Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biochem III > Protein and Amino Acid Metabolism > Flashcards

Protein and Amino Acid Metabolism Flashcards

(96 cards)

Start Studying
1
Q

What cells secrete HCl?

A

parietal cells

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

What cells secrete pepsin?

A

chief cells

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

What activates pepsinogen? How many amino acids are auto-catalytically cleaved?

A

low pH (2). 46 residues.

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

What type of peptidase is pepsin? What does this mean?

A

endopeptidase. cleaves internal peptide bonds.

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

Chyme causes the intestinal muscosal cells to secrete what?

A

secretin and cholecystokinin

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

What cells does secretin stimulate? What do they release?

A

acinar cells of pancreas. bicarbonate solution.

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

What structure does CCK stimulate? What does thes do?

A

gallbladder to release bile and pancreas to release digestive enzymes

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

Trypsinogen is actiated to trypsin by what?

A

enteropeptidase

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

How many zymogens does trypsin activate? What are they?

A

three,

chymotrypsinogen, elastase, carboxypeptidases

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

What provides the energy requirement for uptake of specific amino acids?

A

SGLT gradient

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

The uptake of di and tri-peptides utilizes what type of gradient ?

A

proton

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

What type of drug also utilizes the di-peptide transporter?

A

beta-lactam anti-biotics

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

Hartnup Disease lack the ability to take up what? Where is this defective transporter located?

A

large neutral amino acids. intestinal epithelial cells and proximal tubule of the kidney

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

What type of amino acids occur in the urine of patients with Hartnup disease?

A

large, neutral amino acids

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

Hartnup disease shares a presentation profile with what other disease? How is hartnup disease treated?

A

pellarga. Niacin

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

Celiac disease involves an immune response against what protein?

A

alpha-gliadin

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

Where is alpha-gliadin found?

A

gluten

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

The majority of nitrogen excretion occurs in the form of what?

A

urea (85%) in the urine

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

When does a negative nitrogen balance occur?

A

Inadequate protein intake

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

What amino acid is essential in infants?

A

Arginine

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

Alpha-ketoglutarate is made from what product? What enzyme catalyzes this?

A

glutamate.

glutamate dehydrogenase.

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

What amino acid is glutamine made from?

A

glutamate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Reduction of glutamate yields what?

A

glutamate semi-aldehyde

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

What three products can be made from glutamate semi-aldehyde?

A

proline, ornithine and arginine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Alanine is made from what amino acid? What provides the nitrogen for this?
ALanine is made from pyruvtae. ALT provides the nitrogen (from Glu --> aKG)
26
What is aspartate synthesized from? What enzyme provides the nitrogen for this?
OAA. AST (Glu --> a-KG)
27
What amino acid is asparagine synthesized from?
aspartate
28
What is the sequence of synthesizing serine and glycine?
3-phosphroglycerate --> Serine --> Glycine
29
Phenylalanine is synthesized from what amino acid?
tyrosine
30
What two amino acids contribute to the synthesis of cysteine?
methionine and serine
31
What is a common cofactor for transamination reactions?
pyridoxal phosphate (vitamin B6)
32
What enzyme converts glutamine to glutamate?
glutaminase
33
In vivo, what is the likely direction of glutamate dehydrogenase activity?
glutamate --> a-KG
34
What amino acid converts glutamate to glutamine?
glutamine synthetase
35
What is the important contributing molecule to the synthesis of glutamine?
ammonium
36
What does the amide group of glutamaine serve to do?
carrier of ammonium ions
37
What two amino acids do not appear to have corresponding alpha keto acids?
lysine and threonine
38
Are aminotransferases freely reversible?
yes
39
What serves as the nitrogen donor for ALT?
glutamate
40
What serves as the carbon backbone for alanine synthesis?
pyruvate
41
What serves as the carbon backbone for aspartate synthesis? What donates the nitrogen group? What enzyme catalyzes this reaction?
OAA. glutamate AST
42
What reaction does asparagine synthesis catalyze?
converison of aspartate to asparagine
43
Where is ALT found?
primarily the liver and is a specific marker for hepatic damage
44
What is the chain of reactions to produce serine?
3-phosphoglycerate --> 3-phosphohydroxypyruvate --> 3-phosphoserine --> Serine
45
What reaction does serine hydroxymethyltransferase catalyze?
interconversion of serine and glycine
46
What cofactordoes serine hydroxymethyltransferase require?
PLP (B6)
47
What molecule does serine hydroxymethyltransferase use as a carbon acceptor?
THF
48
Specifically, what form of THF is produced by the action of serine hydroxymethyltransferase?
N5, N10 methylene THF
49
What is the most oxidized version of THF?
N10-formyl THF
50
What is the most reduced version of THF?
N5 methyl THF
51
What is the major source of carbon in the one-carbon pool?
Serine
52
What two products react to form S-adenosylmethionine?
methionine and ATP
53
What enzyme is defective in homocystinuria?
cystathionine beta-synthase
54
What are some classical symptoms of homocystinuria?
dislocation of optic lens osteoporosis lengthening/thinning of long bones
55
Where is phenylalanine hydroxylase found?
liver
56
What is the function of dihydrobiopterin reductase?
DHBtn --> THBtn
57
In PKU, what in phenylalanine converted to?
phenylpyruvate
58
PKU patients have high levels of what in their urine?
phenylpyruvate
59
In PKU patients, other than phenylalanine hydroxylase, what other enzyme can be deficient?
DHBtn Reductase
60
What cell type can be affected by an increase in phenylalanine levels?
myelin
61
Phenylalanine is a competitive inhibitor of what enzyme?
tyrosinase
62
What is tyrosinase responsible for?
melanin
63
What type of amino acids does pepsin like to cleave?
aromatic and hydrophobic
64
Where is enteropeptidase found?
on the surface of intestinal mucosal villae
65
After the action of pacreatic proteases, what is the percent composition of peptides vs. free amino acids?
60% = peptides 40% = free amino acids
66
What gradient is used for uptake of amino acids?
sodium electrochemical
67
What isoform, D or L, has a higher affinity for amino acid transport?
L
68
How are amino acids released from intestinal epithelial cells into portal circulation?
facilitated diffusion
69
celiac disease is common disorder among what population of people?
Caucasian
70
What is meant by amino acid pool?
amino acids that join the circulation
71
What contributes to the amino acid pool?
sum of intracellular and extracellular amino acids
72
What is the function of glutamate dehydrogenase?
to convert glutamate to aKG
73
What is the function of glutaminase?
to convert glutamate to glutamine
74
Glutamate serves as the nitrogen donor for what two enzymes?
AST and ALT
75
ALL aminotransferases have the requirement for what co-factor?
vitamin B6 AKA pyridoxal phosphate
76
What two amino acids do not appear to have a corresponding aminotransferase?
threonine and lysine
77
Are the reactions catalyzed by the aminotransferases reversible?
yes. freely reversible
78
How does asparagine synthesis differ from glutamine synthesis?
glutamine = NH4 Asparagine = amide received from glutamine
79
Serine hydroxymethyltransferase uses THF as an acceptor of what?
methylene
80
What type of THF does serine hydroxymethyltransferase produce?
N5N10 THF
81
What is the most oxidized version of THF?
N10-formyl-THF
82
What is the most reduced version of THF?
N5-methyl-THF
83
What form of THF tends to accumulate in tissues?
N5-methyl-THF
84
What amino acid is the major source of carbon for the one-carbon pool?
Serine
85
What are other contributors to the one carbon pool?
glycine, formaldehyde, histidine, formate
86
What products can be administered to a patient with homocystinuria?
pyridoxine, cysteine and betaine
87
What three digestive enzyme does trypsin activate?
chymotrypsinogen, elastase, carboxypeptidases
88
What is the co-factor required for all aminotransferases?
pyridoxal phosphate (B6)
89
What signals the release of trypsin?
CCK
90
What stimulates the release of secretin and CCK?
chyme entering duodenum
91
What three things can trigger acute pancreatitis?
alcohol, gallstones, infections
92
How do dietary amino acids enter the one carbon pool?
3-phosphoglycerate
93
What one amino acids and two metabolic intermediates also contribute to the one-carbon pool?
formaldehyde, histidine, formate
94
Is the action of phenylalanine hydroxylase reversible?
no. not reversible.
95
What compound if often found in the urine of patients suffering from PKU?
phenylpyruvate
96
Why does PKU cause hypopigmentation?
Phe is a competitive inhibitor of tyrosinase (melanin production)

Biochem III (9 decks)

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