Genotype Determination in Plants

The video tutorial explains the concept of dominant and recessive alleles, focusing on how to determine the genotype of a plant using a test cross. It describes the process of crossing a plant with a homozygous recessive to identify if the unknown plant is homozygous dominant or heterozygous. The tutorial uses Punnett squares to illustrate the outcomes of these genetic crosses, showing how the results can indicate the genotype of the unknown plant based on the traits of the next generation.

What is the dominant allele for plant height in this problem?

• T

• t

• D

• d

What is the purpose of performing a test cross?

• To produce more seeds

• To increase plant height

• To determine the genotype of an unknown plant

• To determine the phenotype of a plant

In a test cross, what is the genotype of the plant used to cross with the unknown?

• Dwarf

• Heterozygous

• Homozygous dominant

• Homozygous recessive

What is the expected outcome when a homozygous dominant plant is crossed with a homozygous recessive plant?

• All offspring will be dwarf

• All offspring will be tall

• All offspring will be heterozygous

• Half will be tall, half will be dwarf

If the unknown plant is heterozygous, what percentage of the offspring will be tall?

• 25%

• 50%

• 75%

• 100%

What is the genotype of the offspring when a heterozygous plant is crossed with a homozygous recessive plant?

• All heterozygous

• All homozygous dominant

• All homozygous recessive

• Half heterozygous, half homozygous recessive

How can you tell if the unknown plant was heterozygous after a test cross?

• All offspring are dwarf

• All offspring are tall

• Half offspring are tall, half are dwarf

• All offspring are heterozygous

What conclusion can be drawn if all offspring from a test cross are tall?

• The unknown plant is homozygous dominant

• The unknown plant is a hybrid

• The unknown plant is homozygous recessive

• The unknown plant is heterozygous

What is the significance of a 50% tall and 50% dwarf offspring ratio?

• The unknown plant is a hybrid

• The unknown plant is homozygous recessive

• The unknown plant is heterozygous

• The unknown plant is homozygous dominant

What does a test cross help determine about the unknown plant?

• Its color

• Its height

• Its genotype

• Its phenotype