Mendelian genetics

Front

What is a genotype?

Back

The genetic makeup of an organism, represented by the alleles it possesses (e.g., NN, nn, Nn).

Front

What is a phenotype?

Back

The observable physical or biochemical characteristics of an organism, determined by its genotype (e.g., blue eyes, curly tails).

Front

What does it mean for an allele to be dominant?

Back

A dominant allele is one that expresses its trait even when only one copy is present in the genotype (e.g., C in Cc).

Front

What does it mean for an allele to be recessive?

Back

A recessive allele is one that only expresses its trait when two copies are present in the genotype (e.g., cc).

Front

What is a hybrid organism?

Back

An organism that has two different alleles for a trait (e.g., Cc).

Front

What is a Punnett square?

Back

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

Front

How much does each box in a Punnett square represent?

Back

Each box represents a 25% chance of that genotype occurring in the offspring.

Front

What is the expected phenotype ratio from a monohybrid cross of a hybrid and a recessive?

Back

The expected phenotype ratio is 3:1 for dominant to recessive traits.

Front

What is the expected genotype ratio from a monohybrid cross of a hybrid and a recessive?

Back

The expected genotype ratio is 1:2:1 for homozygous dominant, heterozygous, and homozygous recessive.

Front

What is the difference between homozygous and heterozygous?

Back

Homozygous means having two identical alleles for a trait (e.g., NN or nn), while heterozygous means having two different alleles (e.g., Nn).