Chapter 23: Nucleotide Metabolism Flashcards

1
Q

Nucleotides are ?

A

Building blocks of nucleic acid, DNA/RNA

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2
Q

Nucleotide:

A

Phosphate esters of a pentose in which a purine/pyrimadine is linked to C1 of sugar.

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3
Q

Purines:

A

Adenine and guanine

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4
Q

Pyrimadines:

A

Cytosine, thymine, and uracil.

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5
Q

What did John Buchanan do?

A

Determined the origins of the atoms that compromise purines - by looking at uric acid production.

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6
Q

How does the synthesis of purine ribonucleotides work?

A

Initially starts with inosine monophosphate (IMP) with hypoxanthine as its base.

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7
Q

IMP is the precursor for ?

A

AMP and GMP

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8
Q

Purines are initially formed as ___________ rather than as free bases.

A

ribonucleotides

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9
Q

Purine synthesis yields?

A

Inosine monophospahte (IMP)

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10
Q

Diagram of ribose-5-phosphate (R5P) into IMP:

A
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11
Q

Where is purine biosynthesis regulated?

A

IMP, ATP, and GTP pathways

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12
Q

1st purine salvage pathways:

A

Adenine > AMP

Catalyzed by adenine phosphoribosyl transferase. PRPP in, PPi out

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13
Q

2nd purine salvage pathways:

A

Hypoxanthine > IMP
Guanine > GMP

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14
Q

1st committed step of purine biosynthesis?

A

Phosphorylating ribose-5-phosphate to PRPP

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15
Q

How are pyrimidines synthesized?

A

N1, C4, C5, and C6 comes from aspartate/aspartic acid

N3 comes from glutamine

C2 comes from HCO3

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16
Q

How to make UTP into CTP?

A

We need: UTP, CTP synthetase, Glutamine, and ATP

17
Q

Which enzyme converts ribonucleotides into deoxyribonucleotides?

A

Ribonucleotide reductase

18
Q

How does DNA differ from RNA?

A
  1. nucleotides contain 2’ deoxyribose residues
  2. DNA contains thymine instead of uracil
19
Q

Draw of formation of deoxyribonucleotides:

A
20
Q

Why are chemotheraputics given an chemical analogs of UTP?

A

It will shut done pyrimidine synthesis and phospholipid synthesis.

21
Q

Where do all the part of a purine hydrogenous base come from?

A