BIO 3B.2 Punnett Squares

Front

What is a genotype?

Back

A genotype is the genetic makeup of an organism, represented by the alleles it possesses (e.g., YY, Yy, yy).

Front

What is a phenotype?

Back

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

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene (e.g., YY or yy).

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene (e.g., Yy).

Front

What is the principle of dominance?

Back

The principle of dominance states that in a heterozygous genotype, the dominant allele will mask the effect of the recessive allele.

Front

What is a Punnett square?

Back

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

Front

How do you determine the probability of a trait using a Punnett square?

Back

To determine the probability of a trait, fill out the Punnett square with the parents' genotypes and count the occurrences of each genotype.

Front

What is the probability of obtaining a homozygous recessive offspring from two heterozygous parents?

Back

The probability is 25%.

Front

What is the genotype of a white-flowering plant in a species where red (R) is dominant over white (r)?

Back

The genotype of a white-flowering plant is rr.

Front

If one parent has genotype BB and the other has Bb, what are the possible genotypes of their offspring?

Back

The possible genotypes are BB and Bb.