Punnett Square Practice

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 the term 'phenotype' mean?

Back

Phenotype refers to the observable physical characteristics or traits of an organism, determined by its genotype.

Front

What is the difference between 'homozygous' and 'heterozygous'?

Back

Homozygous means having two identical alleles for a trait (e.g., AA or aa), while heterozygous means having two different alleles for a trait (e.g., Aa).

Front

What does 'dominant allele' mean?

Back

A dominant allele is an allele that expresses its trait even when only one copy is present in the genotype.

Front

What does 'recessive allele' mean?

Back

A recessive allele is an allele that only expresses its trait when two copies are present in the genotype.

Front

How do you determine the probability of offspring traits using a Punnett Square?

Back

You fill in the Punnett Square with the alleles from each parent and then count the combinations to find the probability of each phenotype.

Front

What is the probability of getting a homozygous recessive offspring from a cross of Aa x Aa?

Back

The probability is 25%.

Front

If a purple flower (P) is crossed with a white flower (p), what is the genotype of the offspring?

Back

The possible genotypes are Pp (purple) and pp (white).

Front

What is the expected phenotype ratio from a cross of two heterozygous parents (Aa x Aa)?

Back

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

Front

What is the significance of a test cross?

Back

A test cross is used to determine the genotype of an individual with a dominant phenotype by crossing it with a homozygous recessive individual.