#1 Basic Genetics (Monohybrid Crosses)

Front

What is the Law of Dominance?

Back

The Law of Dominance states that in a heterozygous genotype, one allele can mask the expression of another allele.

Front

What does heterozygous mean?

Back

Heterozygous refers to having two different alleles for a particular gene, such as Rr.

Front

If curly hair (R) is dominant over straight hair (r), what percent of the offspring will be heterozygous (Rr) from a cross of Rr x Rr?

Back

50% of the offspring will be heterozygous (Rr).

Front

What is a phenotype?

Back

A phenotype is the observable physical or biochemical characteristics of an organism, such as blue eyes.

Front

What is a genotype?

Back

A genotype is the genetic constitution of an individual, represented by the alleles (e.g., BB, Bb, bb).

Front

What is the Law of Segregation?

Back

The Law of Segregation states that during the formation of gametes, the two alleles for a trait separate from each other.

Front

What is the Law of Independent Assortment?

Back

The Law of Independent Assortment states that alleles for different traits are distributed to gametes independently of one another.

Front

What is the expected genotype ratio from a monohybrid cross of two heterozygous parents (Rr x Rr)?

Back

The expected genotype ratio is 1:2:1 (1 RR : 2 Rr : 1 rr).

Front

What is the expected phenotype ratio from a monohybrid cross of two heterozygous parents (Rr x Rr)?

Back

The expected phenotype ratio is 3:1 (3 curly hair : 1 straight hair).

Front

What does homozygous mean?

Back

Homozygous refers to having two identical alleles for a particular gene, such as RR or rr.