Year 9 - Genetics

These two sisters are identical twins. The reason why they look alike is because they have

These two sisters are identical twins. The sisters found out that all their features were controlled by

These two sisters are identical twins. The sisters have a brother with cystic fibrosis.
This meant he often had

These two sisters are identical twins. The sisters have a brother with cystic fibrosis. Their brother decided that he would not have any children of his own because the probability of him passing on the allele for cystic fibrosis was

Our body is made up of different cells.
Each cell contains structures that help to keep the cell alive.
Part X on the diagram shows a unit of inheritance.
A unit of inheritance is

Chromosomes are found in the part of the cell labelled Z.
What is Z?

How many chromosomes are found in Z?

The diagram shows the inheritance of eye colour in a family. The allele for brown eyes is dominant (B) and the allele for blue eyes is recessive (b).
Which of the following statements is true?

The diagram below shows the inheritance of eye colour in a family. The allele for brown eyes is dominant (B) and the allele for blue eyes is recessive (b).
What is the sex and eye colour of baby M?

The diagram below shows the inheritance of eye colour in a family. The allele for brown eyes is dominant (B) and the allele for blue eyes is recessive (b).
In the family shown, Rachel has an identical twin. Rachel has brown eyes.
Who is Rachel’s identical twin?

Cystic fibrosis is an inherited disease where certain cells produce abnormal mucus.
The allele for the disease is recessive.
The diagram shows how cystic fibrosis was inherited in one family.
How many of the children of A and B were homozygous dominant?

Cystic fibrosis is an inherited disease where certain cells produce abnormal mucus.
The allele for the disease is recessive.
The diagram shows how cystic fibrosis was inherited in one family.
What is the phenotype of D?

Cystic fibrosis is an inherited disease where certain cells produce abnormal mucus.
The allele for the disease is recessive.
The diagram shows how cystic fibrosis was inherited in one family.
What is the probability of F and G having a child with cystic fibrosis?

In tomato seedlings, the first leaves can be either green (filled in) or yellow (not filled in).
The colour of the leaves is controlled by one gene with two alleles. One allele is dominant and one allele is recessive. Two tomato plants were crossed. The seeds from this cross were grown. The results were obtained in the picture.
Calculate the ratio of the two phenotypes.