All 60 questions from the Joint Admissions and Matriculation Board (JAMB) Biology 2011 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.
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The branch of Biology that deals with the principles of classification of organisms is known as
The branch of biology that deals with the principles of classification of organisms is known as taxonomy.
Which of the following structures is a tissue?
Blood contains many cells such as red blood cells (erythrocytes), white blood cells (leucocytes) and blood platelets (thrombocytes), so it is classed as a tissue.
Which of the following cells are not regarded as specialized cells?
Sperm cells, root tip cells and muscle cells are all specialized cells. The term 'somatic cell' is too ambiguous to be considered specialized.
Which of the following pairs of cells carry out the same function?
Spermatozoon and ovum perform the same function i.e. they are both used for reproduction.
If Amoeba is placed in a salt solution, the contractile vacuoles would
The contractile vacuole removes excess water from the protozoan's body. In salt solution the organism loses water instead of gaining it, so the vacuole forms less frequently.
In which of the following habitats is Paramecium not found?
Paramecium is found in pond, lake, puddle etc., not typically in an aquarium.
The following processes are involved in water movement in the endodermis except
Osmosis, diffusion and active transport all play a part in water movement in the endodermis; 'vacuolar pathway' is not a recognised term here.
Cells that utilize a lot of energy are characterized by the presence of a large number of
Mitochondria are the powerhouse of the cell, so cells needing lots of energy have many mitochondria.
The part labeled II in the diagram is the
The part labeled 'II' is the chromatid; a chromosome comprises two chromatids.
The part labelled I is called the
The part labeled 'I' is the spindle.
Secondary growth is brought about by the activities of the
In gymnosperms and most dicots, secondary growth (increase in diameter) results from activity of the vascular cambium and cork cambium (phellogen).
A monocot root is different from a dicot root by having
A monocot root has a wide pith while a dicot root does not.
Which of the following statements best describes haemoglobin? It is
Haemoglobin is the pigment in red blood cells responsible for transporting oxygen.
Inhaled air is made warm and moist in the
Inhaled air is warmed and moistened as it passes through the paranasal sinuses surrounding the nasal cavity.
Which of the following structures is not involved in respiration?
The stomach is not adapted for respiration; lung books (arachnids), mouth (amphibian buccal respiration) and trachea (insects) are respiratory structures.
Filtrate in the Bowman's capsule contains vitamins because
Vitamins appear in the filtrate mainly because most of them are fat soluble.
More sweat is produced during muscular exercise because
Sweating is an adaptation to lower body temperature, which rises during exercise; sweat cools the body as it evaporates.
Which of the following neurons may not have myelin sheath?
The myelin sheath insulates axons and speeds impulse conduction. Intermediate (association) neurons are typically unmyelinated.
Which of the following is an effector organ?
Skin is regarded as an effector organ since it can react to impulses from the brain.
During sexual reproduction in Paramecium, how many times does the zygote divide to produce eight nuclei?
Reproduction in Paramecium is by conjugation; the zygote in each conjugant divides three times to form eight nuclei.
The testes in male mammals descend into the scrotal sac because
The testes must be at a temperature slightly lower than body temperature for optimum sperm production.
Some animals return to water bodies to reproduce because
The land temperature may not be suitable for the development of their embryos, so they return to water to reproduce.
Which of the following methods is appropriate for the cultivation of cassava?
Cassava is propagated by stem cutting.
What will be the chromosome number of the hybrid of two varieties of a plant with 36 chromosomes in the endosperm cell?
Endosperm cells are triploid (3n). If 3n = 36, then 2n = 36/3 x 2 = 24.
Kreb's cycle occurs in the
Glycolysis occurs in the cytoplasm, while the Krebs (citric acid) cycle occurs in the mitochondria.
The process whereby electrons are emitted from chlorophyll and returned to it unchanged is known as
In cyclic photophosphorylation, electrons emitted from P700 cycle through the electron transport chain and return to the same photosystem; NADPH and oxygen are not produced.
Which of the following statements about photosynthesis is not true?
Photosynthesis always results in an increase in dry weight of the plant, so statement A is false.
The equation below represents the process of glycolysis: Glucose+ATP → X+ADP. X in the equation represents
Glucose is phosphorylated by addition of a phosphate group to form glucose phosphate.
The removal of all phloem tissues of the stem of a plant close to the root system for a long period of time is likely to
Removing all phloem tissue for a long time will kill the plant because conduction of food to the roots is stopped (ring-barking).
The conversion of glucose to starch in the leaf during the day principally
Plants store carbohydrate as starch (animals and fungi store it as glycogen); converting glucose to starch allows storage for later use.
Which of the following groups of substances are not six-carbon compounds?
Pyruvate is not a carbohydrate; it is formed when a six-carbon glucose molecule is broken down into three-carbon molecules.
A purple colour was obtained when sodium hydroxide solution and a drop of copper sulphate solution was added to a food substance. The food substance is likely to be a
This is the Biuret test, which gives a purple/violet colour in the presence of protein.
Which of the following enzymes is active in the duodenum?
Trypsin is produced in the pancreas but transported (with other enzymes in pancreatic juice) to the duodenum where it converts peptone to polypeptides.
The following organisms are producers except
Hibiscus, cactus and spirogyra all contain chlorophyll and are producers; mushrooms are achlorophyllous (fungi) and are not producers.
Which of the following structures produces the greatest variety of digestive enzymes?
The pancreas produces the greatest variety of digestive enzymes: amylase (amylopsin), lipase, trypsin, chymotrypsin, carboxypeptidase, ribonuclease and deoxyribonuclease.
The following are abiotic components of an ecosystem except
Abiotic components are non-living; bacteria are living organisms and so are biotic, not abiotic.
[Capture-recapture data: First capture = 200, second capture = 120; Number of organisms with mark in second capture = 40] The total number of organisms therefore is
N = (first capture x second capture) / marked recaptures = (200 x 120) / 40 = 600.
Ecological investigation in a habitat includes the following procedures except
Investigating the genetic make-up of specimens is not part of ecological investigation, which studies interactions of organisms with each other and their environment.
Which of the following substances when lost from the body of a mammal will not be returned to the ecosystem?
Sweat, urea and carbon dioxide are returned to the ecosystem; heat energy dissipates and is not returned/recycled in the ecosystem.
The rate of decomposition of organisms is faster in the tropical rain forest than in other biomes because
Tropical rainforests receive abundant rainfall (2000-4000mm annually) and have high temperatures/humidity, which speed up decomposition.
A Xerophyte conserves water by possession of the following features except
Xerophytes have thick cuticle, sunken stomata and fleshy stems to conserve water; broad leaves increase water loss through transpiration, so this is the exception.
The falling off of leaves of deciduous trees is helpful to the plant because it
Shedding leaves reduces the surface area for transpiration, helping the plant conserve water.
A sample of wet garden soil of known weight was heated to constant weight. The loss of weight is due to loss of
Continual heating causes loss of water first; if heating persists to a constant weight, the organic matter (humus) is also burnt off.
Assuming that a period of stable population size is followed by a period when natality increases by ten (10) percent and immigration by twenty (20) percent of population size, the population size will
An increase in natality (birth rate) and immigration rate causes the population to begin to increase.
Which of the following methods does not make water fit for drinking?
Alum coagulates solid impurities in water (the water must still be boiled to kill bacteria); it does not by itself make water fit for drinking.
Vaccination results in
Vaccination works by stimulating the body to produce antibodies against the antigen introduced.
Leguminous crops are incorporated into crop rotation in order to
Leguminous crops host nitrogen-fixing bacteria (e.g. Rhizobium leguminosarium) in their root nodules, enriching the soil with nitrogen.
Which of the following practices improves crop yield in a clayey soil? Addition of
Adding lime and humus improves crop yield in clayey soil.
Which of the following activities promotes forest conservation?
Afforestation (planting trees) promotes forest conservation, while the other options tend to encourage deforestation.
Which of the following statements is not true about continuous variation? It
Continuous variation is usually controlled by many genes (polygenic), not just one or two gene pairs.
Acquired characters are
Acquired characters are caused by the environment; they cannot be passed from one generation to the next.
Differences in the characteristics observed between individuals of the same species is known as
Variation refers to the difference in characteristics observed between individuals of the same species.
Which of the following statements best describes protein synthesis?
During translation, the ribosome moves (translocates) along the mRNA, exposing a new codon each time for base pairing.
If a person has two alleles of the sickle cell anaemia gene, the person is
A person with two alleles of the sickle cell gene (homozygous) is a sufferer of the disease; a person with just one allele is a carrier.
What is the probability of a man of blood group AB married to a woman of blood group O producing a child of blood group O?
It is not possible for a man of blood group AB married to a woman of blood group O to produce a child of blood group O; the child will be either A or B.
A man with blood group IA IA is married to a woman with blood group IA IO. The blood group of their son is likely to be
Since allele A is dominant over O, the child of this cross can only be blood group A.
Natural selection is a consequence of
Natural selection is a consequence of adverse conditions, which cause organisms to strive and compete for survival.
Which of the following components of Lamarck's theory of evolution is considered faulty?
The loophole in Lamarck's theory of use and disuse is the claim that acquired traits are transmittable to offspring, which is false.
A vestigial structure in humans is
Vestigial organs have no popular function in humans; the tail bone (caudal vertebrae) is a classic example, alongside the appendix.
Adenine pairs with thymine because
Guanine and adenine are purines; cytosine and thymine are pyrimidines. A purine always pairs with a pyrimidine (adenine-thymine, guanine-cytosine).
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