Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Advanced Metabolism > Week 5 > Flashcards

Week 5 Flashcards

1
Q

Glutamate can be made from which three amino acids?

A

Glutamine
Proline
Arginine

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

Which amino acid contributes to the structure of fibrous proteins like collagen?

A

Proline

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

Which two amino acids are both glucogenic and ketogenic?

A

Threonine and tyrosine

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

What are the 3 circumstances as to which amino acids undergo catabolism?

A
  • normal synthesis and degradation of cellular proteins
  • dietary protein surplus
  • during starvation or in uncontrolled diabetes mellitus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which amino acids are sent to the muscles?

A

Branched chain AA

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

What is the first step of AA degradation?

A

The alpha amino group is separated from the carbon skeleton and shunted into the pathways of amino acid metabolism

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

What is the first step of AA degradation catalysed by?

A

Aminotransferases

Transaminases

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

What and where do dietary amino acids collect as/where?

A
  • collect as glutamate

- reaching the liver

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

What are the two general collection points for aa from the tissues?

A

Alanine and glutamine

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

What are the two general collection points for amino groups in the liver?

A

Glutamate and glutamine

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

Where are most amino acids metabolised?

A

In the liver

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

What are the four amino acids which are extremely important in nitrogen metabolism?

A
  • glutamate
  • glutamine
  • alanine
  • aspartate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In skeletal muscle excess amino groups are transferred to pyruvate to make ?

A

Alanine (alanine cycle)

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

Which amino acid has an important role once the AA reach the liver?

A

Aspartate

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

Which prosthetic group do all aminotranferases use?

A

PLP, derived from Vit B6.

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

Where does the nitrogen removal by transamination occur?

A

Cytosol of the liver

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

An increased plasma levels of ALT and AST indicates?

A

Damage to cells rich in these enzymes

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

In the transamination of AA in the form of glutamate which free amino acids can be used to enter the TCA Cycle?

A

All free amino acids except threonine and lysine

alpha keto acids can enter the TCA cycle

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

The aldehyde form of pyridoxal phosphate can react reversibly with?

A

Amino groups

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

The aminated form of Pyridoxamine phosphate can react reversibly with?

A

Carbonyl groups

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

Pyridoxal phosphate is covalently linked to the enzyme via?

A

The active site lysine side chain

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

After dehydration of the pyridoxal phosphate, what type of base linkage is formed? What is the covalent complex called?

A

A Schiff base linkage.

Internal aldimine

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

Which oxidase enzyme produces ammonia and alpha keto acid directly? and what cofactor does it use? (primary form of deamination
)

A

L-amino acid oxidase

FMN

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

What is an example of a secondary means of deamination possible for only hydroxyl amino acids (serine and threonine)?

A

Through the use of a dehydratase mechanism, to form the keto acid and ammonia
- unstable, imine intermediate which hydrolysis spontaneously to yield an alpha keto acid and ammonia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Which amino acids are the exception to entering the TCA cycle?
Leucine and Lysine
26
Once amino acids are collected as glutamate in the liver, what happens to them?
Glutamate undergoes oxidative deamination to release its amino group as ammonia
27
What is enzyme involved in oxidative deamination of glutamate?
Glutamate dehydrogenase Redox + hydrolysis - transamination - only occurs in the liver/kidney (mito) and it is the only enzyme that can use either NAD or NADP as a coenzyme
28
The combined actions of aminotransferases and glutamate dehydrogenase can be either ?
Anabolic or catabolic as the equilibrium constant = 1
29
How is ammonia transported in the bloodstream?
Glutamine Which is catalysed by glutamine synthetase Ammonia is then liberated in the mitochondria by the enzyme glutaminase
30
What is the primary regulatory point in nitrogen metabolism?
Glutamine synthetase
31
How is glutamine synthetase regulated?
- Allosteric regulation - Covalent post translational modification - cumulatative feedback inhibition - multiple inhibitors are additive
32
What donates ammonia to pyruvate in the glucose-alanine cycle to make alanine which in the liver, the ammonia can be removed and the pyruvate can be used to make gluconeogenesis.
Glutamate | The energetic burden is on the liver rather than the muscle
33
Which enzyme is used in the glucose alanine cycle?
Alanine aminotransferase
34
In the liver what are amino acids transferred to to form glutamate?
Alpha ketoglutarate
35
In the liver, glutamine is converted to glutamate by what?
Glutaminase - releasing nitrogen
36
In the liver, glutamate is reduced to ketoglutarate by what?
Glutamate dehydrogenase
37
Alanine releases its nitrogen by ?
Alanine aminotransfersae
38
In skeletal muscle excess amino groups are transferred to pyruvate to form ?
Alanine
39
What are the requirements of the urea cycle?
- one free ammonia and one nitrogen in aspartate | - the carbon and oxygen are derived from CO2 as bicarbonate
40
Where is urea produced and where does it transport to for excretion?
Produced in the liver and is then transported in the blood to the kidneys for excretion in urine
41
Where does the urea cycle begin and then move to?
Begins in the liver mitochondria and then moves to the cytosol
42
Glutamate imported into the mitochondrial matrix is metabolised by glutamate dehydrogenase to produce ammonia and is used to make?
Urea cycle precursor Carbamoyl Phosphate
43
Excess glutamate is metabolised in the ... of hepatocytes?
Mito
44
What is the urea cycle?
The conversion of ammonia to urea
45
How many carbamoyl phosphate synthetases are there?
- mito (aa catabolism) | - cytosolic (nucleotide pyridimine base biosynthesis)
46
How is CPS I regulated?
Allosterically, by the enzyme N-acetylglutamate
47
Ornithine and citrulline are ... and move across the mito membrane via ....
dibasic amino acids | Co transporter
48
Cleavage of argininosuccinate produces?
Arginine - the immediate pre cursor of urea | Fumarate
49
Fumarate can be hydrated to form? oxidised to form? transaminated to form?
Malate Oxaloacetate --> TCA (glucose production) Aspartate
50
In the reaction of malate being oxidised to oxaloacetate what is being reduced and oxaloacetate is being continually removed by the highly exergonic ....
NAD is reduced to NADH and H | Citrate Synthase Reaction
51
How can arginosuccinate be made?
Aspartate and citrulline
52
Where does the cleavage of arginine to urea happen?
In the liver
53
In the final step of the urea cycle arginase cleaves urea from arginine by the addition of ...., regenerating cytosolic ......
H2O | Ornithine
54
In patients with kidney failure, plasma levels of urea are ...?
Elevated
55
In the GI tract, urea is cleaved by bacteria with the enzyme ..., releasing ....
Urease | NH4
56
Intestinal urease activity can contribute to hyperammonemia in patients with ....
Kidney failure
57
What is a diagnostic tool for H.Pylori?
Breath test | - radiolabelled isotope
58
What are the 5 sources of ammonia?
- transamination by aminotransferases and oxidative deamination by glutamate dehydrogenase - non toxic transport of glutamine by action of glutamine synthetase and glutaminase - bacterial action of urease in intestine - digestion/degradation of amines from diet or hormones/neurotransmitters by amine oxidase - catabolism of purine and pyrimidines
59
In the urea cycle which two amino acids move between the hep mito and cyto?
Ornitihine and citrulline
60
Nitric oxide and urea have in common the fact that they both have ... as an immediate precursor?
Arginine
61
Ammonia is transported in the blood from extrahepatic organs as which ?
Alanine and glutamine
62
Alanine catabolism in the liver results in pyruvate production which can be incorporated into which molecule for return to the muscle?
glucose
63
In the muscle name two other amino acids that can regenerate pyruvate?
Isoleucine and valine
64
In Hyperammonemia, serum levels can rise above?
1,000umol/L | Leading to neurotoxin defects
65
What are the two enzyme deficiencies that have effects in the mito?
CPS | OTC
66
What are the three enzyme deficiences that have effects in the cyto?
AG AS ASA
67
What are the the three transporter defects in the urea cycle?
- ornithine carrier - aspartate/glutamate carrier - dibasic amino acid carrier
68
What two aromatic acids can be used to combine glycine and glutamine which can be used in the treatment for deficiencies in the urea cycle?
Benzoate and phenylbutyrate - removes ammonia
69
What are three cofactors involved in the transfer of carbon in amino acid metabolism?
- biotin - tetrahydrofolate - S-adenosylmethionine (SAM)
70
What are the common type of transfers in amino acid metabolism?
One Carbon transfers
71
Which folate can transfer carbon in different oxidation states?
Tetrahydrofolate
72
Which enzyme is involved in the carbon group transfer to which tetrahydrofolate donates the carbon for the synthesis and degradation of glycine?
Serine hydroxymethyl transferase + cofactor THF
73
What form does biotin transfer carbon as?
Biotin transfers carbon in its most oxidised form as CO2 | Biotin Dependent Carboxylations
74
SAM transfers one carbon to? (The most preferred co-factor for many biological reactions)
Methyl groups only | In the most reduced form
75
How is SAM synthesised?
- methionine - ATP - Methionine adenosyl transferase
76
What is required for the conversion of norepinephrine to epinephrine?
SAM
77
Which carbon skeletons breakdown to fumarate?
Phenylanine | Tyrosine
78
Which carbon skeletons breakdown to succinyl CoA?
Met, Ile, Thr and Val
79
Glycine is degraded by three different pathways?
- oxidative cleavage - converted to serine - glycine converted to glyoxylate by D-amino acid oxidase
80
Glycine is converted pyruvate via conversion of glycine to serine by ?
Serine hydroxymethyltransferase
81
Nonketotic hyperglycinemia is caused by a defect in ?
The glycine cleavage enzyme activity - high levels of serum glycine - leads to severe mental deficiency and death in early childhood
82
Oxalate crystals can form ... and if in excess is called?
kidney stones | Urolithiasis
83
A defect in phenylanine hydroxylase results in ?
PKU leading to elevated levels of phenylaline
84
Phenylalanine can be converted to tyrosine, which can produce?
- Tissue Proteins - Melanin - Catecholamines - Fumarate and Acetoacetate
85
What is the disorder that causes urine to turn black?
Alkaptonuria
86
What are the three characteristic symptoms of Alkaptonuria?
- homogentisic aciduria - Excess homogentisic acid - Arthiritis Appear after 30
87
What is the treatment for alkaptonuria?
Diet low in phenylalaine and tyrosine
88
Tyrosine is oxidised by what enzyme?
Tyrosine Hydroxylase
89
Tyrosine is the precursor for which pigment molecules?
Melanins
90
Albinism is a result of ?
Defect in tyrosine metabolism... less melanin | enzyme: tyrosinase
91
Any defect in the pathway through tyrosine to acetoacetyl coA results in ?
Disease State

Advanced Metabolism (8 decks)

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