Lecture 2 - DNA Replication

studied byStudied by 2 people
5.0(1)
get a hint
hint

What must DNA do before cell division?

1 / 21

encourage image

There's no tags or description

Looks like no one added any tags here yet for you.

22 Terms

1

What must DNA do before cell division?

DNA must be replicated to make 2 identical copies for the daughter cells

New cards
2

Origin of replication

Specific sites (sequences) where DNA replication starts

New cards
3

Replication bubble

expanding area of replicated DNA

New cards
4

Replication fork

site of active replication, two per replication bubble

New cards
5

DNA polymerase can...

add new nucleotides to the 3' end of a DNA strand

New cards
6

Limitations of DNA Polymerase

1. cannot unwind double-stranded DNA

2. cannot start a chain, can only add a nucleotide to an existing nucleotide strand

3. can only add nucleotides to 3' end

4. cannot link existing DNA chains together

New cards
7

DNA Helicase

- found in replication forks

- unwinds double-stranded DNA

- BUT overwinds the DNA in front of it (requiring Topoisomerase)

New cards
8

Primase

builds short RNA strands called primers that allow DNA Polymerase to build a DNA strand

New cards
9

Leading strand

- continuous

- synthesize towards the fork (5' -> 3')

*think leading so will start at the higher prime (5') end+

New cards
10

Lagging strand

- discontinuous (in Okazaki fragments)

- synthesize away from the fork (3' -> 5')

- fragments closer to the origin of replication are built first

New cards
11

Sliding clamp

Allows DNA Polymerase to keep going without falling off

New cards
12

Single stranded binding proteins (SSBPs)

prevent lagging strand from folding on itself and blocking replication

New cards
13

Multiple DNA polymerase are used in DNA replication, what are they?

DNA polymerase 3 and 1

New cards
14

Exonucelase

cuts nucleotides off end of nucleic acid strand

New cards
15

DNA polymerase 3

- main DNA polymerase (builds the RNA strands)

- 5' -> 3' polymerase

- 3' -> 5' exonuclease (for proofreading)

New cards
16

DNA polymerase 1

- specialized DNA polymerase, removes the polymerase so strands can build where it once was

- 5' -> 3' polymerase

- 3' -> 5' exonuclease (for proofreading)

- 5' -> 3' exonuclease (for replacing RNA primers)

New cards
17

DNA Ligase

connects adjacent strands of DNA together to combine fragments to form one continuous strand

New cards
18

Nucleotide triphosphate and its purpose

- new nucleotides enter as nucleotide triphosphates (3 phosphates connected to the nucleotide, ex. ATP)

- two out of the three phosphates are loss which releases energy to power the connection of the nucleotide to the strand

New cards
19

Why are nucleotides added to 3' end?

Allows for proofreading and removal of incorrect nucleotides

New cards
20

Telomeres

- non-protein coding repetitive sequence found at ends of chromosomes

- act as buffer to protect protein coding genes

- shorten w/each replication

- limits replicative potential for cells (ex. cells can replicate forever and forever; prevents cancer but may contribute to aging)

New cards
21

Telomerase

- protein-RNA complex

- because telomeres shorten w/ each replication it means the chromosome itself also shortens w/ each replication

- Telomerase counters this by extending the 3' end of DNA strands

New cards
22

Who discovered telomeres and telomerase?

Elizabeth Blackburn

New cards

Explore top notes

note Note
studied byStudied by 17 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 83 people
Updated ... ago
5.0 Stars(4)
note Note
studied byStudied by 8 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 149 people
Updated ... ago
5.0 Stars(4)
note Note
studied byStudied by 13 people
Updated ... ago
5.0 Stars(2)
note Note
studied byStudied by 89 people
Updated ... ago
5.0 Stars(2)
note Note
studied byStudied by 33 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 13 people
Updated ... ago
5.0 Stars(1)

Explore top flashcards

flashcards Flashcard78 terms
studied byStudied by 8 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard21 terms
studied byStudied by 16 people
Updated ... ago
4.0 Stars(1)
flashcards Flashcard29 terms
studied byStudied by 6 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard100 terms
studied byStudied by 13 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard23 terms
studied byStudied by 10 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard22 terms
studied byStudied by 10 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard50 terms
studied byStudied by 13 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard250 terms
studied byStudied by 125 people
Updated ... ago
5.0 Stars(1)