48 questions. Try each one, then open the answer to check yourself and read the explanation.
The function of ribosomes in cells is
Answer: A (protein synthesis)
Ribosomes are the sites where amino acids are joined together to make proteins.
Which of the following structures is common to Euglena, white blood cell and Amoeba?
Answer: D (Cell membrane)
Every living cell is bounded by a cell membrane. None of these three has a cell wall, and none has cilia.
The term 'Thallophyta' refers to
Answer: B (algae and fungi)
Thallophytes have a simple body (thallus) not divided into true roots, stems and leaves; the group is made up of algae and fungi.
The following organisms are hermaphrodites EXCEPT
Answer: C (Schistosoma)
Schistosoma (the blood fluke) has separate male and female worms, unlike most flatworms. Snails, tapeworms and earthworms carry both sex organs.
Parasitic forms are NOT found among
Answer: C (molluscs)
Flatworms (tapeworm, liver fluke), roundworms (Ascaris) and annelids (leeches) all include parasites, but molluscs are free-living.
Which of the following sets of organisms represents the correct trend from simple to complex structural organization? 1 Mollusca 2 Platyhelminthes 3 Nematoda 4 Protozoa
Answer: D (4 → 2 → 3 → 1)
Protozoa are single-celled, flatworms have three cell layers but no body cavity, roundworms have a simple body cavity, and molluscs have organ systems and a true coelom.
Spirogyra, Euglena and Chlamydomonas share many characteristics EXCEPT
Answer: C (mobility)
All three photosynthesise and respond to stimuli, but Spirogyra is a filament that cannot swim, while Euglena and Chlamydomonas move with flagella.
The prothallus of a fern is equivalent to the gametophyte generation of a moss because it
Answer: C (bears sexual organs)
The gametophyte is the generation that carries the sex organs (antheridia and archegonia), and in ferns these are found on the prothallus.
What is the function of trichocyst in Paramecium?
Answer: B (Defence)
Trichocysts are tiny threads that Paramecium shoots out when disturbed, to defend itself and to anchor itself.
Use the diagram (life cycle of tapeworm) to answer: At which stage in this cycle can man be infected?
Answer: B (4)
Man is infected by eating undercooked pork containing the bladder worm (cysticercus), the stage labelled 4.
Use the diagram (life cycle of tapeworm) to answer: Which stage is found in the muscle of an infected pig?
Answer: B (4)
The six-hooked embryo (3) bores out of the pig's gut and settles in the muscle, where it becomes the bladder worm (4); so stage 4 is what is found in the muscle.
The long and coiled intestine of a young tadpole is an adaptation to its
Answer: A (herbivorous diet)
Young tadpoles feed on plant material, which is slow to digest, so they need a long gut.
Lung books are used for respiration in
Answer: A (spiders)
Spiders and scorpions breathe with lung books; insects and millipedes use tracheae.
Insects and millipedes have many features in common EXCEPT
Answer: C (compound eyes)
Both are arthropods with an exoskeleton, jointed legs and a segmented body, but millipedes have only simple eyes (ocelli), not compound eyes.
The major function of the swim-bladder in fishes is
Answer: B (buoyancy)
The swim-bladder is a gas-filled sac that the fish adjusts so it can float at any depth without effort.
Which of the following statements gives the BEST description of bark?
Answer: A (Tissues outside the vascular cambium)
Bark is everything outside the vascular cambium: secondary phloem, cortex and the cork layers.
In the transverse section of the leaf of maize vascular bundles are arranged in
Answer: A (a row)
A maize leaf has parallel veins, so in a cross-section the vascular bundles lie side by side in a single row.
If an animal has diastema, it would NOT possess
Answer: B (cannines)
A diastema is the gap in the jaw of herbivores such as rabbits and goats where canine teeth would be.
If the gall bladder of a mammal is damaged, which of the following will be most seriously affected?
Answer: C (Digestion of fats and oils)
The gall bladder stores bile, which emulsifies fats so that lipase can digest them.
Which of the following will be first digested if ingested at the same time?
Answer: B (Cooked rice)
Rice is mostly starch, and starch digestion starts in the mouth with salivary amylase; protein and fat digestion start later in the gut.
If the phloem of a healthy plant is killed by heat treatment the
Answer: B (food manufacture in the leaves will accumulate)
Phloem carries food made in the leaves to the rest of the plant; if it is killed, the food stays and builds up in the leaves.
In the mammalian respiratory system, exchange of gases occurs in the
Answer: D (alveoli)
The alveoli have thin, moist walls surrounded by capillaries, which is where oxygen and carbon dioxide are exchanged.
In the kidney, the malpighian corpuscle is located in the
Answer: C (cortex)
The Malpighian corpuscle (glomerulus with Bowman's capsule) lies in the outer region, the cortex.
The skin, through the sweat glands, functions as
Answer: A (an excretory organ)
Sweat glands remove water, salts and a little urea from the body, so the skin acts as an excretory organ.
Parenchyma cells serve as supporting tissue when they
Answer: D (become turgid)
When parenchyma cells are full of water (turgid) they press against each other and hold soft parts of the plant firm.
Taxism differs from tropism because
Answer: A (the whole organism is affected)
In a taxis the whole organism moves towards or away from a stimulus; in a tropism only part of a plant grows towards or away from it.
A dry dehiscent fruit which breaks up into one-seeded parts is a
Answer: A (schizocarp)
A schizocarp splits into one-seeded pieces called mericarps, as in Desmodium.
Airspaces are characteristic of seeds or fruits dispersed by
Answer: B (water)
Air spaces make fruits like the coconut light enough to float, so they are carried by water.
In vegetation propagation, which of the following requires part of another plant to develop?
Answer: A (Scion)
A scion is a shoot that is grafted onto the stock (rooted part) of another plant, so it cannot grow on its own.
Which of these plant groups are normally propagated by asexual means?
Answer: A (Banana, yam, pineapple and cassava)
Banana (suckers), yam (tubers), pineapple (crowns/suckers) and cassava (stem cuttings) are all grown from vegetative parts; rubber, orange, cashew and coffee are usually raised from seed or budding.
In a mammal, the placenta performs functions similar to those to the
Answer: A (lungs kidneys and digestive system)
Through the placenta the foetus gets oxygen (like lungs), gets rid of wastes (like kidneys) and receives digested food (like the gut).
The radicle of a bean seedling grows most rapidly in the region
Answer: B (just above the root tip)
The region of elongation lies just behind (above) the root tip, where newly formed cells grow longer.
The main function of the choroid is
Answer: C (supply of nutrients to tissues of the eye)
The choroid is full of blood vessels that nourish the eye; its dark pigment also stops reflection.
What part of the central nervous system is concerned with answering an examination question
Answer: A (Cerebrum)
Thinking, memory and reasoning are controlled by the cerebrum.
If a dark-skinned woman (Bb) marries an albino man (bb) and they have four children, how many of the children will be dark-skinned?
Answer: B (2)
Bb × bb gives Bb and bb in equal numbers, so half of four children, 2, are expected to be dark-skinned.
A red-coloured flower when crossed with a white-coloured one produced pink flowers. This is an example of
Answer: B (blending inheritance)
Neither colour is dominant, so the offspring show a mix of both (pink); this is called incomplete dominance or blending.
The turbidity of a pond can be measured using the
Answer: B (secchi disc)
A Secchi disc is lowered into the water until it disappears; the depth shows how cloudy (turbid) the water is.
If an organism obtains its food by means of haustoria, it is said to be
Answer: D (parasitic)
Haustoria are special roots that a parasitic plant like dodder pushes into its host to suck out food.
Which of the following relationships involves only one organism?
Answer: A (Saprophytism)
A saprophyte feeds on dead matter on its own; the other relationships all involve two living organisms.
Which of the following has the greatest influence on the distribution of animals in marine and fresh water habitats?
Answer: B (Salinity)
The main difference between sea water and fresh water is salt content, and most animals can only live within a narrow salinity range.
Which of these groups of animals is likely to be found in fresh water?
Answer: B (Blood worm, pond skater and dragonfly larva)
Blood worms, pond skaters and dragonfly nymphs all live in ponds; scorpions and ant-lions live on land.
One of the characteristics of plants in the savanna is the
Answer: D (possession of thick, flaky barks)
Savanna trees have thick, corky bark that protects them from bush fires and dry weather.
Which of the following diseases can be contracted in areas with fast flowing rivers?
Answer: D (Onchocerciasis)
Onchocerciasis (river blindness) is spread by the blackfly Simulium, which breeds in fast-flowing rivers.
Which of the following causes pollution?
Answer: D (Burning of refuse)
Burning refuse releases smoke, soot and poisonous gases into the air.
The mineral nutrient that is most bound to the soil is
Answer: A (phosphorus)
Phosphate ions combine tightly with soil particles and with iron, aluminium and calcium, so phosphorus barely moves in soil.
The mineral nutrient that easily gets leached out of the soil is
Answer: D (nitrate)
Nitrate ions are very soluble and are not held by soil particles, so rain washes them down easily.
Most commercial fertilizers are rich in salts of
Answer: B (nitrogen, phosphorus and potassium)
Common fertilizers are NPK fertilizers, supplying nitrogen, phosphorus and potassium.
Dead plants and animals are decomposed by bacteria and fungi into
Answer: D (ammonia)
Decomposers break down proteins in dead bodies and release ammonia (ammonification); nitrifying bacteria later change it to nitrites and nitrates.