Mendelian Genetics and Dihybrid Crosses in Pea Plants

The video explores Mendelian genetics using pea plants, focusing on two traits: color and shape. It explains the genotypes and phenotypes of the parental generation, leading to the F1 generation, which is heterozygous for both traits. The video introduces the concept of a dihybrid cross and Mendel's law of independent assortment, which states that alleles of different genes segregate independently. The F2 generation is analyzed using a Punnett square, revealing a 9:3:3:1 phenotype ratio. This ratio is explained as a probabilistic outcome of genetic crosses.

What are the two traits being studied in the pea plants in this video?

• Pea height and size

• Pea shape and size

• Pea color and shape

• Pea color and height

What is the phenotype of a pea plant that is homozygous dominant for both color and shape?

• Green and wrinkled

• Yellow and wrinkled

• Green and round

• Yellow and round

What is the genotype of the F1 generation in this cross?

• Heterozygous for one trait

• Homozygous recessive

• Homozygous dominant

• Heterozygous for both traits

What is a dihybrid cross?

• A cross involving one gene

• A cross involving two genes

• A cross involving three genes

• A cross involving four genes

According to Mendel's law of independent assortment, how do alleles of different genes segregate?

• Sequentially

• Randomly

• Dependently

• Independently

What is the expected phenotypic ratio in the F2 generation from a dihybrid cross?

• 3:1

• 2:1

• 9:3:3:1

• 1:1

How many phenotypes are expected in the F2 generation of a dihybrid cross?

• Two

• Three

• Four

• Five

Which phenotype is least likely to appear in the F2 generation?

• Green and wrinkled

• Yellow and wrinkled

• Yellow and round

• Green and round

What is the probability of getting a yellow and wrinkled phenotype in the F2 generation?

• 1/16

• 3/16

• 9/16

• 4/16

Why might the observed phenotypic ratio differ from the expected 9:3:3:1 ratio?

• Due to errors in the experiment

• Due to environmental factors

• Because of genetic mutations

• Because it is probabilistic