Mitosis

Question 1

Define mitosis

Answer 1

A form of nuclear division in which one nucleus divides to form two nuclei

Question 2

Mitosis takes place in what type of cells?

Answer 2

Cells not associated with the reproductive system called somatic cells

Question 3

What are somatic cells?

Answer 3

Cells not associated with the reproductive system

Question 4

How many stages are there in mitosis?

Answer 4

There are four stages

Question 5

What are the four stages of mitosis?

Answer 5

Prophase
Metaphase
Anaphase
Telophase

Question 6

What is the mnemonic for remembering the stages of mitosis?

Answer 6

Party
Monday
And
Tuesday

Question 7

What are the five steps in prophase?

Answer 7

1. Chromatin starts to contract
2. Chromosomes become visible as double-stranded structures held together by a centromere
3. The nucleolus disappears
4. Spindle fibres appear in the cytoplasm
5. Nuclear membrane starts to break down

Question 8

Define a centromere

Answer 8

The point at which the chromosomes are attached in a double-stranded chromosome

Question 9

What is a nucleolus?

Answer 9

The region in the nucleus where ribosomes are made

Question 10

What are spindle fibres collectively called?

Answer 10

A spindle

Question 11

What starts to contract during prophase?

Answer 11

Chromatin

Question 12

What starts to break down during prophase?

Answer 12

The nuclear membrane

Question 13

What disappears during prophase?

Answer 13

The nucleolus

Question 14

What are the three steps in metaphase?

Answer 14

1. The nuclear membrane completes its breakdown
2. A spindle fibre from each end/pole of the cell attaches to each centromere
3. The chromosomes line up across the middle/equator of the cell

Question 15

What completes its breakdown during metaphase?

Answer 15

The nuclear membrane

Question 16

What attached to each centromere during metaphase?

Answer 16

A spindle fibre from each end/pole of the cell

Question 17

What is each end of a cell where spindle fibres connect to centromeres from called?

Answer 17

Poles

Question 18

What do spindle fibres from each pole of a cell connect to during metaphase?

Answer 18

Centromeres

Question 19

What do chromosomes line up across in a cell during metaphase?

Answer 19

The middle/equator of the cell

Question 20

What lines up across the middle/equator of the cell during metaphase?

Answer 20

Chromosomes

Question 21

What are the five steps of anaphase?

Answer 21

1. The spindle fibres contract causing the centromeres to split
2. One strand/chromosome from each double-stranded chromosome is pulled to opposite poles of the cell.
3. This means the cell has eight chromosomes at this stage.
4. The four chromosomes pulled to each pole have identical genes
5. Anaphase is the shortest phase in mitosis. It often lasts only a few minutes, compared with up to 30 minutes for each of the other phases

Question 22

What causes the centromeres to split during anaphase?

Answer 22

The contracting of the spindle fibres

Question 23

What pulls one chromosome from each double-stranded chromosome to opposite poles of the cell?

Answer 23

Spindle fibres

Question 24

What is the function of the spindle fibres in anaphase?

Answer 24

They split the centromeres
They pull the chromosomes to opposite poles of the cell

Question 25

How many chromosomes does a cell have during anaphase?

Answer 25

Eight chromosomes

Question 26

How many chromosomes are pulled to each pole during anaphase?

Answer 26

The four chromosomes

Question 27

What type of genes do the four chromosomes pulled to each pole of a cell during anaphase have?

Answer 27

The four genes at each pole have identical genes

Question 28

What is the shortest stage of mitosis?

Answer 28

Anaphase

Question 29

How long does anaphase last?

Answer 29

A few minutes

Question 30

How long do the phases of mitosis last (excluding anaphase)?

Answer 30

Up to 30 minutes

Question 31

What are the five steps to telophase?

Answer 31

1. The four chromosomes at each pole begin to lengthen and become hard to distinguish (chromatin) 2. The spindle fibres break down 3. One or more nucleoli begin to re-form 4. A nuclear membrane forms around the chromatin at each end of the cell 5. At the end of mitosis the original nucleus has divided into two identical nuclei

Question 32

During telophase, what happens to the four chromosomes at each pole?

Answer 32

They lengthen and become hard to distinguish

Question 33

During telophase, what elongates and becomes hard to distinguish?

Answer 33

Chromosomes

Question 34

During telophase, what breaks down?

Answer 34

The spindle fibres

Question 35

During telophase, what re-forms?

Answer 35

One or more nucleoli

Question 36

During telophase, what forms around the chromatin at the end of the cell?

Answer 36

A nuclear membrane forms

Question 37

During telophase, what does the nuclear membrane form around?

Answer 37

Chromatin at each end of the cell

Question 38

During the final step of telophase, what has the original nucleus divided into?

Answer 38

Two identical nuclei