Things to know

Question 1

What are the four requirements for DNA replication?

Answer 1

• DNA polymerase and other proteins and enzymes
• all four deoxyribonucleoside 5’ triphosphates
• free 3’ OH group (required)
• DNA template strand (ssDNA)

Question 2

Describe the structure of a deoxyribonucleotide 5’ monophosphate?

Answer 2

• has a base connected to the sugar 1’ carbon
• deoxyribose is 5 carbons with OH at 3’ carbon, BUT it is missing an O at the 2’ (distinguished it from ribose)

Question 3

How can we distinguish ribose from deoxyribose?

Answer 3

• ribose has an OH on the 2’carbon (it is also more unstable)

Question 4

What is the difference between a nucleotide and a nucleoside?

Answer 4

• nucleoside has no phosphate group attached

Question 5

How many bonds does A and T have? G-C?

Answer 5

G-C: 3 H bonds
A-T: 2 H bonds

Question 6

What is an absolute requirement for DNA replication? How does it obtain this in the elongation stage?

Answer 6

3’ OH
- Short RNA primer synthesizes by primase, serves as a DNA template to extend DNA (later removed and replaced with DNA by E.Coli polymers I)

Question 7

Which is more reactive: DNA or RNA? Why?

Answer 7

RNA is more reactive (less stable) because it has an OH on it’s 2’ carbon

Question 8

which bonds are formed between purines and pyrimidines?

Answer 8

covalent hydrogen bonds

Question 9

is the ratio of purines to pyrimidines always 1?

Answer 9

• in eukaryotic DNA its always 1, however it and RNA varies by species

Question 10

Does rolling circle replication require primase? Why or why not?

Answer 10

• it does NOT, because it doesn’t have a replication bubble so it doesn’t utilize any of the prokaryotic replication processes

Question 11

what is the difference between … 5’ triphosphate and monophosphate?

Answer 11

• ribonucleotide 5’ monophosphate and
  deoxyribonucleotide 5’ monophosphate make up the RNA and DNA
• BUT: ribonucleoside 5’ triphopshate etc are used in synthesis (as template strands)

Question 12

does replication in eukaryotes require primers?

Answer 12

Nope! It uses DNA polymerases (alpha, delta, and epsilon)

Question 13

What kind of activity is used to unwind the hybrid in rho-dependant termination?

Answer 13

Helicase activity!

Question 14

what bond forms the 5’ cap in eukaryotic mRNA?

Answer 14

• an unusual phosphate - phosphate bond