IGCSE Biology CIE - Inheritance

What term is used to describe a version of a gene?

• allele

• genotype

• phenotype

• heterozygous

What term is used to describe an organism that carries two identical alleles for a gene?

• dominant

• recessive

• homozygous

• heterozygous

What term is used to describe an organism that carries two different alleles for a gene?

• dominant

• recessive

• homozygous

• heterozygous

What term is used to describe the observable features of an organism due to its genotype?

• inheritance

• phenotype

• dominant

• allele

Gary and Fiona are both healthy but produce a child with a genetic disease caused by a recessive allele.

Which of the following must be true?

• The child could be heterozygous

• Gary is homozygous and Fiona is heterozygous

• Gary and Fiona are both homozygous

• Gary and Fiona are both heterozygous

A plant has two different alleles of a gene, G, resulting in it having a green seed.

Which row of the table describes the phenotype and genotype of the seeds of this plant?

• A

• B

• C

• D

A person has the genotype Aa.

What is the correct description of this genotype?

• heterozygous, with two different alleles of the same gene

• heterozygous, with two different genes of the same allele

• homozygous, with two different alleles of the same gene

• homozygous, with two different genes of the same allele

The pedigree chart shows the inheritance of a genetic disorder in a family.

What conclusion can be made about this genetic disease?

• The genetic disorder is dwarfism

• It is caused by a dominant allele

• It is caused by a recessive allele

• It is caused by codominant alleles

The pedigree chart shows the inheritance of a genetic disorder in a family.

What conclusion can be made about this genetic disease?

• The genetic disorder is dwarfism

• It is caused by a dominant allele

• It is caused by a recessive allele

• It is caused by codominant alleles

The pedigree chart shows the inheritance of a genetic disorder in a family.

It is caused by a recessive allele, h.

What conclusion can be made about the people in the chart?

• Peri must have the genotype HH

• Sarah Jane must have the genotype Hh

• Steven must have at least one H allele

• Martha and Ian must have the genotype Hh