Brainscape's Knowledge GenomeTM

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


See full index

Whitney - Biochem Test 2 > Lecture 20 Nucleotide Structure, Function, and Metabolism > Flashcards

Lecture 20 Nucleotide Structure, Function, and Metabolism Flashcards

1
Q

DNA binding proteins involved in forming chromosomes are:

A

Histones and non-histone chromosomal proteins

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

Protein + nuclear DNA = ?

A

Chromatin

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

Nucleic Acids

A

Polynucleotides (DNA and RNA)

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

Nucleotides

A

Base, sugar, and phosphate

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

Nucleosides

A

Base and Sugar

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

Nucleotides are the phosphate esters of:

A

Nucleosides

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

Purines

A

2 rings

Adenine and Guanine

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

Pyrimidines

A

1 ring

Thymine, Cytosine, and Uracil

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

Nomenclature of Purines and Pyrimidines

Base - Nucleoside - Nucleotide

A 
Adenine (Ade) - Adenosine (A) - AMP
Guanine (Gua) - Guanosine (G) - GMP
Cytosine (Cyt) - Cytidine (C) - CMP
Uracil (Ura) - Uridine (U) - UMP
Thymine (Thy) - Thymidine (T) - TMP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In DNA, there are ___ base pairs per turn.

A

10

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

DNA exist in two forms. What are they and which one is more prominent?

A

A and B

Most B form (hydrated)

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

Ribonucleases (RNA)

Deoxyribonucleases (DNA)

A

Convert RNA and DNA to short oligomers

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

Phosphodiesterase

A

Convert oligomers to nucleotide monophosphates (NMPs) or deoxynucleoside monophosphates (dNMPs)

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

Nucleotidase

A

Convert NMPs and dNMPs into nucleosides and deoxynucleosides

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

Nucleosidase

A

Remove ribose group and covert them into pyrimidines and purines

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

Adenosine Deaminase (ADA)

A

Plays an important role in adenosine homeostasis and modulates signaling by extracellular adenosine and also contributes indirectly to signaling

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

Overproduction of ADA

A

Causes hemolytic anemia (rare). Increased degradation of adenosine depletes adenine nucleotide pool and triggers premature destruction of RBCs

18
Q

Underproduction of ADA

A

Associated with the second most common form of severe combined immunodeficiency

19
Q

Xanthine Oxidase

A

Catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid

20
Q

Describe the Xanthine Oxidase Molecule

A

2 flavin adenine dinucleotides (FADs), 2 Mo atoms, and 8 Fe atoms per molecule of enzyme

21
Q

Xanthine Oxidase is a drug target for the treatment of:

A

Gout

22
Q

Severe Combined Immunodeficiency (SCID)

A

Defective B and T cells
Most common form is x-linked, hence patients are male
“Bubble Boy”

23
Q

ADA deficiency

A

Most pronounced in lymphocytes
Results in high amounts of adenosine which is then converted into dATP, high levels of which block synthesis of all other dNDPs and dNTPs

24
Q

Gout

A

Characterized by intensely painful and inflamed joints
High levels of uric acid levels in blood resulting from over production of uric acid or under-excretion of uric acid (secondary hyperuricemia)

25
Q

Hyperuricemia

A

Uric acid concentration exceeds pasma solubility

26
Q

Treatment for gout

A

Colchicine (decreases movement of granulocytes to the affected area) and allopurinol that inhibits xanthine oxidase to form the more soluble hypoxanthine

27
Q

Dietary pyrimidines are converted readily to:

A

metabolized ketogenic or glucogenic, water soluble compounds such as malonyl CoA, methyl malonyl CoA, and succinyl CoA

28
Q

The source of ring atoms is purine synthesis:

A

CO2, Gln, Gly, Asp, N10-formyl THF

29
Q

The source of ring atoms in pyrimidine synthesis:

A

HCO3, Gln, Asp, N5, N10-methylene THF

30
Q

The committed step in purine synthesis is the formation of the:

A

Phosphoribosyl amine

31
Q

What is the intermediate formed in all purine synthesis?

A

Inosine Monophosphate (IMP)

32
Q

Name the two salvage enzymes of Purine Biosynthesis

A

Hypoxanthine guanine phosphoribosyl transferase

Adenine phosphoribosyl transferase

33
Q

PRPP (Phosphoribosyl pyrophosphate)

A

Central constituent of nucleotide metabolism

Synthesized from ribose phosphate and ATP

34
Q

In purine synthesis, the ribose is initially contributed by:

A

Phosphoribosylpyrophosphate

35
Q

True or False:

In purine synthesis, the purine ring is synthesized before being attached to the ribose.

A

False.

The purine ring is synthesized attached to ribose phosphate

36
Q

Methotrexate

A

Antineoplastic agent
Inhibitor of DNA synthesis
Binds dihydrofolate reductase 100 fold more tightly; great competitive inhibitor

37
Q

What parts of purine synthesis are feedback inhibited?

A

Synthesis of PRPP and PR-amine

Synthesis of AMP and GMP from IMP

38
Q

AMP synthesis is stimulated by:

A

GTP

39
Q

GMP synthesis is stimulated by:

A

ATP

40
Q

The nucleoside phosphates can be interconverted by exchange of phosphates with each other catalyzed by:

A

Nucleoside monophosphate kinases and diphosphate kinases

41
Q

True or False:

In pyrimidine synthesis, the pyrimidine base is built before it is attached to the ribose sugar.

A

True

Whitney - Biochem Test 2 (6 decks)

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