Question 5
(a) List threemajor photic zones of a marine habitat. [3 marks]
(b) (i) What is population? [2 marks]
(ii) Name two instruments used in the study of insect populations. [2 marks]
(c) Name four methods of preserving fish from decaying. [4 marks]
(d) (i) What is tropism? [2 marks]
(ii) Name two other types of responses which plants showin reaction
to changes in their environment. [2 marks]
(e) (i) What is a fingerprint? [2 marks]
(ii) List three types of fingerprints. [3 marks]
(f) State two factors to be considered before carrying out a blood transfusion. [2 marks]
(g) In rats, the allele T for long tail is dominant while the allele t for short tail
is recessive. State:
(i) two possible genotypes of a rat with long tail. [2 marks]
(ii) one possible genotype of a rat with short tail. [1 marks]
(h) Two pea plants heterozygous for rough seeds were crossed. What is the expected:
(i) phenotypic ratios;
(ii) genotypic ratios of the offspring? [5 marks]
Observation
This question was compulsory.
In (a),some candidates could not list the three major photic zones in a marine habitat.
In (b), a few candidates could define population correctly but could not spell the instruments used in the study of insect populations.
In (c), Some candidates could name methods of preserving fish from decaying but lost marks to poor spellings.
In (d), many candidates could define tropism and name other types of responses which plants show in reaction to changes in their environment but lost marks to the spelling of technical terms.
In (e), candidates were able to give examples of fingerprints but could not define fingerprint.
In (f),some candidates could statefactors to be considered before carrying out a blood transfusion.
In (g),some candidates were able to state possible genotypes of a rat with long tail and give the possible genotype of a rat with short tail.
In (h),some candidates could state the phenotypic ratiosgenotypic ratios of the offspring from the crossing of two pea plants heterozygous for rough seeds.
The expected answers are:
(a) Major Photic Zones of a Marine Habitat
- Epipelagic zone
- Mesopelagic zone
- Bathypelagic zone [3 marks]
(b) (i) Population
Total number of organisms; of the same species; living in a particular habitat/area; at a
particular time.
Any 2x1[2marks]
(ii) Instruments used in Study of Insect Population
- pooter/aspirator;
- sweep net;
- pitfall trap;
- butterfly net.
Any 2x1[2marks]
(c) Methods of Preserving fish from Decaying
- freezing; canning; drying; salting; smoking;
Any 4x1[4marks]
(d)(i) Tropism
A directional growth movement made by a part of a plant; in response to external
stimulus.
2x1[2marks]
(ii) Types of Response
Taxism; nastism.
2x1[2marks]
(e)(i) Fingerprints
These are pattern; formed by the ridges in the dermis of the skin on the finger tips; each
individual has a unique pattern of fingerprints.
Any 2x1[2marks]
(ii) Types of Fingerprints
Loop; whorl/plain whorl compound; tented arch; accidental; double whorl/double loop.
Any 3x1[3marks]
(g)(i) Possible Genotype of Rat with Long Tail
TT; Tt
2x1[2marks]
(ii) Possible Genotype of Rat with Long Tail
1x1[1mark]
(h)(i) Phenotypic ratios
3 round seeds one smooth seeds/3:1
1x1[1mark]
(ii) Genotypic ratios
1:2:1