Mendelian Genetics and Dihybrid Crosses

This video tutorial explains Gregor Mendel's dihybrid cross, focusing on a classic example using pea plants. It covers the concept of a dihybrid cross, where two organisms are heterozygous for two genes, and demonstrates how to set up a Punnett square to predict offspring phenotypes. The tutorial details the pea color and pod shape genes, explaining dominant and recessive alleles. It also discusses the law of independent assortment and the expected 9:3:3:1 phenotype ratio in offspring. The video concludes with a summary and suggests further learning resources.

What does the term 'dihybrid' refer to in the context of Mendel's experiments?

• A cross involving one gene

• A cross involving four genes

• A cross involving two genes

• A cross involving three genes

In a dihybrid cross, what does 'hybrid' signify?

• Heterozygous genotype

• Homozygous genotype

• Recessive genotype

• Dominant genotype

What color do pea plants exhibit if they have a homozygous dominant genotype for pea color?

• Blue

• Red

• Green

• Yellow

Which genotype results in green peas?

• Homozygous dominant

• Homozygous recessive

• None of the above

• Heterozygous

What pod shape results from a dominant allele in pea plants?

• Flat

• Square

• Round

• Pinched

Which genotype results in pinched pods?

• None of the above

• Homozygous dominant

• Homozygous recessive

• Heterozygous

How many different gametes can a heterozygous parent produce in a dihybrid cross?

• Two

• Three

• Four

• Five

What principle explains the equal frequency of gametes in a dihybrid cross?

• Law of Recessiveness

• Law of Segregation

• Law of Independent Assortment

• Law of Dominance

How many squares are there in a Punnett square for a dihybrid cross?

• 8

• 4

• 12

• 16

What is the phenotypic ratio for yellow peas and round pods in the offspring?

• 9/16

• 3/16

• 1/16

• 6/16