Cells (CELL CYCLE)

Question 1

What are the three stages in the cell cycle

Answer 1

Interphase
Mitosis
Cytokinesis

Question 2

What are the 4 stages within mitosis

Answer 2

Prophase
Metaphase
Anaphase
Telophase

Question 3

Describe what happens in the interphase

Answer 3

Organelles divide
DNA is replicated during the S stage

Question 4

Describe the first stage of mitosis - prophase

Answer 4

Chromosomes condense and shorten and become visible
Cells are arranged randomly as there is no spindle activity
Nuclear envelope and nucleolus disintegrate and disappear

Question 5

Describe the structure of a chromosome

Answer 5

A chromosome is made up of 2 sister chromatids joined at a centromere

Question 6

Describe the second stage of mitosis - metaphase

Answer 6

Chromosomes align along the equator of animal cell
Spindle fibres attach to the centromeres

Question 7

Describe the third stage of mitosis - anaphase

Answer 7

Centromeres are then pulled to opposite poles of the cell, seperating the chromatids. - refer to as chromosomes - now look like a v shape

Question 8

What does the anaphase require

Answer 8

ATP

Question 9

Describe the fourth stage of mitosis - telophase

Answer 9

Chromosomes are now at each pole and uncoil becoming longer and thinner and not visible
Spindle fibres breaks down
Nuclear envelope and nucleolus reforms

Question 10

Describe cytokinesis

Answer 10

The cytoplasm divides to form 2 genetically identical diploid cells

Question 11

Give the equation to work out how many cells are going through mitosis at a given moment (mitotic index)

Answer 11

number of cells in mitosis / total number of cells
x 100
–> look to see if chromosomes are visible. If so, the cell is going through mitosis

Question 12

Mitosis maintains….

Answer 12

genetic stability

Question 13

Where does mitosis occur in a plant and why should you squash this part of the plant when making a slide

Answer 13

Root tip
Squash to allow light through