Question 1

Scientists self-pollinated some pea plants that were heterozygous for the gene controlling height. They expected a 3 : 1 ratio of tall plants to short plants in the offspring.

1,046 plants grew in the next generation. 798 were tall and 248 were short.

What is a statistical test that could be used to determine if these numbers are significantly different from a 3 : 1 ratio?

  A  

chi-squared


  B  

Spearman’s rank

  C  

standard deviation


  D  

student’s t-test


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Question 2

A researcher carried out an investigation into patterns of inheritance using mice as a model organism and observed the coat colour of the mice.

• Coat colour is controlled by two alleles which are not sex linked.

• The allele for yellow coat colour (A) is dominant to the allele for normal (agouti) coat colour (a).

Heterozygous yellow mice were crossed with each other repeatedly and the offspring obtained are shown in the table below.

Which statement describes the correct way to analyse these results?

  A  

use a student's t-test with an expected ratio of 2 : 1 yellow to normal mice

  B  

use a 𝛘2 test with an expected ratio of 2 : 1 yellow to normal mice

  C  

use a student's t-test with an expected ratio of 3 : 1 yellow to normal mice

  D  

use a 𝛘2 test with an expected ratio of 3 : 1 yellow to normal mice

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Question 3

A couple have a child. Both parents are heterozygous for the cystic fibrosis allele.

What is the probability that the child will have cystic fibrosis?

  A  

0.25

  B  

0.5

  C  

0.75

  D  

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Question 4

In a genetic context, what is a carrier?

  A  

an individual heterozygous for a recessive allele but not expressing it

  B  

an individual showing a dominant phenotype

  C  

an individual homozygous for a recessive allele

  D  

an individual with multiple alleles for a trait

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Question 5

What does a chi-squared value higher than the critical value suggest about the null hypothesis?

  A  

it should be confirmed

  B  

it cannot be accepted or rejected

  C  

it should be rejected

  D  

it is strongly supported

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Question 6

What does an epistatic gene do?

  A  

has no effect on other genes

  B  

is always recessive

  C  

is always dominant

  D  

masks the expression of other genes

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Question 7

Which term describes a characteristic that is determined by a gene located on a sex chromosome?

  A  

autosomal

  B  

sex-influenced

  C  

sex-limited

  D  

sex-linked

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Question 8

What kind of genetic cross examines the inheritance of two different genes?

  A  

multiple allele cross

  B  

monohybrid cross

  C  

dihybrid cross

  D  

trihybrid cross

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Question 9

What is the probability of a child having blood group AB if both parents are heterozygous blood group A (IAIO) and B (IBIO)?

  A  

25%

  B  

50%

  C  

75%

  D  

100%

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Question 10

In human blood groups, which alleles are codominant?

  A  

IA and IO

  B  

IA and IB

  C  

IB and IO

  D  

IO is codominant with both IA and IB

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Question 11

What term describes alleles that are both expressed in the phenotype?

  A  

recessive

  B  

dominant

  C  

incomplete dominant

  D  

codominant

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Question 12

In a dihybrid cross, what is the phenotypic ratio for a cross between individuals both heterozygous for two genes (e.g., RrYy x RrYy)?

  A  

1 : 1 : 1 : 1

  B  

9 : 3 : 3 : 1

  C  

3 : 1

  D  

1 : 2 : 1

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Question 13

What is the expected phenotypic ratio in the F2 generation of a monohybrid cross between a homozygous dominant and a homozygous recessive individual?

  A  

1 : 1

  B  

2 : 1 : 1

  C  

3 : 1

  D  

9 : 3 : 3 : 1

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