KC: Genetics: Part 1

Front

What is a genotype?

Back

A genotype is the genetic makeup of an individual, represented by the alleles inherited from the parents.

Front

What is a phenotype?

Back

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

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 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 expresses its trait only when two copies are present (e.g., aa).

Front

What is a Punnett square?

Back

A Punnett square is a diagram used to predict the genotypes of offspring from a cross between two parents.

Front

If both parents are heterozygous (Aa), what is the probability of having a homozygous recessive offspring?

Back

The probability is 25% (1 in 4).

Front

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

Back

The expected genotype ratio is 1 AA : 2 Aa : 1 aa.

Front

What is the expected phenotype ratio from a cross between two heterozygous parents (Aa x Aa) if A is dominant?

Back

The expected phenotype ratio is 3 dominant : 1 recessive.