HARD
AS and A Level
IMPORTANT
Earn 100

Construct a genetic diagram to predict the ratio of phenotypes in the F2 generation of a cross between a homozygous brown rabbit and a white rabbit.

Important Questions on Inheritance

HARD
AS and A Level
IMPORTANT
Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 16 - Inheritance>Question>Q 11
A test cross was carried out between a brown rabbit and a white rabbit. Five brown offspring and one white offspring were produced. Use a genetic diagram to show how this indicates that the brown rabbit must be heterozygous.
HARD
AS and A Level
IMPORTANT
Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 16 - Inheritance>Question>Q 11
A test cross using a different brown rabbit produced four offspring, all of which were brown. Explain why this indicates that the brown rabbit may be homozygous.
HARD
AS and A Level
IMPORTANT
Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 16 - Inheritance>Questions>Q 12
Explain why a boy cannot inherit haemophilia from his father.
HARD
AS and A Level
IMPORTANT
Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 16 - Inheritance>Questions>Q 16

In a species of plant, the alleles for the tall stem is dominant to short. The two alleles for leaf colour, giving green or white in the homozygous condition are codominant, producing variegated leaves in the heterozygote.

A plant with tall stems and green leaves was crossed with a plant with short stems and variegated leaves. The offspring from this cross consisted of plants with tall stems and green leaves and plants with tall stems and variegated leaves with a ratio of 1 :1. Construct a genetic diagram to explain this cross.

HARD
AS and A Level
IMPORTANT
Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 16 - Inheritance>Questions>Q 20
What ratio of phenotypes would you expect from the cross of a male Drosophila from the F1 generation discussed with a female with ebony body and aristapedia antennae if the genes for body colour and antennae shape were not linked- that is, they were on different chromosomes? Explain using a genetic diagram.
HARD
AS and A Level
IMPORTANT
Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 16 - Inheritance>Question>Q 23

Using the symbols G and g for the alleles for coat colour and D and d for the alleles for eye colour. A cross between the animals in the F1 generation (DdGg X DdGg) gives 9 : 3: 3 : 1 ratio. In the actual cross between the animals in the generation, the numbers of each phenotype obtained in the offspring were:

grey body, dark eyes  - 54

grey body, pale eyes   - 4

white body, dark eyes   - 4

white body, pale eyes  - 18

Use a chi-square test to determine whether the difference between these observed results is significant.

HARD
AS and A Level
IMPORTANT
Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 16 - Inheritance>EXAM-STYLE QUESTIONS>Q 1
Distinguish between the terms genotype and phenotype.
HARD
AS and A Level
IMPORTANT
Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 16 - Inheritance>EXAM-STYLE QUESTIONS>Q 1
Distinguish between the terms homozygous and heterozygous.