Punnett squares

Front

What is a Punnett square?

Back

A Punnett square is a diagram used to predict the genetic makeup of offspring from two parents based on their allele combinations.

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene, such as AA or aa.

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene, such as Aa.

Front

What is the probability of obtaining a homozygous offspring from two heterozygous parents (Aa x Aa)?

Back

The probability is 25%.

Front

In a Punnett square, what does each box represent?

Back

Each box represents a possible genotype of the offspring resulting from the combination of alleles from the parents.

Front

What is the genotype of a tall plant if T = tall and t = short?

Back

The genotype could be TT (homozygous tall) or Tt (heterozygous tall).

Front

If a plant has the genotype bb, what is its phenotype?

Back

The phenotype is the expression of the trait, which in this case would be the characteristic associated with the 'b' allele.

Front

How do you determine the probability of a specific genotype using a Punnett square?

Back

Count the number of boxes that show the desired genotype and divide by the total number of boxes.

Front

What is the expected phenotypic ratio from a monohybrid cross between two heterozygous parents (Aa x Aa)?

Back

The expected phenotypic ratio is 3:1 (3 dominant: 1 recessive).

Front

What is the significance of dominant and recessive alleles in genetics?

Back

Dominant alleles mask the effect of recessive alleles in heterozygous individuals.