6.1 Reproduction

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Question 27

In guinea pigs, fur texture is controlled by a single gene. A dominant allele, $R$ , codes for a rough coat, while a recessive allele, $r$ , codes for a smooth coat.

Which of the following is the correct definition of a recessive allele?

A. An allele that is only expressed in the phenotype when a dominant allele is absent.
B. An allele that is always expressed in the phenotype when at least one copy is present.
C. An allele that is only inherited on the sex chromosomes.
D. An allele that prevents a dominant allele from being transcribed.

[1]

Two guinea pigs that are both heterozygous for a rough coat ( $R r$ ) are mated. Determine the probability that an offspring from this cross will have a smooth coat.

[2]

Calculate the probability that their next offspring will be a female with a smooth coat. Use the relation:

\text{probability of a female with a smooth coat} = \text{probability of smooth coat} \times \text{probability of being female}

[3]

6.1 Reproduction

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Question 27

In guinea pigs, fur texture is controlled by a single gene. A dominant allele, $R$ , codes for a rough coat, while a recessive allele, $r$ , codes for a smooth coat.

Which of the following is the correct definition of a recessive allele?

A. An allele that is only expressed in the phenotype when a dominant allele is absent.
B. An allele that is always expressed in the phenotype when at least one copy is present.
C. An allele that is only inherited on the sex chromosomes.
D. An allele that prevents a dominant allele from being transcribed.

[1]

Two guinea pigs that are both heterozygous for a rough coat ( $R r$ ) are mated. Determine the probability that an offspring from this cross will have a smooth coat.

[2]

Calculate the probability that their next offspring will be a female with a smooth coat. Use the relation:

\text{probability of a female with a smooth coat} = \text{probability of smooth coat} \times \text{probability of being female}

[3]

6.1 Reproduction

Question 27

Markscheme

6.1 Reproduction

Question 27

Markscheme

6.1 Reproduction

Question 27

6.1 Reproduction Questions

6.1 Reproduction

Question 27

6.1 Reproduction Questions