Inheritance

Question 1

What does a square represent on a pedigree diagram?

Answer 1

Male

Question 2

What does a circle represent on a pedigree diagram?

Answer 2

Female

Question 3

What does a coloured in shape represent on a pedigree diagram?

Answer 3

Affected individual

Question 4

What does a diagonal line through a shape mean on a pedigree diagram

Answer 4

Deceased

Question 5

What does a triangle represent on a pedigree diagram?

Answer 5

Miscarriage

Question 6

What does a diamond represent on a pedigree diagram?

Answer 6

Unknown sex

Question 7

What does an arrow pointing to a shape mean in a pedigree diagram?

Answer 7

They are the individual providing the pedigree information

Question 8

How would you show the unborn baby of a pregnant mother on a pedigree diagram?

Answer 8

Draw their shape and put a P in the middle

Question 9

What is a genotype?

Answer 9

The genetic makeup

Question 10

What is a phenotype?

Answer 10

The physical characteristic

Question 11

Where do an individuals two copies of each gene come from?

Answer 11

Mother and father

Question 12

What does homozygous mean?

Answer 12

Two alleles of a gene are the same

Question 13

What does heterozygous mean?

Answer 13

Two alleles of a gene are different

Question 14

What does hemizygous mean?

Answer 14

Only one allele of a gene on the X chromosome

Males only

Question 15

What does dominant mean?

Answer 15

The dominant allele in a heterozygote determines the phenotype

Question 16

What does recessive mean?

Answer 16

The non-dominant allele in a heterozygote is called recessive

Question 17

What is codominance?

Answer 17

When neither alleles is dominant over the other e.g. A and B in blood groups

Question 18

What are the characteristics of an autosomal recessive disease?

E.g. Who is affected? Are they affected equally? Give an example of the disease

Answer 18

Heterozygous is unaffected
Males and females are affected equally
Skips generations
Cystic fibrosis

Question 19

What are the characteristics of an autosomal dominant disease?

E.g. Who is affected? Are they affected equally? Give an example of the disease

Answer 19

Heterozygotes are affected 
Males and females are affected equally 
Homozygous not viable for life 
Cannot skip generations 
Huntington's disease

Question 20

What are the characteristics of a x linked recessive disease?

E.g. Who is affected? Are they affected equally? Give an example of the disease

Answer 20

Hemizygous males and homozygous females affected
Disease more common in males
Males cannot pass to sons
Haemophilia A

Question 21

What are the characteristics of an x linked dominant disease?

E.g. Who is affected? Are they affected equally? Give an example of the disease

Answer 21

Hemizygous males and heterozygous females are affected
Affected males cannot give trait to sons but will give to all daughters
E.g. Rett syndrome

Question 22

Who is affected by Y linked inheritance?

Answer 22

All male children

Question 23

Who is affected by mitochondrial abnormalities?

Answer 23

Passed from mother so all of her children

Question 24

What is abnormal about albinism?

Answer 24

It is polygenic so more than one gene produces the phenotype as Genes on the chromosome are linked

Question 25

What are polygenic genes?

Answer 25

Do not show independent assortment at meiosis

Genes close together are tightly linked