GCE O-Level · Science (Chemistry, Biology) (5088)

Inheritance: Practice Questions

5 multiple-choice questions marked as you go, and 5 written questions with worked solutions. All on Inheritance.

10 questions22 marksFree, no account

Question 1

1 mark

Which of the following describes an alternative form of a gene that occupies the same relative position on a pair of homologous chromosomes?

Question 2

1 mark

A cross is performed between two heterozygous tall pea plants (Tt). What is the expected phenotypic ratio of tall to short plants in the offspring?

Question 3

1 mark

A plant is homozygous for the dominant allele for tallness (T). If it is crossed with a short plant (tt), what is the expected phenotype of the \(F_{1}\) generation?

Question 4

1 mark

If a man with blood group O (genotype ii) and a woman who is homozygous for blood group A (genotype \(I^{A}I^{A}\)) have children, what is the probability that a child will have blood group A?

Question 5

1 mark

Which term describes the physical appearance or observable trait of an organism resulting from its genetic makeup?

Question 6

2 marks

State the sex chromosomes present in a normal human male body cell and state the sex chromosomes present in a normal human female body cell.

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Question 7

3 marks

In pea plants, the allele for tall stems (\(T\)) is dominant over the allele for short stems (\(t\)).
State the expected phenotypic ratio of the offspring resulting from a genetic cross between a heterozygous tall pea plant (\(Tt\)) and a short pea plant (\(tt\)).

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Question 8

5 marks

In a monohybrid cross between two heterozygous fruit flies with red eyes, the expected ratio of red-eyed to brown-eyed offspring is \(3:1\). However, when a scientist counts \(200\) actual offspring, the observed ratio is slightly different.
Explain why the observed ratio of phenotypes often differs from the expected theoretical ratio.

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Question 9

3 marks

Genetic variation and mutations contribute to the diversity and health of a population.

(a) Distinguish between continuous variation and discontinuous variation, providing one example of each.

(b) Define mutation and name one environmental factor that can increase the rate of mutation in human cells.

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Question 10

4 marks

In pea plants, the allele for tall height (T) is dominant over the allele for dwarf height (t).

(a) Define the terms phenotype and genotype.

(b) A heterozygous tall plant is crossed with a dwarf plant. Using a genetic diagram, predict the expected ratio of phenotypes in the offspring.

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