Punnett square

Front

What is a Punnett square?

Back

A Punnett square is a diagram used to predict the outcome of a genetic cross by showing the possible combinations of alleles from the parents.

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene (e.g., AA or aa).

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene (e.g., Aa).

Front

What is the probability of obtaining a homozygous recessive offspring from a cross of two heterozygous parents?

Back

25%.

Front

What is the phenotype of an organism?

Back

The phenotype is the observable physical or biochemical characteristics of an organism, determined by its genotype.

Front

What is the genotype of a plant with red flowers if red (R) is dominant over white (r)?

Back

The genotype can be either RR (homozygous dominant) or Rr (heterozygous).

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 probability of obtaining a heterozygous offspring from a cross of two heterozygous parents?

Back

50%.

Front

If a Punnett square shows a 3:1 ratio of phenotypes, what does this indicate about the parents' genotypes?

Back

It indicates that both parents are heterozygous for the trait.

Front

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

Back

Dominant alleles mask the effect of recessive alleles in determining the phenotype.