Functions/Dysfunctions Of Protein Processing

Question 1

Silent Mutation

Answer 1

Does not change the amino acid

Question 2

Missense Mutation

Answer 2

Changes amino acid in the protein.

Either no effect or different function.

Question 3

Nonsense Mutation

Answer 3

codon changes into a stop codon.

Causes premature chain termination (null mutation)

Question 4

Sickle Cell Anemia

Answer 4

missense mutation

glutamic acid to valine
deforms RBCs

Question 5

Duchenne Muscular Dystrophy

Answer 5

frameshift mutation

little/no expression of dystrophin protein

muscle wasting,

Question 6

Cytoplasmic Pathway

Answer 6

for proteins going to cytosol, mitochondria, nucleus, and peroxisomes

Question 7

Where does protein synthesis begin and end?

Answer 7

on free ribosomes

Question 8

Cytoplasmic Pathway

Answer 8

for proteins going to cytosol, mitochondria, nucleus, and peroxisomes.

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Question 9

Where does protein synthesis begin and end?

Answer 9

on free ribosomes

Question 10

Secretory Pathway

Answer 10

for proteins going to the ER, lysosomes, plasma membranes, or for secretion

Question 11

Where does translation begin and end?

Answer 11

Translation begins on free ribosomes but ends on ribosomes sent to ER

Question 12

Who are TIM and TOM

Answer 12

transporter in inner membrane and transporter in outer member

Question 13

What do TIM and TOM do?

Answer 13

recognize translocation sequence

Question 14

General properties of secretory pathway

Answer 14

1 or 2 amino acids (Lys or Arg) near N terminus and an extremely hydrophobic sequence on C terminus

Question 15

SRP

Answer 15

signal recognition particle.

binds to the ER-targeting signal and ribosome during translation

Question 16

What does SRP wrap around, and why?

Answer 16

ribosome-mRNA-peptide complex, it pauses translation

Question 17

Enzymes on luminal side

Answer 17

cleave the signal to release the protein

Question 18

Signal Sequence for ER Lumen proteins

Answer 18

KDEL
K-Lysine
D-Aspartic acid
E-Glutamic acid
L-Leucine

Question 19

Signal sequence for lysosomal proteins

Answer 19

Mannose-6-phosphate (M6P)

Question 20

Signal sequence for lysosomal proteins

Answer 20

Mannose-6-phosphate (M6P)

Question 21

Signal sequence for membrane proteins

Answer 21

N terminal apolar sequences

Question 22

Signal sequence for secretory proteins

Answer 22

tryptophan rich domain

Question 23

Glycosylation (2 types)

Answer 23

O-linked are formed with the hydroxyl groups of Ser or Thr

N-linked are ALWAYS with Asparagine. Precursor sugar transferred from phospho Dolichol

Question 24

Phosphorylation Description

Answer 24

Ester bond between phosphate and OH of an amino acid (serine/threonine and tyrosine kinase)

Question 25

What is the purpose of Phosphorylation?

Answer 25

regulate enzyme activity and protein function; cell growth, proliferation, differentiation, oncogenesis

Question 26

Ascorbic acid’s importance

Answer 26

lysyl and prolyl hydroxylases

Question 27

Parkinson’s Disease

Answer 27

impaired fine motor control

Question 28

Huntington’s Diseases

Answer 28

Loss of movement and cognitive functions and psychiatric problems

Question 29

Crutzfeldt-Jacob Disease

Answer 29

failing memory, behavioral changes, lack of coordination. Late stages involve mental deterioration, blindness, weakness of extremities, and coma

Question 30

Alzheimer’s Diseases

Answer 30

Amyloid precursor protein (APP) breaks down to form amyloid beta peptide (AB).
Misfolding, makes plaques - extracellular.
Hyperphosphorylation of Tau (tangles) - intracellular.

Question 31

Parkinson’s Disease

Answer 31

aggregation of a-synuclein (AS) which deposits Lewy bodies in dopaminergic neurons in substantia nigra.

Reduced availability of dopamine.

Question 32

Huntington’s Diseases

Answer 32

mutations in Huntingtin’s gene, causes expansion of CAG triplet repeats.

Polyglutamine repeats, selective death of cells in basal ganglia.

Question 33

Crutzfeldt-Jacob Disease

Answer 33

misfold of prion proteins.
Can be transmitted.
Transmissable Spongiform Encephalopathies (TSEs).