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Question 1 Report
(a) (i) Name four similarities found in plant and animal cells
(ii) In a tabular form list four different cells found in man and give a function for each of the cells.
(b) (i) Name the two types of cell divisions.
(ii) Give two examples each of life processes involved in each type of the cell division.
(c) Name the two types of reproduction usually associated with organisms.
(a)(i) Four similarities in plant and animal cells
(Any four.)
(a)(ii) Four cells found in man and their functions
| Cell | Function |
|---|---|
| Red blood cell (erythrocyte) | Transports oxygen (and some carbon dioxide) in the blood |
| White blood cell (leucocyte) | Defends the body against disease by destroying germs / producing antibodies |
| Nerve cell (neurone) | Transmits nerve impulses (messages) round the body |
| Sperm cell | Male reproductive cell that fertilises the egg |
| Muscle cell | Contracts and relaxes to bring about movement |
(Any four.)
(b)(i) Two types of cell division
Mitosis and meiosis.
(b)(ii) Two examples of life processes involving each
(c) Two types of reproduction in organisms
Asexual reproduction and sexual reproduction.
Answer Details
(a)(i) Four similarities in plant and animal cells
(Any four.)
(a)(ii) Four cells found in man and their functions
| Cell | Function |
|---|---|
| Red blood cell (erythrocyte) | Transports oxygen (and some carbon dioxide) in the blood |
| White blood cell (leucocyte) | Defends the body against disease by destroying germs / producing antibodies |
| Nerve cell (neurone) | Transmits nerve impulses (messages) round the body |
| Sperm cell | Male reproductive cell that fertilises the egg |
| Muscle cell | Contracts and relaxes to bring about movement |
(Any four.)
(b)(i) Two types of cell division
Mitosis and meiosis.
(b)(ii) Two examples of life processes involving each
(c) Two types of reproduction in organisms
Asexual reproduction and sexual reproduction.
Question 2 Report
(a) (i) What is Pollution?
(ii) Name two pollutants each of air and water.
(b) (i) State four effects of water pollution.
(ii)Mention four ways of preventing water pollution in an environment.
(c) (i) Name three sources of noise pollution.
(ii) State three effects of noise pollution on man.
(a)(i) Pollution
Pollution is the release of harmful or unwanted substances (pollutants) into the environment (air, water or soil), which makes it unclean, unsafe or unfit for living things.
(a)(ii) Two pollutants each
(b)(i) Four effects of water pollution
(b)(ii) Four ways of preventing water pollution
(c)(i) Three sources of noise pollution
Vehicles and aeroplanes (traffic), industries and factory machines, and loud music/loudspeakers (also generators, blasting/explosions, market noise).
(c)(ii) Three effects of noise pollution on man
Answer Details
(a)(i) Pollution
Pollution is the release of harmful or unwanted substances (pollutants) into the environment (air, water or soil), which makes it unclean, unsafe or unfit for living things.
(a)(ii) Two pollutants each
(b)(i) Four effects of water pollution
(b)(ii) Four ways of preventing water pollution
(c)(i) Three sources of noise pollution
Vehicles and aeroplanes (traffic), industries and factory machines, and loud music/loudspeakers (also generators, blasting/explosions, market noise).
(c)(ii) Three effects of noise pollution on man
Question 3 Report
State the principles involved in the following methods of food preservation:
(a) (i) Salting (ii) Refrigeration (iii) Drying (iv) Smoking (v) Chemicals.
(b) State four problems that may be caused by human overpopulation.
(c) Explain three ways by which the Government may increase food production.
(a) Principles of food preservation methods
(b) Four problems caused by human overpopulation
(c) Three ways the Government may increase food production
Answer Details
(a) Principles of food preservation methods
(b) Four problems caused by human overpopulation
(c) Three ways the Government may increase food production
Question 4 Report
(a) (i) Define the law of independent assortment.
(ii) State the findings from Mendel's experiment involving white-flowered and red-flowered pea plants.
(iii) Illustrate these findings by means of simple diagrams.
(b) Explain why blood groups A and B in man can exist both in heterozygous and homozygous conditions while blood group 0 can only exist in homozygous state. .
(a)(i) Law of independent assortment
Mendel's law of independent assortment states that when two or more pairs of contrasting characters (alleles) are considered together, each pair separates and is inherited independently of the other during the formation of gametes.
(a)(ii) Findings from the red-flowered and white-flowered pea cross
When a pure-breeding red-flowered pea plant was crossed with a pure-breeding white-flowered pea plant, all the offspring of the first filial generation (F1) were red-flowered. When these F1 plants were self-crossed, the second generation (F2) contained both red-flowered and white-flowered plants in the ratio of about 3 red : 1 white. This showed that red is dominant to white, and that the white character had only been hidden (masked) in the F1, reappearing in the F2.
(a)(iii) Illustration by diagrams
Let R = allele for red flower (dominant), r = allele for white flower (recessive).
Parents: RR (red) × rr (white)
Gametes: R and r
F1: all Rr (red-flowered)
F1 cross: Rr × Rr
| R | r | |
|---|---|---|
| R | RR (red) | Rr (red) |
| r | Rr (red) | rr (white) |
F2 ratio: 3 red : 1 white.
(b) Why A and B can be heterozygous or homozygous but O only homozygous
Blood groups in man are controlled by three alleles: IA and Ib, which are both dominant, and io, which is recessive. Because IA and Ib are dominant over io, group A can be produced by either IAIA (homozygous) or IAio (heterozygous), and group B can be produced by either IbIb (homozygous) or Ibio (heterozygous); in the heterozygous forms the dominant allele still expresses A or B and masks the recessive io. Group O, on the other hand, is caused only by the recessive allele io, which is expressed only when no dominant allele is present. Therefore group O can arise only from the homozygous recessive genotype ioio and cannot exist in a heterozygous state.
Answer Details
(a)(i) Law of independent assortment
Mendel's law of independent assortment states that when two or more pairs of contrasting characters (alleles) are considered together, each pair separates and is inherited independently of the other during the formation of gametes.
(a)(ii) Findings from the red-flowered and white-flowered pea cross
When a pure-breeding red-flowered pea plant was crossed with a pure-breeding white-flowered pea plant, all the offspring of the first filial generation (F1) were red-flowered. When these F1 plants were self-crossed, the second generation (F2) contained both red-flowered and white-flowered plants in the ratio of about 3 red : 1 white. This showed that red is dominant to white, and that the white character had only been hidden (masked) in the F1, reappearing in the F2.
(a)(iii) Illustration by diagrams
Let R = allele for red flower (dominant), r = allele for white flower (recessive).
Parents: RR (red) × rr (white)
Gametes: R and r
F1: all Rr (red-flowered)
F1 cross: Rr × Rr
| R | r | |
|---|---|---|
| R | RR (red) | Rr (red) |
| r | Rr (red) | rr (white) |
F2 ratio: 3 red : 1 white.
(b) Why A and B can be heterozygous or homozygous but O only homozygous
Blood groups in man are controlled by three alleles: IA and Ib, which are both dominant, and io, which is recessive. Because IA and Ib are dominant over io, group A can be produced by either IAIA (homozygous) or IAio (heterozygous), and group B can be produced by either IbIb (homozygous) or Ibio (heterozygous); in the heterozygous forms the dominant allele still expresses A or B and masks the recessive io. Group O, on the other hand, is caused only by the recessive allele io, which is expressed only when no dominant allele is present. Therefore group O can arise only from the homozygous recessive genotype ioio and cannot exist in a heterozygous state.
Question 5 Report
(a) (i) Define the term metamorphosis.
(ii) Name the two types of metamorphosis that organisms undergo and mention two organisms that undergo each type.
(b) (i) State four economic importance of insects and name an example of each of the insects involved.
(ii) List four peculiar features of social insects.
(a)(i) Metamorphosis
Metamorphosis is the series of changes in body form and structure that an animal undergoes from the egg (or young stage) to the adult stage.
(a)(ii) Two types of metamorphosis with organisms
(b)(i) Four economic importances of insects (with examples)
(Any four, each with an example.)
(b)(ii) Four peculiar features of social insects
Answer Details
(a)(i) Metamorphosis
Metamorphosis is the series of changes in body form and structure that an animal undergoes from the egg (or young stage) to the adult stage.
(a)(ii) Two types of metamorphosis with organisms
(b)(i) Four economic importances of insects (with examples)
(Any four, each with an example.)
(b)(ii) Four peculiar features of social insects
Question 6 Report
(a) (i) Define the term hydrosphere.
(ii) Give three examples of hydrosphere.
(b) (i) State the two laws of thermodynamics levels.
(c) (i) Name two local biotic communities in Nigeria and associate each type with a particular State in Nigeria.
(ii) List three factors that affect organisms in the marine habitat.
(iii) State three adaptive features of sea weeds.
(a)(i) Hydrosphere
The hydrosphere is the part of the earth that is made up of all the water bodies; that is, the total mass of water that covers the surface of the earth in liquid, solid or vapour form.
(a)(ii) Three examples of the hydrosphere
Oceans and seas, rivers and streams, and lakes (also ponds, springs, ground water, and ice caps/glaciers).
(b) The two laws of thermodynamics
(c)(i) Two local biotic communities in Nigeria (with a State)
(Other acceptable pairs: freshwater swamp – Bayelsa; derived savanna – Oyo.)
(c)(ii) Three factors affecting organisms in the marine habitat
(c)(iii) Three adaptive features of seaweeds
Answer Details
(a)(i) Hydrosphere
The hydrosphere is the part of the earth that is made up of all the water bodies; that is, the total mass of water that covers the surface of the earth in liquid, solid or vapour form.
(a)(ii) Three examples of the hydrosphere
Oceans and seas, rivers and streams, and lakes (also ponds, springs, ground water, and ice caps/glaciers).
(b) The two laws of thermodynamics
(c)(i) Two local biotic communities in Nigeria (with a State)
(Other acceptable pairs: freshwater swamp – Bayelsa; derived savanna – Oyo.)
(c)(ii) Three factors affecting organisms in the marine habitat
(c)(iii) Three adaptive features of seaweeds
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