GCSE Biology - Family Trees / Family Pedigrees #74

The video tutorial explains family pedigrees, focusing on cystic fibrosis, a recessive inherited disorder. It covers genotypes and alleles, illustrating how to interpret family trees and symbols. The tutorial also demonstrates using Punnett squares to calculate the probability of inheriting cystic fibrosis, emphasizing the importance of understanding genotypes and carriers.

What is required for an individual to have cystic fibrosis?

• Two dominant alleles

• One dominant allele

• One recessive allele

• Two recessive alleles

In a family pedigree, what does a half-shaded shape represent?

• An individual with the disease

• An unaffected individual

• An unknown genotype

• A carrier of the disease

How are generations typically represented in a family tree?

• By different shapes

• By different columns

• By different rows

• By different colors

What is the genotype of an unaffected individual in the given family tree example?

• Homozygous recessive

• Heterozygous

• Homozygous dominant

• Unknown

If both parents are carriers of cystic fibrosis, what is the probability of their child being unaffected?

• 25%

• 75%

• 100%

• 50%

What tool is used to predict the genetic outcome of offspring?

• Family tree

• Pedigree chart

• Punnett square

• Genetic map

What is the chance of a child being a carrier if both parents are carriers?

• 0%

• 25%

• 50%

• 75%