The cell cycle

Question 1

What is the Cell Cycle

Answer 1

The Cell Cycle is a Series of Events the Cell Carries Out in Preparation for the Cell Division

Question 2

What are the stages of the cell cycle? (5)

Answer 2

1. Gap 0 phase
2. Gap 1 phase (G1)
3. Synthesis phase (S)
4. Gap 2 phase (G2)
5. Mitosis (M)

Question 3

Where are the checkpoints in the cell cycle (4)

Answer 3

1. End of G1 phase
2. Middle of S phase
3. End of G2 phase
4. Beginning of the M phase

Question 4

What happens in the Gap 1 Phase of the cell cycle (6)

Answer 4

1. preparation for DNA synthesis and cell division
2. Proteins bind to the DNA - (Origin recognition complexes (ORC’s) bind to the origin of replication sites)
3. RNA and protein are synthesised and ready for cell division
4. The cell grows to full size
5. A cell may leave the cell cycle into (G0) temporarily or permanently
6. Cells may enter the cell cycle from (G0) to (G1)

Question 5

What happens in the synthesis phase of the cell cycle (4)

Answer 5

1. Duplication of DNA
2. Proteins involved in DNA synthesis are switched on, allowing DNA replication to occur
3. Nuclear proteins (called histones) must also be produced (doubled). These proteins are needed to support the structure of the new DNA
4. A structure called a ‘centrosome’ that supports microtubules in the cell is also duplicated

Question 6

What happens in the Gap 2 phase of the cell cycle (3)

Answer 6

1. preparation for M phase, organelle replication
2. Organelle replication
3. Towards the end of the G2 Phase, the DNA condenses to look more like ‘textbook’ chromosomes.

Question 7

What happens in the Mitosis phase of the cell cycle (6)

Answer 7

1. Prophase (early Prophase) - spindle poles are formed at different sides of the cell.
2. Pro-metaphase (late Prophase) - Spindles pull chromatids to separate sides
3. Metaphase
4. Anaphase
5. Telophase
6. Cytokinesis

Question 8

What happens in the G0 phase (3)

Answer 8

1. resting phase
2. neither dividing or preparing to
3. cell performs normal functions

Question 9

How do you remember the stages of the cell cycle

Answer 9

G0 - resting
G1 - prep, ORC, growth, RNA & protein
S - duplication, formation & SWITCH on
G2 - organelles & chromosomes