Punnett squares

What is a Punnett square?

• A type of genetic mutation

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

• A method for cloning organisms

• A technique for measuring genetic diversity

What do the letters in a Punnett square represent?

• They represent the phenotypes of the offspring.

• They represent the genotypes of the parents.

• They represent alleles, where uppercase letters denote dominant alleles and lowercase letters denote recessive alleles.

• They represent the environmental factors affecting the traits.

How do you determine the phenotype ratio from a Punnett square?

• By counting the number of offspring with each phenotype and expressing it as a ratio.

• By calculating the total number of alleles present in the offspring.

• By analyzing the genotypes of the parents only.

• By observing the physical traits of the parents before breeding.

What is an allele?

• A type of chromosome that determines the sex of an organism.

• A variant form of a gene that can produce different traits.

• A process by which cells divide and replicate.

• A structure that carries genetic information in the form of DNA.

How can you identify the missing allele in a Punnett square?

• By analyzing the known alleles of the parents and the resulting offspring.

• By randomly guessing the alleles of the parents.

• By using a genetic calculator to determine the alleles.

• By consulting a geneticist for expert advice.

What is the phenotype of an organism?

• The genetic makeup of an organism.

• The observable physical or biochemical characteristics of an organism, determined by its genotype.

• The evolutionary history of an organism.

• The habitat in which an organism lives.

What is the genotype of an organism?

• The physical appearance of an organism.

• The genetic makeup of an organism, represented by the combination of alleles (e.g., AA, Aa, aa).

• The environment in which an organism lives.

• The process by which traits are passed from parents to offspring.

What does it mean if an organism is homozygous recessive?

• An organism has two copies of the dominant allele (e.g., AA) resulting in the expression of the dominant phenotype.

• An organism has one copy of the dominant allele and one copy of the recessive allele (e.g., Aa).

• An organism has two copies of the recessive allele (e.g., aa), resulting in the expression of the recessive phenotype.

• An organism has no copies of the recessive allele, resulting in a neutral phenotype.

What does it mean for an allele to be recessive?

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

• A recessive allele is one that always expresses its trait regardless of the other allele.

• A recessive allele is one that can mask the expression of a dominant allele.

• A recessive allele is one that is never expressed in the phenotype.

What does it mean for an allele to be dominant?

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

• A dominant allele is one that requires two copies to express its trait.

• A dominant allele is one that can only be expressed in the absence of a recessive allele.

• A dominant allele is one that is always expressed regardless of the presence of other alleles.