mitosis

Question 1

what is the purpose of mitosis?

Answer 1

produces 2 genetically identical daughter cells for:
- growth
- cell replacement / tissue repair
- asexual reproductions

Question 2

name the stages of mitosis

Answer 2

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Question 3

outline what happens during prophase

Answer 3

1. chromosomes condense, becoming visible (X-shaped: 2 sister chromatids joined at centromere)
2. centrioles move to opposite poles of cell (animal cells) and mitotic spindles form
3. nuclear envelope and nucleolus break down = chromosomes free in cytoplasm

Question 4

outline what happens during metaphase

Answer 4

sister chromatids line up at cell equator, attached to the mitotic spindle by their centromeres

Question 5

outline what happens during anaphase

Answer 5

1. spindle fibres contract = centromeres divide
2. sister chromatids separate into 2 distinct chromosomes and are pulled to opposite poles of the cell (looks like ‘V’ shapes facing each other)
3. spindle fibres break down
   - whole process requires energy from ATP hydrolysis

Question 6

outline what happens during telophase

Answer 6

1. chromosomes decondense, becoming invisible again
2. new nuclear envelopes form around each set of chromosomes = 2 new nuclei, each with 1 copy of each chromosome

Question 7

what happens during cytokinesis?

Answer 7

1. cell membrane cleavage furrow forms
2. contractile division of cytoplasm