GCSE Biology - Genetic Diagrams #73

The video tutorial explains genetic diagrams and Punnett squares, focusing on allele combinations from two parents. It uses a mouse trait example to illustrate dominant and recessive alleles, and how to draw genetic diagrams. The tutorial also covers Punnett squares, showing how they simplify genetic predictions. An advanced example demonstrates heterozygous offspring mating, highlighting genotype and phenotype ratios. The video concludes with a reminder of the role of multiple genes and environmental factors in trait determination.

What does a dominant allele represent in genetic diagrams?

• A trait that is always expressed

• A trait that is expressed only in the presence of a recessive allele

• A trait that is expressed only in the presence of another dominant allele

• A trait that is never expressed

What is the first step in drawing a genetic diagram?

• Drawing a Punnett square

• Calculating the probability of traits

• Determining the parent's phenotypes and genotypes

• Finding the offspring's phenotypes

In a genetic diagram, what does a heterozygous genotype mean?

• No alleles

• Two dominant alleles

• Two recessive alleles

• One dominant and one recessive allele

What is a Punnett square used for?

• To determine the environmental impact on genes

• To calculate the exact number of offspring

• To predict the genotypes of offspring

• To show the phenotypes of parents

How many squares are in a typical Punnett square grid?

• Two

• Four

• Eight

• One

What is the probability of having a muscular offspring when two heterozygous mice mate?

• 0%

• 25%

• 50%

• 75%

What factors, besides genes, can influence a trait?

• Only genes

• None of the above

• Random chance

• The environment