JAMB Biology 2015

22 reviewed questions with answers and explanations.

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Question 2

An adaptation common in many submerged freshwater hydrophytes is

  1. waxy cuticle on shoot surface
  2. poor development of roots and xylem tissues
  3. well-developed roots and supporting system
  4. leaves reduced to spines
Answer and explanation

B: poor development of roots and xylem tissues

Many submerged aquatic plants have reduced roots and xylem because water is readily available and surrounding water supports their bodies. Hydrophyte anatomy varies with whether plants are submerged, floating or emergent.

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Question 4

The theory which supports the view that the large muscles developed by an athlete will be passed on to the offspring was proposed by

  1. Mendel
  2. Darwin
  3. Lamarck
  4. Pasteur
Answer and explanation

C: Lamarck

Lamarck’s historical proposal included inheritance of changes acquired during an individual’s life. In that account, increased use of muscles could enlarge them and the enlargement was proposed to pass to descendants.

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Question 5

The chromosomes of prokaryotes historically grouped as Monera lie in a nucleoid region within the

  1. nucleoplasm
  2. nucleus
  3. nucleolus
  4. cytoplasm
Answer and explanation

D: cytoplasm

Organisms historically grouped as Monera are prokaryotes, with chromosomes in a nucleoid region of the cytoplasm. They lack a membrane-bound nucleus and therefore do not contain nuclear nucleoplasm.

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Question 7

The pancreas secretes enzymes for the digestion of

  1. fats, proteins and carbohydrates
  2. fats, vitamins and cellulose
  3. fats, carbohydrates and vitamins
  4. proteins, cellulose and minerals
Answer and explanation

A: fats, proteins and carbohydrates

The pancreas releases enzymes that digest carbohydrates, proteins and fats in the small intestine. Vitamins and minerals generally do not need this kind of enzymatic breakdown.

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Question 8

The causative agent of bird flu is a

  1. protozoan
  2. virus
  3. bacterium
  4. fungus
Answer and explanation

B: virus

Bird flu is caused by avian influenza viruses. These infectious agents are viruses rather than bacteria, fungi or protozoa.

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Question 13

The process of shedding the exoskeleton of an arthropod is known as

  1. ecdysis
  2. instar formation
  3. metamorphosis
  4. osmosis
Answer and explanation

A: ecdysis

Ecdysis is shedding the old cuticle or exoskeleton. It allows an arthropod to expand before the new covering hardens.

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Question 14

Which listed dietary factor can contribute to constipation?

  1. lack of roughage
  2. vitamin B
  3. vitamin E
  4. lack of salts
Answer and explanation

A: lack of roughage

A diet low in fibre can contribute to constipation. Fibre helps stool retain bulk and water, although constipation has several possible causes.

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Question 15

In humans, the gland immediately above each kidney is the

  1. adrenal gland
  2. prostate gland
  3. pancreas
  4. thyroid gland
Answer and explanation

A: adrenal gland

An adrenal gland lies near the upper end of each kidney in humans. The pancreas, thyroid and prostate are in different anatomical locations.

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Question 16

Which analysis can compare a biological sample from an investigation with a person’s genetic profile?

  1. RNA analysis
  2. blood group test
  3. behavioural traits test
  4. DNA analysis
Answer and explanation

D: DNA analysis

DNA profiling compares variable DNA markers in biological samples. It can provide evidence about whose biological material is present, but does not by itself establish what happened or prove guilt.

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Question 17

An example of a fish that aestivates is

  1. croaker
  2. African lungfish
  3. shark
  4. cat fish
Answer and explanation

B: African lungfish

African lungfish can aestivate when their aquatic habitat dries, reducing activity and surviving within a protective cocoon. They use air breathing during this dormant period.

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Question 18

Changes in guard-cell turgor during stomatal opening and closing involve water movement by

  1. respiration
  2. osmosis
  3. diffusion
  4. transpiration
Answer and explanation

B: osmosis

Osmotic movement of water changes guard-cell turgor and helps open or close a stoma. Ion transport and signalling regulate these water movements.

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Question 19

Which of the following is common to the mosquito, housefly and blackfly?

  1. they are parasites of man
  2. their immature stages are aquatic
  3. they undergo complete metamorphosis
  4. their adults have two pairs of wings
Answer and explanation

C: they undergo complete metamorphosis

Mosquitoes, houseflies and blackflies develop through egg, larva, pupa and adult stages. This sequence is complete metamorphosis.

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Question 20

Which structures help a giant African rat detect nearby tunnel walls by touch?

  1. nostrils
  2. eyes
  3. vibrissae
  4. tails
Answer and explanation

C: vibrissae

Vibrissae are sensitive whiskers that detect nearby surfaces through touch. They help a rat assess spaces and obstacles in dark or confined surroundings.

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Question 22

The plant compounds used in vegetable tanning of hides are

  1. alkaloid
  2. resin
  3. tannin
  4. gum
Answer and explanation

C: tannin

Tannins bind proteins and are used in vegetable tanning to convert hides into leather. They are plant secondary compounds with biological functions, not merely useless waste.

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Question 25

The photosynthetic pigments include

  1. chloroplast and cytochromes
  2. melanin and haemoglobin
  3. chlorophyll and carotenoids
  4. carotenoids and haemoglobin
Answer and explanation

C: chlorophyll and carotenoids

Chlorophylls and carotenoids absorb light in photosynthetic systems. Carotenoids can also protect against light-related damage, while chlorophyll participates centrally in light capture.

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Question 26

The highest level of ecological organization is the

  1. ecosystem
  2. niche
  3. biosphere
  4. population
Answer and explanation

C: biosphere

The biosphere includes all ecosystems and regions supporting life on Earth. It is therefore broader than a single ecosystem or population.

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Question 28

The eye defect that rises because the cornea is not curved smoothly is

  1. astigmatism
  2. short-sightedness
  3. long-sightedness
  4. presbyopia
Answer and explanation

A: astigmatism

Astigmatism can result from uneven curvature of the cornea or lens, causing light to focus differently in different directions. This can blur or distort vision.

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Question 29

Which of the following is an example of parasitism?

  1. a squirrel living in an abandoned nest of a bird
  2. mistletoe growing on an orange tree
  3. fungi growing on a dead tree branch
  4. cattle egrets taking ticks from the body of cattle
Answer and explanation

B: mistletoe growing on an orange tree

Mistletoe obtains water and mineral resources from its living host and can reduce the host’s resources. This is parasitism, even though mistletoe can also photosynthesise.

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Question 31

Which listed event can increase competition by reducing available water?

  1. emigration
  2. drought
  3. mortality
  4. dispersion
Answer and explanation

B: drought

Drought can reduce water and food availability, increasing competition for the remaining resources. Its effect depends on the population and habitat.

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Question 33

Which organelle carries out oxidative phosphorylation in a typical plant cell?

  1. nucleus
  2. nucleolus
  3. endoplasmic reticulum
  4. mitochondrion
Answer and explanation

D: mitochondrion

Mitochondria carry out the citric-acid cycle and oxidative phosphorylation in eukaryotic cells. Glycolysis occurs in the cytosol, so respiration is not confined entirely to mitochondria.

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Question 35

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The process illustrated is

  1. gametogenesis
  2. sexual reproduction in Rhizopus
  3. sexual reproduction in Spirogyra
  4. sporulation

Question 36

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The structure labelled I is the

  1. zygospore
  2. conidiophore
  3. sporangium
  4. hypha

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