Cell Structure and Division- Mitosis

Question 1

What are the two types of cell division in eukaryotes?

Answer 1

Mitosis and meiosis

Question 2

What happens in mitosis?

Answer 2

A parent cell divides to produce two genetically identical daughter cells

Question 3

What is mitosis needed for?

Answer 3

Growth of multicellular organisms and repairing damaged tissues

Question 4

What does the cell cycle consist of?

Answer 4

A period of cell growth and DNA replication called interphase, mitosis happens after this

Question 5

What happens in G1?

Answer 5

Cell grows and new organelles and proteins are made

Question 6

What happens in S?

Answer 6

Cell replicates its DNA

Question 7

What happens in G2?

Answer 7

Cell keeps growing and proteins needed for cell division are made

Question 8

What are the three growth stages in interphase?

Answer 8

G1, S and G2

Question 9

What happens in interphase?

Answer 9

Cell’s DNA is unravelled and replicated, organelles are also replicated, ATP content is increased

Question 10

What happens in prophase?

Answer 10

• Chromosomes condense and get shorter and fatter
• Centrioles start moving to opposite ends of cell
• Form spindle
• Nuclear envelope breaks down

Question 11

What happens in metaphase?

Answer 11

• Chromosomes line up along equator of cell

- Attach to spindle by centromere

Question 12

What happens in anaphase?

Answer 12

• Centromeres divide
• Each pair of sister chromatids separate
• Spindles contract
• Chromatids pulled to opposite poles of cell
• Chromosomes appear V-shaped

Question 13

What happens in telophase?

Answer 13

• Chromosomes reach opposite poles on spindle
• Uncoil and become long and thin
• Nuclear envelope forms
• Division of cytoplasm (cytokinesis)
• Forms two daughter cells that are genetically identical

Question 14

How can you calculate how long each stage of mitosis lasts?

Answer 14

eg. 100 cells undergoing mitosis, 10 in metaphase, one complete cell cycle= 15 hours, how long do cells spend in metaphase?
10/100th of cell cycle in metaphase
15 x 60= 900 minutes
10/100 x 900= 90 minutes in metaphase

Question 15

What are mitosis and the cell cycle controlled by?

Answer 15

Genes

Question 16

How can cells grow out of control?

Answer 16

If there’s a mutation in a gene that controls cell division

Question 17

How is a tumour formed?

Answer 17

Cells keep on dividing to make more and more cells

Question 18

What is cancer?

Answer 18

A tumour that invade surrounding tissue

Question 19

What are treatments for cancer designed to do?

Answer 19

Control the rate of cell division in tumour cells by disrupting the cells cycle which kills the tumour cells

Question 20

What is the problem with cancer treatments?

Answer 20

They don’t distinguish tumour cells from normal cells so they also kill normal body cells that are dividing

Question 21

Why would cancer treatments target G1?

Answer 21

This would prevent the synthesis of enzymes needed for DNA replication and if these aren’t produced the cell can’t enter the S phase so the cell cycle is disrupted which forces the cell to kill itself

Question 22

Why would cancer treatments target the S phase?

Answer 22

This is the stage of DNA replication and the cell is checked for damage so if severe damage is detected then the cell will kill itself and prevent further tumour growth