Genetics Review

Front

What does it mean when an offspring has the recessive form of a trait?

Back

It means that one parent has 2 recessive alleles and the other parent has 1 dominant and 1 recessive allele.

Front

What is a section of DNA called?

Back

A gene.

Front

What are the letters Ss an example of?

Back

Heterozygous genes.

Front

What is the genotype of a homozygous dominant organism?

Back

BB.

Front

What is the genotype of a homozygous recessive organism?

Back

aa.

Front

What is the phenotype of an organism?

Back

The physical expression of a trait.

Front

What is the difference between dominant and recessive alleles?

Back

Dominant alleles express their traits even when only one copy is present, while recessive alleles only express their traits when two copies are present.

Front

What is a Punnett square used for?

Back

To predict the genotypes and phenotypes of offspring from genetic crosses.

Front

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

Back

1 BB : 2 Bb : 1 bb.

Front

What does homozygous mean?

Back

Having two identical alleles for a particular gene.