Biochemistry

Question 1

Explain the difference between the following mutations: a. silent, b. missense, c. nonsense, d. framshift

Answer 1

a. silent: nucleotide substitution, but it does not result in a different AA
b. missense: nucleotide substitution resulting in changed AA (sickle cell)
c. nonsense: nucleotide substitution resulting in early stop codon
d. frameshift: deletion or insertion of a number of nucleotides not divisible by 3 (Tay-Sachs, Duchenne, familial hypercholesterolemia)

Question 2

In eukaryotes, are the introns are exons what makes the mRNA?

Answer 2

exons.

Question 3

What does p53 do?

Answer 3

Regulates the cell cycle from going from G1 to S.

Question 4

What happens in the S phase of the cell cycle?

Answer 4

DNA is replicated.

Question 5

How many types of collagen are there?

Answer 5

4
I. most common, bone, skin, tendons, dentin, fascia, cornea, late wound repair
II. cartilage, nucleus pulposus,
III. reticulin- skin, blood vessels, uterus, fetal tissue, granulation tissue
IV. basement membrane, basal lamina, lens

Question 6

What does the mnemonic “Be (So Totally) Cool, Read Books” refer to?

Answer 6

The types of cartilage.

I. Bone, Skin, Tendons
II. Cartilage
III. Reticulin (skin, blood vessels, uterus, fetal tissue, granulation tissue)
IV. Basement membrane

Question 7

Tell me about osteogenesis imperfecta.

Answer 7

• AD, decreased Type I collagen.
• lots of fractures
• blue sclerae
• hearing loss
• dental problems

Question 8

What does the mnemonic “SNoW DRoP” refer to?

Answer 8

blotting procedures:

Southern: DNA
Northern: RNA
Western: Protein

Question 9

What is the Hardy-Weinberg equation? What are 4 requirements?

Answer 9

p^2 + 2pq + q^2 = 1, p + q = 1

p^2 = frequency of homozygotes for p
q^2 = frequency of homozygotes for q

4 rules:

a. no mutations
b. no natural selection
c. random mating
d. no net migration

Question 10

What diseases are a result of B1 deficiency?

Answer 10

Wenicke-Korsakoff: confusion, confabulation, ataxia, opthalmoplegia.

Wet Beriberi: high-output cardiac failure, edema
Dry Beriberi: polyneuritis, symmetrical muscle wasting

(think: Ber1Ber1)

Question 11

In the electron transport chain, how many ATP per NADH? Per FADH2?

Answer 11

NADH = 3 ATP
FADH2 = 2 ATP

Question 12

Heinz bodies and bite cells are signs of what?

Answer 12

G6P deficiency.

Question 13

What are the glucogenic essential AAs?

Answer 13

methionine, valine, histidine

Question 14

What are the glucogenic/ketogenic essential AAs?

Answer 14

isoleucine, phenylalanine, threonine, tryptophan

Question 15

What are the ketogenic essential AAs?

Answer 15

leucine, lysine

*PDH deficiency gets ketogenic AAs are tx

Question 16

What is the mnemonic “Ordinarily, Careless Crappers Are Also Frivolous About Urination.”

Answer 16

Urea cycle:

Ornithine
Carbamoyl phosphate
Citrulline
Aspartate
Argininosuccinate
Fumarate
Arginine
Urea

Question 17

What are the branched amino acids? What disease is associated with them?

Answer 17

Isoleucine, Leucine, Valine.

I Love Vermont Maple Syrup (maple syrup urine disease)

Question 18

Tell me about Fabry disease

Answer 18

ANGIOKERATOMAS, renal/CV disease, pheripheral neuropathy.

alpha-galactosidase A is the deficient enzyme

ceramide trihexoside is the accumulated substrate

XR (Hunter Syndrome is too)

Question 19

Tell me about Gaucher disease

Answer 19

ASEPTIC NECROSIS OF FEMUR, hepatosplenomegaly, pancytopenia

glucocerebrosidase (beta-glucosidase) is the deficient enzyme

glucocerebroside is the accumulated substrate

AR

Question 20

Tell me about Neimann-Pick disease

Answer 20

“CHERRY-RED” spot on macula, progressive neurodegeneration, hepatosplenomegaly, foam cells

sphingomyelinase is deficient enzyme

sphingomyelin is the accumulated substrate

AR

he PICKS his nose with his SPHINGER

Question 21

Tell me about Tay-Sachs

Answer 21

“CHERRY-RED” spot on macula, progressive neurodegeneration, developmental delay

hexosaminidase A is deficient enzyme

GM2 ganglioside is the accumulated substrate

AR

saX laX heXosaminidase

Question 22

Tell me about Hurler syndrome

Answer 22

CORNEAL CLOUDING, gargoylism, airway obstruction, hepatosplenomegaly

alpha-L-iduronidase is deficient enzyme

heparan sulfate and dermatan sulfate are accumulated substrates

AR

Question 23

Tell me about Hunter syndrome

Answer 23

mild Hurler syndrome + aggressive behavior (no corneal clouding)

iduronate sulfatase is the deficient enzyme

heparan sulfate and dermatan sulfate are accumulated substrates

XR (Fabry disease is too)