Nucleotides

Question 1

What is DNA?

Answer 1

Deoxyribonucleic acid

Question 2

What is RNA?

Answer 2

Ribonucleic acid

Question 3

What is rRNA?

Answer 3

ribosomal RNA

Question 4

What is mRNA?

Answer 4

messenger RNA

Question 5

What is tRNA?

Answer 5

transfer RNA

Question 6

What the are three components of a nucleotide?

Answer 6

a nitrogenous base
a pentose
1+ phosphate

Question 7

what is a nucleoside?

Answer 7

the molecule without the phosphate group?

Question 8

What is a pyrimidine?

Answer 8

6 membered ring

Question 9

What is a purine?

Answer 9

6 membered ring fused with a 5 membered ring

Question 10

what are the major purine bases?

Answer 10

adenine (A) in DNA and RNA
guanine (G) in DNA and RNA

Question 11

what are the major pyrimidine bases?

Answer 11

cytosine (C) in DNA and RNA
thymine (T) only DNA
uracil (U) only RNA

Question 12

what are deoxyribonucleotides?

Answer 12

structural units of DNA

Question 13

what ribonucleotides?

Answer 13

structural units of RNA

Question 14

what are the two pathways that lead to nucleotides?

Answer 14

de novo pathways
salvage pathways

Question 15

what are de novo pathways?

Answer 15

begin with metabolic precursors: amino acids, ribose 5-phosphate, CO2 and NH3

Question 16

Bases in de novo are synthesized while attached to what?

Answer 16

a ribose

Question 17

pyrimidine ring is synthesized as

Answer 17

orotate

Question 18

Glutamine provides most:

Answer 18

amino groups

Question 19

Glycine is the precursor for:

Answer 19

purines

Question 20

Aspartate is the precursor for:

Answer 20

pyrimidines

Question 21

what molecule is an important part of both purine and pyrimidine synthesis

Answer 21

PRPP

Question 22

what are salvage pathways?

Answer 22

recycle the free bases and nucleosides released from nucleic acid breakdown

Question 23

What is the Starting point in purine synthesis?

Answer 23

PRPP (ribose sugar w/phosphate attached)

Question 24

What is the end point in purine synthesis?

Answer 24

Inosinate (IMP) is the first intermediate with a complete purine ring

Question 25

From IMP can form either:

Answer 25

adenylate or guanylate

Question 26

In the biosynthesis of AMP and GMP from IMP what donates amino group for adenylate (AMP)?

Answer 26

aspartate

Question 27

In the biosynthesis of AMP and GMP from IMP what donates amino group for guanylate (GMP)?

Answer 27

Glutamine

Question 28

What intermediate is formed in AMP formation?

Answer 28

fumarate

Question 29

Regulation of AMP/GMP Synthesis is generalized or specific?

Answer 29

specific regulation of either one or the other

Question 30

What are the 3 inhibitors of AMP GMP formation, what is specific for GMP?

Answer 30

AMP GMP and IMP GMP is specific for GMP

Question 31

What is the first release intermediate in the salvage of AMP?

Answer 31

Hypoxanthine

Question 32

What is the first release intermediate in the salvage of GMP?

Answer 32

Guanine

Question 33

Pyrimidine synthesis proceeds by first making:

Answer 33

a pyrimidine ring in the form of orotate

Question 34

What is attached after pyrimidine ring formation?

Answer 34

ribose 5-phosphate

Question 35

What provides atoms for the ring structure?

Answer 35

aspartate and carbamoyl phosphate

Question 36

Pyrimidine synthesis starts with:

Answer 36

Aspartate and carbamoyl phosphate

Question 37

Is pyrimidine synthesis specific or generalized?

Answer 37

generalized

Question 38

What inhibits pyrimidine synthesis?

Answer 38

Cytidine 5'-triphosphate (CTP)

Question 39

What is the general pathway from pyrimidine synthesis?

Answer 39

Aspartate and carbamoyl phosphate react and eventually form orotate, PRPP adds orotate at the C-1 position, forming Uridylate (UMP), ATP converts to Uridine 5'-triphosphate (UTP), uracil to cysteine added a glutamine by ATP forming cytidine 5'-triphosphate (CTP)

Question 40

Deoxyribonucleotide Synthesis requires:

Answer 40

ribonucleotide reductase and NADPH

Question 41

What does ribonucleotide reductase do?

Answer 41

removal of hydroxyl group at position 2 and replaces with a hydrogen

Question 42

thymidylate synthesis requires?

Answer 42

Folate (Vitamin B9)

Question 43

What is the primary precursor for thymidylate synthesis?

Answer 43

dUMP

Question 44

Folic Acid Deficiency leads to reduced?

Answer 44

Thymidylate Synthesis

Question 45

Folic acid deficiency occurs in approximately what percentage of the population and what percentage of impoverished countries?

Answer 45

~10% of population ~50% of impoverished countries

Question 46

Reduced thymidylate synthesis causes?

Answer 46

Uracil to be incorporated into DNA

Question 47

Repair mechanisms remove the uracil by?

Answer 47

Creating strand breaks that affect the structure and function of DNA

Question 48

What is thymidylate synthesis associated with?

Answer 48

cancer, heart disease, and neurological impairment

Question 49

catabolism of pyrimidines leads to production of what?

Answer 49

NH4+

Question 50

Carbons of thymine are degraded to?

Answer 50

succinyl coA

Question 51

Carbons of cytosine and uracil are degraded to?

Answer 51

Acetyl coA

Question 52

Where does the nitrogen groups from catabolism of pyrimidines go?

Answer 52

urea production