Cell Dividon And Cell Death

Question 1

What are the specificities of DNA polymerase ?

Answer 1

• it needs a template
• it can only add nucleotides to a 3rd end
• it verifies its own work : proofreading activity
• it needs a DNA primer

Question 2

What are the different phases of the cell cycle ?

Answer 2

G0 : resting state (up to years)

Interphase
G1 : physical growth
S phase : duplication of DNA = 10 to 12 hours
G2 : preparation for division

Mitotic phase
M phase with mitosis and cytokinesis

Question 3

What is the role of helicase ?

Answer 3

It’s the first enzyme to arrive at the origin of duplication. It breaks the hydrogen bounds in the netrogenous pairs.

Question 4

What is the role of RNA primase?

Answer 4

It produces an fragment of RNA complementary to the DNA template, providing a free 3´ end to DNA polymerase.

Question 5

Explain why DNA replication is semi-continuous

Answer 5

The 2 anti parallel strands are replicated simultaneously but the leading strand is synthesized continuously while the lagging strand is synthesized in fragments called Okazaki fragments.

Question 6

Detail the functions of the «clean up crew»

Answer 6

• Exonuclease removes the RNA primers
• a specific DNA primer fills in the Okazaki gaps
• DNA ligase joins DNA fragments

Question 7

What is a karyotype,describe the human one

Answer 7

Karyotype is the appearance and number of chromosomes for a certain species.
The human karyotype is made of 46 chromosomes
Humans are diploid = 2 sets of matching chromosomes = 23 matching pairs

Question 8

Define cell division

Answer 8

It’s the process by which a parent cell divides in 2 or more daughter cells

Question 9

Autosomes definiton

Answer 9

There are 2 sex chromosomes and the other 44 are called autosomes

Question 10

Mitosis definition.

Answer 10

Is the part of the division process where the DNA of the cell’s nucleus is split into 2 equal sets of chromosomes

Question 11

Name the phase of mitosis

Answer 11

Prophase
Metaphase
Anaphase
Telophase