Topic 1.6 - Stages of mitosis

Question 1

What is the first stage of mitosis ?

Answer 1

Interphase

Question 2

What are the key events in interphase ?

Answer 2

DNA is uncondensed (chromatin)
DNA is replicated (S phase) to form
genetically identical sister chromatids
Cell grows in size and organelles are
duplicated (G1 and G2)

Question 3

What is the second phase of mitosis ?

Answer 3

Prophase

Question 4

What are the key events in prophase ?

Answer 4

DNA supercoils and condenses
(forms visible chromosomes)
Nuclear membrane dissolves
Centrosomes move to poles and
begin to produce spindle fibres

Question 5

What is the third stage of mitosis ?

Answer 5

Metaphase

Question 6

What are the key events in metaphase ?

Answer 6

Centrosome spindle fibres attach to
the centromere of each chromosome
Spindle fibres contract and move the
chromosomes towards the cell centre
Chromosomes form a line along the
equator (middle) of the cell

Question 7

What is the fourth stage of mitosis ?

Answer 7

Anaphase

Question 8

What are the key events in anaphase ?

Answer 8

Spindle fibres continue to contract
Sister chromatids separate and move
to opposite sides of the cell
Sister chromatids are now regarded as
two separate chromosomes

Question 9

What is the fifth stage of mitosis ?

Answer 9

Telophase

Question 10

What are the key events in telophase ?

Answer 10

Chromosomes decondense
(DNA forms chromatin)
Nuclear membranes form around the
two identical chromosome sets
Cytokinesis occurs concurrently

Question 11

What is the last stage of mitosis ?

Answer 11

Cytokinesis

Question 12

What are the key events in cytokinesis ?

Answer 12

Cytoplasmic division occurs to divide
the cell into two daughter cells
Each daughter cell contains one copy
of each identical sister chromatid
Daughter cells are genetically identical