Mooers

Question 1

What are the Watson-Crick base pairs found in DNA?

Answer 1

G-­‐C, A-­‐T

Question 2

What are the Watson-Crick base pairs found in RNA?

Answer 2

G-­‐C, A-­‐U,

Question 3

What are the three stages of DNA synthesis?

Answer 3

initiation, elongation, termination

Question 4

What direction is DNA and RNA synthesized?

Answer 4

The direction is 5’ to 3’ because nucleotides are added to the 3’ end via the 3’OH cleaving the bond between the alpha and beta phosphates

Question 5

What are the kinds of alternating chemical moieties found in the backbone of polynucleotides?

Answer 5

phosphates and sugars are the alternating moieties

Question 6

What features dis.nguishes RNA from DNA?

Answer 6

RNA has 2’OH on the ribose ring, has uracil in place of thymine, can form GU base pairs, usually single stranded, can form a large number of different secondary structures.

Question 7

What is the importance of DNA with respect to DNA synthesis?

Answer 7

It serves as the template strand

Question 8

What does replisome do?

Answer 8

Makes two daughter strands with the leading and lagging strand at the same time

Question 9

What does DNA polymerase need?

Answer 9

a template, dNTPs, and a primer

Question 10

What is released during DNA synthesis?

Answer 10

pyrophosphate

Question 11

What happens after pyrophosphate is released?

Answer 11

subsequent cleavage the anhydride bond of pyrophosphate by inorganic pyrophosphates

Question 12

How much energy is released in this reaction? (DNA synthesis -> release of pyrophosphate -> cleavage of anhydride bond of pyrophosphate)

Answer 12

30kJ/mol; this energy help drive DNA synthesis forward

Question 13

What are the three major problems imposed by DNA helical structure on DNA replication?

Answer 13

supercoiling, primer intimation, and lagging strand synthesis

Question 14

What are the role of telomeres at the ends of chromosomes?

Answer 14

Telomeres insure that the coding region of chromosomes is fully replicated

Question 15

How does the synthesis of the DNA daughter strand occurs when the lagging strand is the template for DNA synthesis?

Answer 15

discontinuously as Okazaki fragments

Question 16

What is the class of nucleotides that are used to stop elongation during DNA sequencinig by lacking a 3’ hydroxyl group?

Answer 16

dideoxyribonuecleotides,

Question 17

Which pair of pyrimidines in a DNA strand are most vulnerable to fusion by UV light?

Answer 17

T-­‐T

Question 18

Where it the damaged DNA cleaved in nucleotide excision repair (NER)?

Answer 18

both upstream and downstream from the damaged site

Question 19

What happens during the prophase of meiosis?

Answer 19

homologous recombination

Question 20

Where does the homologous recombination occur?

Answer 20

between shared sequences in two chromosomal DNAs

Question 21

What is a transposon?

Answer 21

a chromosomal segment that can undergo transposition (via google)

Question 22

What are the types of transposition?

Answer 22

simple/direct transposition & replicative transposition

Question 23

How does simple/direct transposition work?

Answer 23

via cut and paste method; it leaves a double-strand break in the donor strand and it must be repaired

Question 24

How does replicative transposition work?

Answer 24

via formationg of a cointegrate intermediate where the donor and recipient both end up with copies of the transposon

Question 25

Which ribose phosphate moiety is required for the synthesis of purines and pyrimidines?

Answer 25

Phosphoribosyl pyrophosphate (PRPP)

Question 26

What is the first stable intermediate in purine de novo biosynthesis?

Answer 26

Inosine-­‐5’-­‐monophosphate (IMP)

Question 27

Which biosynthetic pathway has a branch point that leads to two parallel pathways?

Answer 27

purine

Question 28

Which biosynthetic pathway produces ribonucleotides sequentially?

Answer 28

pyrimidine

Question 29

Which end-­‐product of the pyrimidine de novo pathway inhibits the enzyme that
catalyzes the first commifed step?

Answer 29

Cytidine 5’-triphosphate (CTP)

Question 30

Where on the ribose ring does ribose nucleotide reductase (RNR) catalyzes the reduction of the ribose ring?

Answer 30

RNR reduces the ribose ring at the C2’ position

Question 31

What does gout lead to?

Answer 31

formation of crystals of sodium urate in joints

Question 32

What is a property of urate? (with respect to study guide)

Answer 32

low solubility so it readily forms crystals

Question 33

What does ribonucleotide reductase reduces?

Answer 33

reduces all four ribonucleotides to deoxyribonucleotides