cell cycle

What 2 phases are in the cell cycle

Interphase

Mitotic

What is the longest stage

Interphase

NOT A STAGE IN MITOSIS

What could interphase be referred to? And why is it not right to refer that

Resting phase

Not accurate as interphase is a very active phase

It prepares for division whilst also carrying out major functions (e.g producing enzymes)

What are the 4 phases in the celll cycle

Where dos dna duplicate?

Where do organelles replicate?

Where does protein synthesis occur?

Where would chloroplasts grow and divide?

Where does cytokinesis take place?

G1

• protein synthesis in cytoplasm

• Organelles replicate

• Cell increases in size

S

synthesis phase where dna is repplicated in nucleus*

G2

• cell increases more inside

Choloroplasts grow and divide in plants

Mitochondria grow and divide

• energy stores increase

• DUPLICATED DNA is checked for errors

MITOTIC

cell division

Mitosis nucleus divides

Cytokinesis (cytoplasm divides and 2 cells are produced)

What is the G0 phase and where does that happen?

Cell leaves cycle temporarily/ permanently

It could happen at the G1 checkpoint where if it doesn’t meet the criteria (no DNA damage or cell size increase or right amount of nutrients) then it enters G0

What are the different conditions where something goes into G0

Differentiation

a differentiated cell is no longer able to divide= permanent

Damage to DNA

can no longe divide so it enters permanent arrest

(The majority of normal cells can only divide a certain number of times before it becomes old)

AGE

increases number of senescent cells

It can be a cause of age related diseases such a cancer

What are examples of cells that temporarily go intoG0

Lymphocytes in an immune response

Why are checkpoints crucial?

Vital that a cell only divides when DNA is replicated correctly

Chromosomes are in correct positions

It ensures the accuracy and effectiveness of cell division

What happens at g1 checkpoint

Correct cell size

Check if DNA is damaged

Check if there is enough nutrients

If not it gets into g0

What are all the checkpoints and what is checked on each of them

Spindle assembly

This is the METAPHASE CHECKPOINT

Check if chromosomes are attached to the spindle

Mitosis cant happen without this

G2 checks for

• cell size

• DNA replication

• DNA damage

If passed it moves onto mitosis