Mitosis

Question 1

3 key stages of the cell cycle.

Answer 1

1.) Interphase
2.) Nuclear division (mitosis/ meiosis)
3.) Cytokinesis.

Question 2

What is the longest part of the cell cycle?

Answer 2

• Interphase.

Question 3

What 3 main things happen in interphase?

Answer 3

1.) Organelles replicate (ie. mitochondria/ ribosomes.)
2.) Cell grows
3.) DNA replicates

Question 4

What are the 3 different stages of interphase?

Answer 4

1.) G1
2.) S-phase
3.) G2

Question 5

What happens in G1 stage of interphase?

Answer 5

• Cell grows.
• Organelles (ie. mitochondria/ ribosomes) replicate.

Question 6

What happens in S-phase of interphase?

Answer 6

• DNA replication.

Question 7

What happens in G2 phase of interphase?

Answer 7

• Cell grows.
• Replicated DNA is checked for any potential mutations -if there are mutations - the cell will die at this stage.

Question 8

What is cytokinesis?

Answer 8

• Divison of the cytoplasm/ cell membrane to create the new cells.

Question 9

Difference between cells produced by mitosis vs meiosis.

Answer 9

• Mitosis: two genetically-identical diploid cells produced.
• Meiosis: four genetically different haploid cells produced

Question 10

Give 4 reasons why cells divide

Answer 10

1.) Increase cell number
2.) Replace cells and tissues
3.) Produce genetically- identical cells.
4.) Assexual reproduction/ cloning.

Question 11

What is meant by term “diploid cell?”

Answer 11

• Each cell has 2 copies of each chromosome.

Question 12

Give an EXAMPLE of where mitosis is important.

Answer 12

• Important in clonal expansion of B- cells.

Question 13

What is mitosis?

Answer 13

• Part of cell cycle in which eukaryotic cell divides to produce two daughter cells- each with identical copies of DNA produced by the parent cell during DNA replication.

Question 14

True or False

In all multi-cellular organisms, all cells retain the ability to divide.

Answer 14

• False.
• Not all cells retain the ability to divide.

Question 15

What are 4 key stages of mitosis?

Answer 15

Prophase
Metaphase
Anaphase
Telophase

Question 16

What are the outlines of mitosis?

Answer 16

• One round of division
• Genetically-identical cells made
• Diploid cells made

Question 17

What happens in prophase?

Answer 17

• Chromosomes condense and become visible.
• Centrioles move to opposite poles of the cell.
• Nuclear envelope breaks down.
• Chromosomes appear as two sister chromatids - joined at centromere.

Question 18

What are centrioles?

Answer 18

• Centrioles are structures responsible for creating spinle fibres.

Question 19

What happens in metaphase?

Answer 19

• The chromosomes line along the equator of the cell.
• Spindle fibres attach to centromeres.

Question 20

What is the centromere?

Answer 20

• Middle part of chromosome that holds together two sister chromatids.

Question 21

What happens in anaphase?

Answer 21

• Centromere splits
• Spindle fibres contract (separating sister chromatids), pulling/ moving sister chromatids to opposite ends/ poles of the cell.
• This stage requires ATP

Question 22

What happens in telophase?

Answer 22

• Chromosomes no longer visible (as they uncoil.)
• Nuclear envelope reforms
• Spindle fibres disintegrate.
• Cytokinesis: cytoplasm/ cell membrane splits to create two new genetically- identical cells.

Question 23

How do you calculate mitotic index?

Answer 23

• The number of cells in mitosis (in field of view)/ the total number of cells (in field of the view.)

Question 24

What type of process is mitosis?

Answer 24

• A controlled process.

Question 25

What can uncontrolled cell divison lead to the formation of?

Answer 25

• Uncontrolled cell division can lead to the formation of tumours/ cancers.

Question 26

What are many cancer treatments directed at?

Answer 26

• Many cancer treatments directed at controlling the rate of cell division.