer: C (feeding)
Maxillipeds are mouth appendages that hold and pass food to the jaws.
The respiratory organ in the land snail is the
Answer: B (mantle)
The land snail breathes through its mantle cavity, whose wall is rich in blood vessels and acts as a lung.
Use the figure (a tadpole) to answer: The structure labelled 4 is for
Answer: A (feeding)
Structure 4 is the long, coiled intestine seen through the belly wall, used in feeding (digesting plant food).
Use the figure (a tadpole) to answer: As the tadpole develops, the structure labelled 5
Answer: B (becomes shorter)
Structure 5 is the tail, which is gradually absorbed during metamorphosis, so it becomes shorter.
The gill rakers of fishes take part in
Answer: A (feeding)
Gill rakers are bony projections on the gill arches that strain food particles from the water and keep them away from the gill filaments.
A wide pith with a ring of conducting tissue is characteristic of the root of
Answer: B (maize)
A monocot root such as maize has many xylem and phloem groups in a ring around a large central pith; dicot roots have little or no pith.
Which of the following is formed immediately after the first product of photosynthesis?
Answer: B (Starch)
The first product is sugar (glucose), which is quickly changed into starch for storage.
Use the figure (dissection showing the abdominal cavity of a rat) to answer: In the digestive system, absorption of nutrients into the blood takes place in the part labelled
Answer: C (3)
Digested food is absorbed in the small intestine, the coiled tube labelled 3.
Use the figure (dissection showing the abdominal cavity of a rat) to answer: The gland which produces trypsin, amylase and lipase is labelled
Answer: B (4)
These three enzymes are in pancreatic juice, so the gland is the pancreas, labelled 4.
One of the accessory organs of the digestive system is the
Answer: C (liver)
Accessory digestive organs are not part of the gut tube but help digestion; the liver makes bile.
The element common to protein, carbohydrate and lipid is
Answer: A (hydrogen)
All three are made of carbon, hydrogen and oxygen; nitrogen and sulphur occur only in proteins.
The crown of the mammalian tooth is covered with
Answer: D (enamel)
Enamel, the hardest substance in the body, covers the crown; cement covers the root.
In living cells, insufficient oxygen may cause a breakdown of glucose into
Answer: B (lactic acids)
Without enough oxygen, muscle cells break glucose down only to lactic acid (anaerobic respiration).
Which of the following can bring about the greatest increase in the rate of transpiration?
Answer: D (Reduced humidity)
Dry air (low humidity) makes water vapour diffuse out of leaves faster; the other three slow transpiration down.
Use the figure (U-tube with weak sugar solution in X and strong sugar solution in Y, separated by a semi permeable membrane) to answer: After 30 minutes, the level of sugar solution in the above figure will
Answer: B (rise in Y only)
Water moves by osmosis from the weak solution (X) into the strong solution (Y), so the level in Y rises.
Use the figure (U-tube with a semi permeable membrane) to answer: The process by which water moves from X to Y through the semi-permeable membrane is called
Answer: B (osmosis)
Movement of water from a dilute to a concentrated solution through a semi-permeable membrane is osmosis.
Fibrinogen and prothrombin play important roles in the
Answer: B (clotting of blood)
Prothrombin is turned into thrombin, which changes fibrinogen into fibrin threads that form a clot.
Deoxygenated blood flows into the right and left lungs through the
Answer: C (pulmonary artery)
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs; it is the only artery carrying deoxygenated blood.
Which of the following is a plant excretory product?
Answer: C (Resin)
Resin is a waste product stored by plants such as pines; cytokinin is a hormone and amino acids are used to make protein.
The movement of the whole organism to an external stimulus is termed
Answer: B (a taxis)
A taxis is the movement of a whole organism towards or away from a stimulus.
Which of the following vertebrae lacks a centrum?
Answer: A (Atlas)
The atlas is a ring of bone with no centrum; its centrum has joined the axis to form the odontoid process.
The function of the epididymis in mammals is the
Answer: B (storage of sperms)
The epididymis is a coiled tube beside the testis where sperms are stored and mature.
A collection of achenes formed from several carpels of a flower is
Answer: B (an aggregate fruit)
An aggregate fruit, such as the strawberry, forms from many free carpels of one flower.
Vegetative progagation is described as asexual reproduction because
Answer: D (there is no exchange of genetic materials)
No gametes fuse, so there is no mixing of genetic material; the new plants are identical to the parent.
Epigeal germination can be found in
Answer: D (groundnut)
In groundnut the cotyledons are lifted above the soil (epigeal); sorghum, maize and millet are cereals with hypogeal germination.
A dwarf plant can be stimulated to grow to normal height by the application of
Answer: B (gibberellin)
Gibberellins cause stem elongation, so they make dwarf plants grow tall.
The greatest contribution to genetic studies was made by
Answer: B (Gregor Mendel)
Gregor Mendel's pea experiments discovered the basic laws of inheritance; he is called the father of genetics.
The exchange of genes between homologous chromosomes is called
Answer: C (crossing-over)
During meiosis homologous chromosomes swap segments; this is crossing-over.
When two heterozygotes mate, the dominant trait will appear in
Answer: C (both the F1 and F2 generations)
Heterozygotes (Tt) crossed give 3 dominant : 1 recessive, and the dominant trait keeps showing in later generations too.
Which of the following characters is NOT sex-linked?
Answer: A (River blindness)
River blindness is an infection caused by a worm spread by blackflies, not an inherited trait.
The most important factors which influence an organism's way of life in its habitat are
Answer: C (temperature, water, light and predator-prey relationship)
An organism's way of life is shaped by physical factors (temperature, water, light) together with biotic ones such as predators and prey.
Organisms in an ecosystem are usually grouped according to their trophic level as
Answer: C (producers and consumers)
Trophic levels are feeding levels: producers make food, and consumers eat it.
Use the graph (number of organisms against time for communities I and II): The above diagram represents a competitive interaction between organisms in communities I and II. Which of the following statements is CORRECT?
Answer: B (II was wiped out from the environment at the end of the experiment)
Curve II rises, then falls to zero at the end, so II was eliminated by the competition; I rose and levelled off.
A food web is more stable than a food chain because
Answer: D (every organism has an alternative source)
In a food web each animal has more than one food source, so losing one source does not starve it.
Which of the following is likely to occur in a deciduous forest during the dry season?
Answer: D (The ground becomes bare)
Deciduous trees shed their leaves and the undergrowth dries up in the dry season, leaving the forest floor exposed.
Which of these is NOT an adaptive feature for arboreal life?
Answer: C (Possession of teeth)
A long tail helps balance, claws help grip bark and counter shading hides animals among branches, but teeth have nothing to do with living in trees.
Which of the following diseases can be prevented by inoculation?
Answer: C (Tuberculosis)
Tuberculosis can be prevented by the BCG vaccine; there is no routine vaccine for the others.
Sources of air pollutants are
Answer: C (sulphur mines, vehicle exhausts and aerosols)
All three in C release harmful gases or particles into the air; river dams and sewage are not air-pollution sources, and B lists pollutants, not sources.
Fertilizers are lost from the soil through
Answer: B (leaching, underground seepages and run-off)
Dissolved fertilizer is washed down by leaching and seepage or carried away by surface run-off.
Nitrogen-fixing micro-organisms in leguminous plants live symbiotically in the
Answer: A (root nodules)
Rhizobium bacteria live inside the swellings (nodules) on legume roots.