Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochem > Exam 2 Peng > Flashcards

Exam 2 Peng Flashcards

1
Q

<p>what are the nonessential AA?</p>

A

<p>all of the ones that start with A, C, or G AND proline, serine, tyrosine (Probably Sleeping Tymorrow)</p>

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

<p>what are pyrimidines?</p>

A

<p>thymine, cytosine, uracil</p>

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

<p>what are purines?</p>

A

<p>adenine and guanine</p>

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

central dogma

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the four most abundant elements?

A

oxygen, carbon, hydrogen, nitrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is our primary source of nitrogen? how do we uptake it?

A

AA
bacteria in soil > plants > animals/us
(we can’t break down N in air bc of strong triple bond)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are our two methods of protein degradation? why do we need this?

A

1) dietary protein degradation -by digestive system
2) cellular protein degradation -in cells already
- -proteins are too large and need to be hydrolyzed or broken down, need proteins for AA we can’t make

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

where are protelytic enzymes found?

A

SI, stomach, pancreas

Point: to get free AA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the first step in deitary degradation?

A

hydrochloric acid in the stomach

1) kills bacteria 2) denatures proteins 3) activate proenzymes pepsinogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what activates proenzyme pepsinogen?

A

hydrochloric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what happens to pepsinogen once it is activated?

A

turns into pepsin to digest large proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

why can;t cell produce active pepsin? What happens instead?

A

it’ll damage the cell. so they produce inactive enzyme (zymogen) and later it’ll get activated when in correct location. HCL changes pepsinogen to become partially activated, and then pepsinogens interaction together to become active pepsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

inactive form of pepsin?

A

pepsinogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what further cleaves peptides produced by pepsin?

A

pancreatic protease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how is pancreatic protease different from pepsin? How are they the same?

A

pancreatic protease exhibits substrate AA specificity. They both are secreted as inactive proenzyme (zymogens) and are activated through proteolytic activity (cascade effect)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is a common pancreatic protease activator?

A

trypsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is aminopeptidase? found where?

A

found in luminal surface of the intestine. it is a exopeptidase that repeatedly cleaves N-terminus from oligopeptides to produce free AA

18
Q

Big difference between aminopeptidase andpepsid or pancreatic proenzyme?

A

they cut from the END of a small protein at the N-terminus and NOT from within

19
Q

what is the main goal or outcome from all peptidases?

A

to produce free AA

20
Q

abnormaliites in protein degradation?

A

deficiency in pancreatic enzymes due to cystic fibrosis, removal or inflammation, celiac disease in SI, diabetes, or other digestive/kidney diseases

21
Q

Main site for AA metabolism?

A

liver

22
Q

what takes up AA and small proteins in the intestine? then what?

A

enterocytes. then absorbed into the blood or metabolized in liver

23
Q

why is active transport required to move AA into a cell?

A

bc concentration of free AA in the cell is higher than outside it, requires hydrolysis of ATP for active transport to go against gradient

24
Q

what is cystimuria?

A

the inability to reabsorb cystein, ornithine, arginine or lysine which means they accumulate in urine due to a genetic mutation. BUT CYSTEINE is fairly INSOLUBLE and resutls in KIDNEY STONES

25
Q

what is the most common inherited diseases for dietary protein degradation?

A

cystimuria

26
Q

what is protein turnover?

A

the rate at which proteins are constantly being synthesized and degraded; roughly 300-400g per day

27
Q

what is the net amount of protein determined by?

A

the rate of both protein synthesis and degradation; varies per person and protein

28
Q

what are the two ways that cellular proteins are degraded?

A

1) lysosomal degradation- degrade IN lysosome bc proteins SENT there
2) ubiquitin mediated degradation- like driving a car around trying to find proteins

29
Q

lysosomal degradation is ____ dependent? contains? two types of lysosomal degradation?

A

ATP dependent and uses acid hydolases to degrade proteins; heterophagy and autophagy

30
Q

heterophagy vs autophagy lysosomal degartion

A
  • *heterophagy- degrades extracellular substrates via endocytosis (defense)
  • *autophagy- degrade intracellular proteins (in own cell)
31
Q

What is lysosomal storage disease?

A

defects in lysosomes resulting in inherited metabolic disorders such as developmental delay, deafness, blindness, organ probs
*diagnosed by enzyme assay and treatment is symptomatic or bone marrow transplant

32
Q

how does ubiquitin mediated degradation for cellular protein degradation work?

A

proteins that are being degraded are first “tagged” with ubiquitin and THEN recognized by proteolytic enzymes responsible for degrading ubiquitinated cellular proteins

33
Q

how is ubiquitin added onto a protein?

A

the C-terminus glycine residue ON UB is added to the lysine residue of the target protein

34
Q

at least how many Ub need to be added for degradation? If not, what occurs?

A

you need at least FOUR UB tages (only a chain can degrade a protein); if less than 4 (monoubiquitnation) than only the function of the protein is modified and not degraded

35
Q

what are the steps in protein ubiquitination? Is it ATP dependent? What creates variation?

A

1) Ub acitvating enzyme (E1)
2) Ub conjugating enzyme (E2)
3) Ub ligase
* ATP DEPENDNET aka needs energy, enzyme catalyzed
* there are MANY E1 and E2 enzymes to give this process specificity

36
Q

what are defects for Ub- dependent proteolysis?

A

cancer, neurodegenerative diseases, metabolic disorders

37
Q

treatment of Ub defects?

A

drugs that target proteolytic machinery are potentially valuable
*if protein degradation is blocked it causes a lot of toxicity in the cell which is an advantage to treat cancer cells

38
Q

what is the N-terminal rule for degradation?

A

AA present at amine terminus influences turn-over rate
Met= stable
Arg or Leu = degrade rapidly at N-terminus

39
Q

why degrade AA?

A

1) downregulation for quantitiy control
2) renewal for quality control
3) providing materials for synthesis of other molecules
4) providing energy (10-15%)

40
Q

what is the obligatory step for all AA catabolism?

A

the removal of alpha-amino group

41
Q

what happens to AA carbon skeletons during degradation?

A

they are degraded to intermediate products

42
Q

catabolism

A

breakdown (large to small), makes energy, makes pre-cursers

Biochem (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions