Lesson 4 Biology

What are characteristics of polygenic traits? Select all that apply.

• Traits are continuous across a range.

• On a histogram, traits distribute on a bell-shaped curve.

• Traits are discrete.

• Traits are always found in a 9:3:3:1 ratio.

Which factor determines if someone has brown eyes or green eyes?

• several dominant alleles

• one allele from each parent

• several genes acting together

• one gene acting alone

A few genes are responsible for melanin pigmentation in human skin. Each gene has one allele that codes for melanin production and one allele that does not.

Which of the following are true? Select all that apply.

• Some alleles contribute to the phenotype, and others do not.

• The combination of alleles determines how pigmented the skin will be.

• Only one of the genes has an effect on the phenotype.

• Each allele only contributes a small amount to the phenotype.

How can epistatic interactions affect the number of phenotypes that can appear?

Select all that apply.

• Epistasis can create new phenotypes.

• Epistasis can make phenotypes change based on the environment.

• Epistasis can mask genes and prevent them from affecting the phenotypes.

• Epistasis can modify existing phenotypes.

What is the difference between blood types in the ABO blood type system?

• number of alleles

• size of blood cell

• presence of rhesus factor

• antigens on red blood cells

Two people have the genotype IAIB. Of the following options, what possible genotypes could their children have?

• IBIB

• IAIB

• IAi

• IAIA

A person has blood type B.

What combination of alleles could she have to give her this blood type?

Select all that apply.

• IBIB

• IAIB

• ii

• IBi

Two parents both have homozygous genotypes. One parent has blood type A and the other has blood type B. What genotype can be expected in all of their children?

• O

• AB

• A

• B

Blood type is an example of which of the following?

Select all that apply.

• a situation in which a gene has three or more alleles

• a situation in which more than one allele for a trait is dominant

• a situation in which no allele is dominant over another

• a situation that involves two recessive alleles