Genes and Punnett Squares

Front

What is a gene?

Back

A gene is a segment of DNA that contains the instructions for building a specific protein or set of proteins, which determine traits in an organism.

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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 dominant mean in genetics?

Back

Dominant refers to an allele that expresses its trait even when only one copy is present in the genotype.

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What does recessive mean in genetics?

Back

Recessive refers to an allele that only expresses its trait when two copies are present in the genotype.

Front

What is the genotype of an organism?

Back

The genotype is the genetic makeup of an organism, specifically the alleles it carries for a particular gene.

Front

What is the phenotype of an organism?

Back

The phenotype is the physical expression or characteristics of an organism, resulting from the interaction of its genotype with the environment.

Front

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

Back

The probability is 25%.

Front

What is the expected phenotype ratio from a monohybrid cross?

Back

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

Front

What does it mean if an organism is homozygous?

Back

An organism is homozygous if it has two identical alleles for a particular gene.

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What does it mean if an organism is heterozygous?

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An organism is heterozygous if it has two different alleles for a particular gene.