Nucleic Acids Flashcards Preview

BIOC2001 Dina > Nucleic Acids > Flashcards

Flashcards in Nucleic Acids Deck (19)
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1
Q

Which bases are purines?

A

adenine and guanine

2
Q

Which bases are pyrimidines?

A

thymine, cytosine and uracil

3
Q

Why are some numbers described with a prime (‘)?

A

Positions on the ribose ring are described with a prime (‘) to distinguish them from positions on the base ring.

4
Q

What is a nucleoside?

A

base + sugar

5
Q

What are the names of the four nucleosides?

A

deoxyadenosine
deoxyguanidine
deoxythymidine
deoxycytidine

6
Q

What is a nucleotide?

A

base + sugar + phosphate

7
Q

What are the names of the four nucleotides?

A
deoxyadenosine-5'-triphosphate = dATP
deoxyguanosine-5'-triphosphate = dGTP
deoxycytidine-5'-triphosphate = dCTP
deoxythymidine-5'-triphosphate = dTTP
8
Q

What is Chargaff’s Rule?

A

In DNA, the number of
A = T
G = C

9
Q

Which base pair is joined by two hydrogen bonds?

A

A-T

10
Q

Which base pair is joined by three hydrogen bonds?

A

G-C

11
Q

What is an endonuclease?

A

cleaves bonds internally

12
Q

What is an exonuclease?

A

starts at one end and cleaves bonds one at a time

13
Q

What is the function of a nuclease?

A

cleaves phosphodiester bonds

14
Q

What does EcoR1 stand for?

A

Eschericha coli R1

15
Q

What does Pst1 stand for?

A

Pseudomonas stuartii 1

16
Q

What does Hpa1 stand for?

A

Haemophilus parainfluenzae 1

17
Q

What is the function of DNA ligase?

A

catalyses the formation of a phosphodiester link between the 5’-phosphate and 3’-OH of adjoining nucleotides in duplex DNA

18
Q

What is the mechanism of ligation by DNA ligase?

A
  1. adenylation of ligase
  2. activation of 5’-phosphate at 5’ terminus (transfer of AMP moiety)
  3. displacement of AMP seals the nick
19
Q

What is an example of an alkaline phosphatase?

A

calf intestinal phosphatase (CIP)

removes 5’-phosphate from DNA or RNA