Genetics: Punnett Squares

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, such as AA or bb.

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 an offspring having homozygous alleles if both parents are heterozygous?

Back

50%.

Front

What is the probability of an offspring showing a recessive trait if both parents are heterozygous?

Back

25%.

Front

What is the probability of an offspring being homozygous dominant if one parent is homozygous dominant and the other is homozygous recessive?

Back

0%.

Front

Which allele pair is homozygous: Ee, BB, or Tt?

Back

BB.

Front

What is the probability of an offspring showing the dominant trait if both parents are heterozygous?

Back

75%.

Front

What is a dominant allele?

Back

A dominant allele is an allele that expresses its trait even when only one copy is present (e.g., A in Aa).

Front

What is a recessive allele?

Back

A recessive allele is an allele that only expresses its trait when two copies are present (e.g., a in aa).