Inherited Disorders (GCSE Biology)

A person inherits two alleles for each gene, one from each parent. What is the term for an individual who has two different alleles for a gene?

A pedigree chart shows a child with a dominant inherited disorder born to two parents, one affected and one unaffected. What is the most likely genotype of the affected parent?

What does it mean if an inherited disorder shows variable expressivity?

Which term describes small differences between individuals of the same species that are not caused by genes but by the environment?

Which phrase best describes an allele that is maintained in a population because heterozygotes have a survival advantage?

Which of the following is an ethical concern commonly raised about genetic screening and testing for inherited disorders?

A genetic test detects whether an unborn foetus has inherited two copies of a recessive disease allele. What type of test that samples cells from the placenta is commonly used for this purpose during pregnancy?

Which term describes a person who carries a recessive disease allele but does not show the disease symptoms?

A scientist finds a new inherited disorder in a family and wants to show the disorder is caused by a single gene mutation. Which evidence would best support a single-gene inheritance pattern?

Preimplantation genetic diagnosis (PGD) can be used during IVF to test embryos for inherited disorders. What is one main advantage of PGD compared with testing during pregnancy?

What is a likely consequence of inbreeding (mating of close relatives) in small populations regarding inherited disorders?