The Cell Cycle

Question 1

By what 2 processes do eukaryotic cells divide?

Answer 1

Mitosis or Meiosis.

Question 2

By what process do prokaryotic cells replicate?

Answer 2

Binary Fission

Question 3

Can viruses replicate alone? Why?

Answer 3

No because they are non-living.

Question 4

How do viruses replicate?

Answer 4

Inside of the host cells they invade by injecting their nucleic acid into the cell to replicate the virus particle.

Question 5

What are the 3 stages of the cell cycle?

Answer 5

Interphase
Mitosis
Cytokinesis

Question 6

What 3 stages make up interphase?

Answer 6

G1 phase
S phase
G2 phase

Question 7

How much of the cell cycle does interphase take up?

Answer 7

90%

Question 8

What occurs during interphase?

Answer 8

Organelles double
DNA replicates
The cell grows

Question 9

What does mitosis create?

Answer 9

Two identical diploid cells.

Question 10

Why do cells undergo mitosis?

Answer 10

For growth and repair.

Question 11

Why do cells undergo meiosis?

Answer 11

To create gametes.

Question 12

What does meiosis create?

Answer 12

Four genetically different haploid cells.

Question 13

What is cytokinesis?

Answer 13

When the cytoplasm divides to create two new cells.

Question 14

What occurs in the G1 phase?

Answer 14

Organelles double and cell grows.

Question 15

What occurs in the S phase?

Answer 15

DNA replication

Question 16

What occurs in the G2 phase?

Answer 16

Some more growth but also checking for mutations. Mutated cells are destroyed in this phase.

Question 17

What are the four key stages of mitosis?

Answer 17

Prophase
Metaphase
Anaphase
Telophase

Question 18

How many divisions does mitosis have?

Answer 18

1

Question 19

What occurs in prophase?

Answer 19

The chromosomes become more visible. The centrioles separate and move to opposite poles of the cell.
The nucleolus disappears.

Question 20

What are the centrioles responsible for?

Answer 20

For creating spindle fibres which are released from both poles to create a spindle apparatus.

Question 21

What do plant cells lack?

Answer 21

They have a spindle apparatus but not centrioles.

Question 22

What occurs during metaphase?

Answer 22

The spindle fibres align the chromosomes along the equator of the cell.
The spindle fibres attach to the centromere and chromatid.

Question 23

What occurs during anaphase?

Answer 23

The spindle fibres start to retract and pull the centromere and chromatids. They are pulled to opposite poles of the cell.
This causes the centromere to divide into 2 and the individual chromatids are pulled to each opposite pole.

Question 24

During anaphase, what are the separated chromatids now known as?

Answer 24

Chromosomes.

Question 25

What is required during anaphase?

Answer 25

Energy in the form of ATP. This is provided by respiration in the mitochondria.

Question 26

What occurs during telophase?

Answer 26

The chromosomes become longer and thinner.
The spindle fibres disintegrate and the nucleus starts to reform.

Question 27

Equation for mitotic index?

Answer 27

Mitotic index = The number of cells in mitosis/Total number of cells.