Ch. 20 Homework

Question 1

The term ______ refers to the outward expression of a trait, either physically, microscopically, or metabolically.

Answer 1

Phenotype

Question 2

This is determined by which ______ their chromosomes possess for a specific trait.

Answer 2

Alleles

Question 3

The combination of alleles of an organism is referred to as the organism’s ______.

Answer 3

Genotype

Question 4

For diploid organisms, each cell contains ______ alleles for each trait, referred to as the dominant and recessive alleles.

Answer 4

Two

Question 5

If an organism possesses two dominant alleles, the term ______ ______ can be used to describe its genotype, and it will exhibit a dominant phenotype.

Answer 5

Homozygous dominant

Question 6

If, however, it possesses two recessive alleles, the term ______ ______ can be used to describe its genotype, and it will exhibit a recessive phenotype.

Answer 6

Homozygous recessive

Question 7

The term ______ ______ can be used to describe the genotype of an organism that possesses one dominant and one recessive allele, and this individual will still express a dominant phenotype.

Answer 7

Heterozygous dominant

Question 8

Skin color and height are examples of polygenic traits that are controlled by ______ sets of alleles.

Answer 8

Several

Question 9

Polygenic traits are graphically represented as a ______ curve.

Answer 9

Bell-shaped

Question 10

In polygenic inheritance, ______ alleles all code for product and have a ______ effect on phenotype.

Answer 10

Dominant; quantitative

Question 11

The effects of polygenic inheritance are additive and result in a ______ ______ of phenotypes.

Answer 11

Continuous variation