part 4

Question 1

is a metabolic disease that is
caused by a buildup of Phenylalanine in the body due to an enzyme deficiency, particularly the hepatic enzyme Phenylalanine Hydroxylase (PAH).

Answer 1

PHENYLKETONURIA (PKU)

RECESSIVE

Question 2

It’s the accumulation of phenylalanine, an enzyme inside our body. While it’s normal to have this enzyme, it shouldn’t accumulate.

Answer 2

PHENYLKETONURIA (PKU)

RECESSIVE

Question 3

→ Most commonly occurring in
children, that results in progressive
destruction of the nervous system.
→ caused by the absence of a vital
enzyme called hexosaminidase-A
(Hex-A).
→ Without Hex-A, a fatty substance,
or lipid accumulates abnormally in cells, especially in the nerve cells of the brain.

Answer 3

TAY-SACHS DISEASE (TSD)

recessive

Question 4

is caused by
an inherited detect in a single gene. —— is an autosomal dominant disorder, a person needs only one copy of the defective gene.
→ Isn’t expressed until mid-life

Answer 4

● HUNTINGTON’S DISEASE

dominant

Question 5

• A very important tool for studying human inherited diseases

Answer 5

PEDIGREE ANALYSIS

Question 6

are often used to determine the mode of inheritance (dominant, recessive, etc.) of genetic diseases.

Answer 6

Pedigrees

Question 7

means inherited on chromosome 1-22 while sex-linked means inherited on either X or Y chromosome.

Answer 7

Autosomal

Question 8

• Written horizontally
• Represents the number of
  individuals in the generation

Answer 8

Arabic

Question 9

• Written vertically.
• Represents the generation

Answer 9

Roman numerals

Question 10

• this allele is found on only the X chromosome: can be in males or females)

★ e.g., color-blindness, hemophilia

Answer 10

X-linked recessive

Question 11

• this allele is found on X chromosomes; can be in males or females)
  ★ e.g., hypophosphatemia

Answer 11

X-linked dominant

Question 12

• The allele is found on the Y chromosome and can only be in males.

Answer 12

Y-linked

Question 13

→ Trait is rare in the pedigree
→ Trait often skips generations
(hidden in heterozygous carriers)
Trait affects males and females equally

Answer 13

Autosomal recessive pedigree

Question 14

→ Trait is rare in pedigree.
→ Trait skips generations
→ Males are more often affected
than females
→ Females are carriers
★ Example: Hemophilia A

Answer 14

X-linked recessive pedigrees

Question 15

→ Trait is common in pedigree
→ passed to ALL of their daughters
→ Males and females are equally
likely to be affected
→ X-linked dominant diseases are
extremely unusual
★ ex. incontinentia pigmenti
(skin lesions)

Answer 15

X-linked dominant pedigrees

Question 16

→ Traits on the Y chromosome are
only found in males, never in
females.
→ The father’s traits are passed to XY
on all sons.
→ Dominance is irrelevant: there is
only 1 copy of each Y-linked gene

Answer 16

Y-Linked Inheritance

Question 17

Dominant traits may be rare in a population

t or f

Answer 17

true

Question 18

Recessive traits may be common in a population

t or f

Answer 18

true

Question 19

ALSO known as trisomy 21