Genetic Disorders

Study the blood cells in the picture below. Describe the genotype for the individual with these types of cells.

• homozygous recessive

• heterozygous

• homozygous dominant

• codominant

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Which disorder is treated by restricting milk in the diet?

• phenylketonuria

• cystic fibrosis

• galactosemia

• Tay-Sachs disease

Down syndrome is the result of an extra chromosome 21 in a gamete. What caused this to happen?

• nondisjunction

• telomeres

• environment

• chromosome inactivation

Why is Down syndrome called trisomy 21

• The person has 21 pairs of chromosomes instead of 23.

• The person has an abnormal gene on chromosome 21.

• The syndrome is caused by having 21 pairs of autosomes.

• The syndrome results from an extra chromosome 21.

What is the effect of sickle-cell anemia?

• blocked respiratory pathways

• decreased neurological functions

• inefficient oxygen transportation

• susceptibility to contracting malaria

You and your colleagues are constructing a pedigree for a boy with cystic fibrosis. The individual’s younger brother has also been diagnosed with cystic fibrosis. How would these brothers be represented in a pedigree?

• Both would be represented as completely shaded circles.

• Both would be represented as completely shaded squares.

• The older brother would be a shaded square, while the younger brother would be a half-shaded square.

• Both would be represented as unshaded squares.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

A man carrying the allele for Huntington’s disease marries a woman who is homozygous recessive for the allele. What is the probability that their offspring will develop Huntington’s disease?

• 25 percent

• 50 percent

• 75 percent

• 100 percent

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

NGSS.HS-LS3-3

What disease is characterized by abnormally shaped red blood cells?

• hemophilia
• sickle cell anemia
• phenylketonuria
• Huntington's 

Tags

NGSS.HS-LS3-2

NGSS.HS-LS4-2

Which genetic disorder is caused by a dominant allele?

• Huntington's
• Hemophilia
• Cystic fibrosis
• PKU

Which disorder is characterized by the inability to break down a specific amino acid and can be treated by a special diet?

• Huntington's
• Tay Sachs
• Cystic fibrosis
• PKU