Mitosis & Cell cycle

Question 1

Why do multicellular organisms need a continuous supply of new cells

Answer 1

• Growth
• Development
• Repair

Question 2

What is the cell cycle

Answer 2

• The process of duplicating a cell to form 2 identical daughter cells

Question 3

What are the 3 main stages of the cell cycle

Answer 3

• Growth & DNA replication
• Mitosis
• Cell division

Question 4

Explain stage 1 of the cell cycle

Answer 4

• Growth of sub - cellular structures (mitochondria and ribosomes)
• DNA is normally flowing in long strands. During the cell cycle, it coils up into chromosomes (23 pairs in a human).
• Each chromosome replicates, forming an identical copy of itself. The replicated chromsomes stick on to the original ones, forming an “X”. Each arm is a different chromosome

Question 5

Explain stage 2 of the cell cycle

Answer 5

• Mitosis
• The chromosomes line up in the middle of the cell
• The cell fibres pull the arms to the 2 opposite poles
• Membranes form around each set of chromosomes forming 2 nuclei

Question 6

Explain stage 3 of the cell cycle

Answer 6

• The membrane & cytoplasm split forming 2 identical daughter cells