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02. MCM Test 2 > 2. Functions and Dysfunction of Protein Processing > Flashcards

2. Functions and Dysfunction of Protein Processing Flashcards

1
Q

What is a Missense mutation?

A

A mutation that changes a single amino acid. May do nothing, or change the protien entirely.

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2
Q

What is a Nonsense mutation?

A

A mutation that changes a codon into a stop codon.

(This is also caused a null mutation)

You think you can stop? Nonsense!

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3
Q

What is a Frameshift mutation?

A

When a nucleotide is deleted or added, causing all the others to be wrong.

Like when you accidentally skip a bubble on a scantron and get a 3% on a test

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4
Q

What is a silent mutation?

A

A mutation that does not change the resulting amino acid sequence.

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5
Q

What occupies the 3’ end of mRNA?

A

A poly(A) tail.

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6
Q

What occupies the 5’ end of mRNA?

A

7-Methyl Guanosine

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7
Q

Sickle Cell Anemia comes from what kind of mutation?

A

Missense.

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8
Q

In Sickle Cell Anemia, what amino acid is substituted for which other amino acid?

A

Glutamate (Negative charge and Hydrophillic) becomes Valine (hydrophobic)

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9
Q

In Duchenne’s Muscular Dystrophy - what sort of mutation is found?

A

Frame shift due to deletion, either out of frame (Severe) or in-frame (less severe)

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10
Q

What gene has deletions in Duchenne Muscular Dystrophy?

A

The dystropin gene.

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11
Q

What terminal region of tRNA binds the amino acid?

A

The 3’ CCA Terminal Region

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12
Q

What enzyme serves to “activate” an Amino Acid to tRNA, and helps to ensure the fidelity of the genetic code?

A

Aminoacyl tRNA Synthetase

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13
Q

For Prokaryotic Ribosomes

What is the total Svedberg unit for the entire size?

For the large portion?

For the small portion?

A

Prokaryotes are 70S total

The large subunit is 50S

The small unit is 30S

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14
Q

For Eukaryotic Ribosomes

What is the total Svedberg unit for the entire size?

For the large portion?

For the small portion?

A

Eukaryotes are 80S total

The large subunit is 60S

The small subunit is 40S

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15
Q

In which direction does Translation occur?

A

5’ to 3’

Same as DNA replication

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16
Q

What is the initiation codon, and what does it code for?

A

AUG, Methionine

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17
Q

What high energy compound is hydrolysed to help with loading of aminoacyl tRNA?

A

GTP

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18
Q

What enzyme attaches the second peptide to the first, releasing it from the tRNA?

A

Peptidyl Transferase

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19
Q

Where does the energy for peptide transfer come from?

A

From the high energy bond between the amino acid and tRNA.

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20
Q

What binds to stop codons?

A

Release Factors

(Not any tRNA / amino acid)

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21
Q

What sort of bond is cleaved by release factor, and where is it located?

A

Ester Bond

Between the C terminus of the polypeptide and the tRNA’s CCA terminal region.

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22
Q

When all is said and done, what dissociates the entire ribosomal complex?

A

GTP

23
Q

In which subunit does peptidyl transferase activity occur?

A

The large subunit, for both prokaryotes and eukaryotes.

24
Q

For Streptomycin:

Does it affect Prokaryotes or Eukaryotes?

Where does it bind?

What does it disrupt?

A

It affects prokaryotes

It binds to the 30S subunit

It disrupts initiation of translation via binding formylmethionine-tRNA

25
Q

For Shiga Toxin and Ricin:

Does it affect Prokaryotes or Eukaryotes?

Where does it bind?

What does it disrupt?

A

It affects Eukaryotes

It binds to the 60S subunit

Disrupts elongation

26
Q

For Clindamycin and Erythromycin:

Does it affect Prokaryotes or Eukaryotes?

Where does it bind?

What does it disrupt?

A

It affects prokaryotes

It binds to the 50S subunit

It disrupts translocation of the ribosome

Clinda with the fat red (erythromycin) face yells at the 50 ribosomes to stop running.

27
Q

For Tetracyclines:

Does it affect Prokaryotes or Eukaryotes?

Where does it bind?

What does it disrupt?

A

It affects prokaryotes

It binds to the 30S subunit

It disrupts elongation

28
Q

For Chloramphenicol:

Does it affect Prokaryotes or Eukaryotes?

What does it disrupt?

A

It affects both Prokaryotes and Eukaryotes

It inhibits prokaryotic / mitochondrial peptidyl transferase

29
Q

For Cycloheximide:

Does it affect Prokaryotes or Eukaryotes?

What does it disrupt?

A

It affects eukaryotes

It disrupts peptidyl transferase

30
Q

What does Puromycin cause?

A

Premature chain release, which stops the ribosome.

31
Q

Where does the cytoplasmic pathway send protiens? (4 places)

A
  1. Cytosol
  2. Mitochondria
  3. Nucleus
  4. Peroxisomes
32
Q

Where does the secretory pathway send protiens?

A
  1. Endoplasmic Reticulum
  2. Lysosomes
  3. Plasma Membranes
  4. Secretion

(All of these are secretion / vesicle related places)

33
Q

What feature of amino acids determine sorting into the cytoplasm?

A

A lack of sorting signal altogether.

34
Q

What signal sorts amino acids into the mitochondria?

A

N-Terminal Hydrophobic alpha-helix (no + charges)

Imagine a cork shaped mitochondria, and the N terminal alpha helix is a corkscrew

35
Q

What signal sorts into the Nucleus? (Nuclear Localization Signal)

A

Lysine and Arginine rich ends (four in a row)

  • The Nucleus is invaded by lying pirate protiens (Lys and Arrrrg)*
  • (But once the pirates get up to the membrane, they get scared and need chaperones)*
36
Q

What signal determines transport into the peroxisomes?

A

-SKL

Surviving around all that peroxide takes SKL (skill)

37
Q

What region determines protien ER entrance, and is common to every member of the secretory pathway? (ER Targeting Signal)

A

A positively charged alpha-helix

The protiens of the secretory pathway all start out feeling positive about their prospects. They’re going places! (Secretion)

38
Q

What sequence causes an amino acid to be held in the ER? (ER retention sequence)

A

KDEL (Lysine Aspartate Glutamate Leucine)

_Leu_is _Ly_ed about an Asp biting his Glut, and got to stay in the ER and eat ice cream.

39
Q

Out of the protiens sorted to the secretory pathway, which ones go through the golgi apparatus?

A

Lysosomal, cell membrane, and secretory vesicle protiens

40
Q

What signal determines transport of a protien into the cell membrane?

A

A Stop Transfer sequence

Stop transfering me around the golgi apparatus and stick me in the membrane already!

41
Q

What signal determines a protien be sent to a lysosome?

A

Mannose 6-Phosphate

A lysosome is a trash-_mann_

42
Q

What signal determines a protien be sent from the golgi body to a secretory vesicle?

A

A tryptophan rich domain

The protien didn’t want to leave the cell, but it tripped (tryptophan) into the secretory vesicle.

43
Q

What protien assists a nascent polypeptide get into the ER?

How does it do this?

A

SRP (Signal Recognition Particle)

SRP hugs the ribosome, checks for the positively charged helix, and then binds to SRP-receptor protien in the ER membrane. It does this to bring the ribosome-polypeptide close to an ER membrane protien translocator.

44
Q

What is defective in I-Cell Disease? (aka Inclusion Cell Disease)

What happens as a result?

A

Mannose 6 phosphate

Protiens back up and lysosomes don’t work.

*The inclusions of stuff inside the lysosomes that aren't being broken down are the "inclusions" that give the disease its name.
#DarrenFacts*
45
Q

Oxidation of which amino acids can result in a di-sulfide bond?

A

Cystine

46
Q

What residues can be affected by Acetylation?

A

Lysine

Lysine has the amine group at the end that makes a convenient target for acetylation.

47
Q

What residues can be affected by Glycosylation?

Which ones are O-glycosylation targets?

Which ones are N-glycosylation targets?

A

Serine, Threonine, Asparagine, Glutamine

O-glycosylation: Serine, Threonine (They have the OH)

N-Glycosylation: Asparagine, Glutamine (They have the -CONH2)

  • I’m Serious,There are Assassins, Glen!*
  • (Sugar-high induced paranoid delusions)*
48
Q

What residues are targets for Phosphorylation?

A

Serine Threonine Tyrosine

  • Searing Three Tires*
  • (Amino acids hate phosphates, so these Three kinases really Sear their Tires)*

Note: I find no evidence of relevant phosphorylation of Histidine or Aspartate residues anywhere, but it’s on the table so it goes in the last priority learning slot for me.

49
Q

What two camps are there for the etiology of Alzheimers Disease

A
  1. APP to Amyloid Beta Peptide which forms plaques
  2. Hyperphosphorylation of Tau, which prevents it from doing its job of stabalizing microtubules, causing neurofibrillary tangles.
50
Q

What causes familial Alzheimers?

What is the common factor for sporadic Alzheimers?

A

Mutations in APP and Tau

Brain aging. :(

51
Q

What is the etiology of Parkinsons?

Hint: Protein, deposit, location

What causes the symptoms?

A

Aggregation of alpha-synuclein (AS) protien depositing as fibrils in the Lewy bodies of the Substantia Nigra

Reduced availability of dopamine

52
Q

What causes familial Parkinsons?

What is the common denominator for the sporadic form?

A

Mutations in alpha-synuclein

Brain aging

53
Q

What leads to Huntington’s disease?

What does this cause physiologically?

What causes the symptoms?

A

Mutation in Huntington Gene leads to a bunch CAG (glutamine) repeats

Polyglutamine repeats lead to misfolding and aggregations of the HTT (Huntington) protien

Selective cell death, speciffically in the basal ganglia.

54
Q

What disease is characterized by infection with, or spontanious generation of, a scrapie version of the prion protein?

A

DarrenFacts

Creutzfeldt-Jacob Disease (CJD)

(Note: The word Scrapie is a classical name for a similar disease in sheep, thought to be caused by a misfolded prion protien)

02. MCM Test 2 (14 decks)

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