Brainscape's Knowledge GenomeTM

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


See full index

Biochem Exam 3 > 1 Carbon Metabolism > Flashcards

1 Carbon Metabolism Flashcards

1
Q

C1 Carriers

A

Biotin, SAM, FH4

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

C1 Source, Group, Reaction – Biotin

A

CO2

Carboxyl Groups

Carboxylation Reactions

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

C1 Source, Group, Reaction - SAM

A

Methionine

Methyl Groups

Methylations

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

C1 Source, Group, Reaction – FH4

A

Trp, Ser, Gly

formyl methenyl, methylene, methyl

Synthesis of purines, pyrimidines and thymidine, Homocysteine –> Methionine

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

The C1 Carbons in ___ and ___ groups are in the same oxidation state

A

formyl and methenyl

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

FH4 participates in how many methylation reactions?

A

One. All others use SAM.

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

Biotin is cofactor for which four enzymes

A
  1. Pyruvate Carboxylase
  2. Acetyl CoA carboxylase
  3. Propionyl CoA Carboxylase
  4. (ß-methylcrotonyl CoA Carboxylase – Leucine catabolism)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Holocarboxylases go on to partipate in what processes?

A

Protein Catabolism

FA synthesis

Gluconeogenesis

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

Biotin Cycle

A

Biotin + apocarboxylases

|

(Holocarboxylase Synthase)

|

Holocarboxylases

|

Biocytin (–> Recycled)

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

Biotin is recycled from ____ by ____

A

Biocytin, biotinidase

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

Holocarboxylase Synthase deficiency may lead to…

A

Encephalopathic crisis (drain bamage)

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

SAM Synthesis

A

Met + ATP ———(Met Adenysyl Transferase)——-> SAM

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

Guanidoacetic acid methylation product

A

Creatine

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

Phosphatidylethanolamine methylation product

A

Phosphatidylcholine

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

rRNA and tRNA methylation product

A

methylated RNA

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

Norepi methylation product

A

Epi

17
Q

Protein-bound LYS methylation product

A

Trimethyllysine

18
Q

SAM fate

A

hydrolyzed to adenosine and homocysteine

19
Q

Homocysteine fate

A

Converted to Met, or used in Cys synthesis

20
Q

FH4 reduced by what enzyme?

What cofactor is needed?

A

Dihydrofolate Reductase

NADPH

21
Q

The busines part of THF

A

N5 & N10

22
Q

Methyl, Formyl, Methylene, and Methenyl bind to THF…

A
  • Methyl N5
  • Formyl N10
  • Methylene and Methenyl form a bridge between N5 and N10
23
Q

a.a. that THF transfers from

A

Trp, His, Gly, Ser

24
Q

Formation of N5-Methyl FH4

A

FH4 –> N10 Formyl –> N5, N10 Methenyl –> N5, N10 Methylene (+NADH) –>

N5Met-FH4

25
Q

Methotrexate Mechanism

A

Folate anaolg, inhibits Dihydrofolate Reductase

26
Q

5-Fluorouracil Mechanism

A

Inhibits Thymidylate Synthase

(UMP –//–> dTMP)

27
Q

B12-dependent reactions

A
  1. Homocysteine –> Methionine (Methionine Synthase)
  2. Methylmalonyl CoA –> Succinyl CoA
28
Q

B12 absorption

A

bound by haptocorrins –> Proteases release –> GIF binds and enters Ileum

29
Q

Explain the methyl trap

A

B12 is the only thing that can remove methyl groups from N5Methyl FH4 (which is needed for Regeneration of Methionine from Homocysteine). Homocysteine trapped.

Low B12 = High homocysteine = Megaloblastic anemia, CNS Symptoms

30
Q

How to DDX B12 and Folate deficiencies?

A

Level of Methylmalonyl CoA (will be HIGH with a B12 deficiency since it is a required cofactor)

31
Q

Causes of Homocysteinuria

A
  1. Folate Deficiency
  2. B12 deficiency
  3. Reduced activity of Cystathione ß Synthase

(CBS Rxn = HC+Serine+B6–> Cystathione)

32
Q

Betaine is a…

A

An alternate pathway for Homocysteine—> Methionine

33
Q

Betaine Pathway

A

Betaine ( + Homocysteine) –> Dimethylglycine ( + Methionine)

34
Q

Is B vitamin supplementation useful for reducing the risk of atherosclerosis? Why or why not?

A

No. No evidence despite their effect on plasma homocysteine levels.

35
Q

B12 deficiency effects? What causes this?

A

Megaloblastic anemia, Neurological symptoms (neuropathy)

Neuro Sx d/t high Methylmalonyl-CoA, which may decrease lipid synthesis or decrease SAM.

36
Q

Megaloblast definition

A

Large erythroblast associated with B12 deficiency.

DNA synthesis is impaired (RNA is unaffected) becuase dTTP is limiting factor

Biochem Exam 3 (10 decks)

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