DNA Replication, the Cell Cycle and Mitosis Flashcards Preview

Nucleic Acid and Gene Expression > DNA Replication, the Cell Cycle and Mitosis > Flashcards

Flashcards in DNA Replication, the Cell Cycle and Mitosis Deck (20):
1

Which enzyme unravels DNA?

Topoisomerase

2

Which enzymes separates the two strands?

DNA helicase

3

Which enzyme adds nucleotides to unwound DNA strands?

DNA polymerase

4

Does the separation of the two strands of DNA require ATP?

Yes

5

What two molecules are needed for DNA polymerase to do its job?

Oligonucleotide primers and dNTP's (deoxynucleotide triphosphate)

6

Which direction does DNA synthesis occur?

5' to 3'

7

What is the point where DNA synthesis begins called?

Origin of replication

8

Explain how the lagging strand is synthesised

DNA primase primes the DNA with an RNA primer that it synthesises. DNA polymerase then adds nucleotides to the 3' end of the primer. When it meets the previous Okazaki garment the RNA primer of the previous one is removed by ribonuclease and replaced by Repair DNA polymerase then DNA ligase joins the two DNA strands.

9

Which enzyme synthesises the RNA primer for the lagging strand?

DNA primase

10

Which enzyme removes the RNA primer?

RIbonuclease

11

Which enzymes joins the DNA of Okazaki fragments?

DNA ligase

12

What makes sure the DNA polymerase is in the right place?

Sliding clamp

13

What prevents the single stranded DNA from locally folding?

Single stranded DNA binding protein

14

Which enzyme replace RNA with DNA?

Repair DNA polymerase

15

What is the DNA proofreading mechanism and what enzyme carries it out?

DNA polymerase checks the previous nucleotide is correct before adding another

16

What happens during G1? How many hours?

Nothing just chilling. 10 hours.

17

What is S phase? How many hours?

Synthesis of DNA. 9 hours.

18

What is G0?

Where there is no more cell replication

19

What is G2? How many hours?

Each chromosome has two identical chromatids. 4 hours.

20

What happens during prophase. metaphase, anaphase and telophase?

Prophase – chromosomes condense, each containing two sister chromatids.
Metaphase – chromosomes align in the centre of the cell, attach to the spindle microtubules by the centromeres.
Anaphase – the spindle separate the two chromatids which move to either side of the cell.
Telophase – sister chromatids are on opposite sides of the cell. Cytokinesis occurs.