Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biochem + Metabolism > Amino Acids & Proteins > Flashcards

Amino Acids & Proteins Flashcards

1
Q

Only __ are used as building blocks for protein

A

L- Amino Acids

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

The R group of an amino acid

A

Determines the unique and specific properties and functions
Does most of the buffering

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

How many pKa values do amino acids have?
(two answers)

A

at least 2
a 3rd occurs when the R group is ionizable, these are buffers

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

which amino acids are ionizable

A

glutamic acid (glutamate), aspartic acid (aspartate), lysine, arginine, histidine

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

which amino acids are hydrophobic?

A

Ala, Val, Leu, Ile, Pro, Met, Phe, Trp

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

which amino acids are hydrophilic

A

polar r-group: Ser, Cys, Thr, Tyr, Asp, Glu

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

Which amino acid is neither hydrophobic nor hydrophilic

A

glycine

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

Name the essential amino acids

A

Met, Thr, Arg, His, Val, Phe, Ile, Trp, Lys, Leu

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

When do amino acid modifications occur?

A

After the protein has already been made

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

Hydroxyproline and Hydroxylysine are essential for what?

A

Proper collagen structure

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

What vitamin is required for hydroxylation of lysine and proline to then later be used in collagen structures?

A

Vit. C (Absorbic avid )

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

What is the most abundant protein in mammalian organisms? at around 30%

A

Collagen

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

TRUE or FALSE: Ingested modified animo acids will be incorporated into their respective proteins?

A

FALSE

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

Desmosin and isodesmosine are formed from what animo acid? What protein are they prevalent in?

A

Lysine and they are prevalent in elastin (smooth muscle)

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

How does carboxylation of glutamic acid affect proteins? What important cascade is this involved in?

A

carboxyglutamate is a was of protein activation, this is essential in the clotting cascade.

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

What are the four levels of protein structure?

A

Primary: Amino acid sequence (peptide bonds)
Secondary: localized structural elements ( alpha helixes, beta pleated sheets)
Tertiary: Protein folding
Quaternary: Interaction of multiple subunits

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

Why is proper protein folding essential?

A

Structure is essential to proper function, misfolding can lead to pathologies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define amyloid

A

term for a protein that misfolds and aggregates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Name 3 examples of misfolded protein pathologies:

A

Scrapie
Bovine spongiform encephalopathy
Chronic wasting disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Define enzymes

A

biological catalysts that increase reaction rate by lowering the activation energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Define coenzymes

A

organic or organometallic molecules that assists an enzyme and are REQUIRED for enzyme activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

List two types of enzyme activity control

A
  1. Feedback inhibition: increase of end products inhibits regulatory enzyme activity
    2.Proteolytic activation: cleavage of part of a protein resulting in activation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does Km represent?

A

measures enzyme activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what does a low Km signify? and a high Km?

A

low= enzyme has high affinity for substrate
high=enzyme has low affinity for substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Define a competitive inhibitor, how does it affect Km, is it reversible? if so how would you reverse it?
Competes with substrate for enzyme. The Km is the same. Is reversible by increase in substrate concentration.
26
Define noncompetitive inhibitors? How do they affect the Km and Vmax? are they reversible? if so how
Binding away from the active site causing a change in the structure thus affecting its ability to function. Km is increased and Vmax in decreased. It is reversible but only when the inhibiter is removed
27
What makes a "suicide inhibitor" irreversible?
They interact COVALENTLY (very stable bond) with the enzyme to form a stable complex that permanently inactivate the enzyme
28
Describe the stomach's role in protein degredation
the acidic environment of the stomach begins protein denaturation. Hydrolysis of peptide bonds by pepsin into smaller polypeptides
29
what enzyme in the stomach hydrolyzes protein peptide bonds?
pepcin
30
Describe the role of the small intestine in protein digestion
-majority of protein digestion -proteases breakdown polypeptides into amino acids
31
What enzyme breaks down polypeptides in the stomach?
proteases
32
Where are proteases secreted? and into what part of the small intestine?
They are secreted from the pancreas into the duodenum
33
Describe how the protease proenzymes are activated in the duodenum
enteropeptidase cleaves trypsinogen into trypsin, trypsin then activates the other enzymes
34
List the two pathways for protein turnover
1. Lysosomal degradation 2. Ubiquitin-proteasome pathway
35
Describe lysosomal degredation
proteins are transferred to lysosomes via macrophages or vesicles to be broken down. this mainly occurs via the highly acidic nature of the lumen. Lysosomes also have >40 digestive enzymes
36
Describe Ubiquitin-Proteasome pathway protein degradation
Major pathway for intercellular protein degradation. ubiquitin is activated by E1 (ATP required), then ubiquitin is transferred to E2, the ubiquitin is added to the target protein by E3 catylization. Once there is a ubiquitin chain on the target protein it is then recognized by the proteasome for destruction.
37
Which organ generates over half of free amino acid pool
Muscle
38
What organ is the major site of amino acid catabolism?
Liver
39
What type of amino acids does the liver prefer to metabolize?
aromatic amino acids
40
Describe the interorgan exchange of amino acids in the fed state
Meal- gut releases all but glutamine + asparagine - BCAAs will go to the muscles- most other amino acids go to the liver for catabolism
41
Describe the interorgan exchange of amino acids in the postabsorptive state (fasting/starvation)
Muscle releases glutamine, alanine, and valine- glutamine goes to the kidney/gut- alanine goes to the liver- valine goes to the brain
42
How do amino acids get to the liver?
through portal circulation ( the portal vein)
43
List two ways to catabolize amino acids
1.Transamination 2.Deamination
44
Describe the process of transamination
the amino group of the amino acid is interchanges with the keto (C=O) of a keto acid
45
What cells does transamination amino acid catabolism occur?
the liver (hepatocytes)
46
What coezyme does transaminases require?
active vit.B6
47
Name two hepatic transaminases
Alanine aminotransferase (ALT) Aspartate aminotransferase (AST)
48
After transamination where does aminated glutamine go?
the liver for oxidative deamination
49
Describe oxidative deamination
The amino group gets removed from glutamine, then it is converted to NH4+, a keto group replaces amino group. products are NH4+ (then to be used in the urea cycle) and alpha ketoglutarate ( to later be used in TCA cycle)
50
What enzyme catalyzes oxidative deamination in the liver
glutamate dehydrogenase (GLDH)
51
Why is oxidative deamination favored in the liver as compared to other cells?
Because one of the end products is ammonia ion, which is highly toxic
52
What is the purpose of the urea cycle? and where does it mainly occur?
to detoxify ammonia. the cycle take place mainly in the liver
53
How many ATP are required to complete the urea cycle? Where do they enter?
3 total. 2 enter at the rate limiting step with N-acetylglutamate and carbamoyl phosphate synthetase I to form carbamoyl phosphate. The other enters with L-aspartate ( this step provides the second nitrogen)
54
What 5 enzymes are required by the urea cycle?
carbamoyl phosphate synthetase I, orrithine carbamoyl transferase, arginosuccinate synthetase, arginosuccitate lyase, arginase
55
What 5 amino acids are required by the urea cycle?
N-acetylglutamate, L-Ornithine, L-Citrulline, L-Aspartate, L-Arginine
56
Which enzyme required by the urea cycle is liver specific?
Arginase
57
What is the rate limiting step of the urea cycle?
The activation of carbamoyl phosphate synthetase I
58
What amino acid provides the second nitrogen to the urea cycle?
L- aspartate
59
Where does the urea cycle take place in hepatocytes?
The mitochondria and the cytosol
60
What nonprotein amino acid is essential in cats?
Taurine
61
From what amino acid is Taurine derived?
Methionine
62
What three derivatives are produced from Tyrosine?
Catecholamines (Dopamine, norepinephrine, epinephrine) Melanin Thyroid hormones
63
What two derivatives are produced from Tryptophan (Trp,W)?
Serotonin Melatonin
64
What derivative is produced from Histidine (His, H)?
Histamine
65
What derivatives are produced from Glutamate (Glu, G)?
GABA +cysteine = glutathione
66
Name the important features of glutathione
Glutamine + cysteine -An abundant sulfur containing molecule in the cells -Antioxidant
67
What type of neurotransmitter is glutamate in the CNS?
Excitatory
68
What type of neurotransmitter is Glycine in the CNS?
inhibitory
69
What derivatives are produced from Glycine?
-Purine + methionine+arginine = creatine
70
What derivative is produced from Arginine?
NO (vasodilator and neurotransmitter)
71
What derivatives are produced from Serine?
Ethanolamine + choline formation which is important in phospholipid formation
72
What derivatives are produced from Methionine?
+ lysine = carnitine (shuttles long fatty acids across mitochondrial membranes) - S-adenosyl methionine (SAMe) = used in practive as methyl group transferases (denamarin)
73
What amino acids are BOTH glucogenic and ketogenic?
WIFTY Tryptophan Isoleuicine Phenylalanine Threonine Tyrosine
74
What amino acids are ONLY ketogenic?
Leucine Lysine
75
What Amino Acids are ONLY Glucogenic?
Alanine, Valine, Proline, Methionine, Serine, Cystine, Glycine, Arginine, Histidine, Aspartate, Glutamate, Asparagine, Glutamine

Biochem + Metabolism (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions