Cell Cycle And Mitosis

Question 1

What is mitosis needed for?

Answer 1

-Produce new cells for growth and replacement of damaged cells.
-To reproduce asexually.

Question 2

What is the product of mitosis?

Answer 2

Two genetically identical cells.

Question 3

What are the stages of the cell cycle?

Answer 3

-G1
-S
-G2
-Mitosis
-Cytokinesis

Question 4

What happens in the G1 phase and how long for?

Answer 4

-Growth of cytoplasm and new organelles.
-Cell grows in size.
-Protein synthesis from new organelles.
-For 10 hours.

Question 5

What happens in the S (synthesis) phase and for how long?

Answer 5

-Synthesis for DNA
-DNA is replicated.
-For 9 hours.

Question 6

What happens in the G2 phase and how long for?

Answer 6

-Organelles grow and divide.
-Energy stores are increased (ATP is synthesised) within the cell so it increases further in size.
-For 4 hours.

Question 7

What is the total length of the cell cycle?

Answer 7

24 hours

Question 8

What is the G0 phase?

Answer 8

-Where a cell would move out of the cell cycle.
-Only happens if the cell/ DNA of the cell is damages or the cell has differentiated and specialised.

Question 9

How is the cell cycle contolled?

Answer 9

By checkpoints to check if the cell is viable or not at:
-G1 (end of G1 before S)
-G2 (end of G2 before mitosis).
-Spindle assembly (metaphase)- during mitosis.

Question 10

What are the 4 stages of mitosis?

Answer 10

-Prophase
-Metaphase
-Anaphase
-Telophase

Question 11

What happens in prophase?

Answer 11

-Chromosomes become more distinct (coil up and shorten) becoming visible and condensing.
-Centriole divides and moves to opposite poles of the cell.
-Nucellar envelope disintegrates.
-Nucleolus becomes more distinct.

Question 12

What happens in metaphase?

Answer 12

-Centrioles are now at opposite poles and begin to produce spindle fibres.
-Spindles attach to the centromere of the chromosomes.
-Chromosomes are pulled to the metaphase plate (equator) of the cell.

Question 13

What happens in anaphase?

Answer 13

-Spindle fibres contract which requires ATP.
-Chromatids are pulled to opposite poles of the cell.

Question 14

What happens in telophase?

Answer 14

Chromatids reach poles of the spindles.
-The chromatids begin to uncoil and become less distinct.
-Nuclear envelope begins to reform.

Question 15

What happens in cytocenisis?

Answer 15

-The cell divides.

Question 16

How does cytokinesis happen in animal cells?

Answer 16

The edges of the cell begin to constrict and makes the cytoplasm splits.

Question 17

How does cytokinesis happen in plant cells?

Answer 17

A cell wall is laid between the two cells.

Question 18

What is the equation for mitotic index?

Answer 18

Number of cells with condensed chromosomes / total number of cells

Question 19

What is the process called where cells divide in prokaryotic cells?

Answer 19

Binary fission.

Question 20

What cells divide in mitosis?

Answer 20

Eukaryotic cells.

Question 21

What is the process of binary fission?

Answer 21

-The circular and plasmid DNA duplicates.
-The cell grows.
-The cell then divides into 2, genetically identical cells when the cytoplasm splits.
-Number of plasmids vary as the number varies in the parent cell.

Question 22

What is different about mitosis and binary fission?

Answer 22

Binary fission is a lot quicker of a process than mitosis.

Question 23

When looking at mitosis through a microscope why might two students calculate different mitotic index’s?

Answer 23

-Different fields of views.
-Cells undergo cell division at different rates and times.