Carla - Introduction to the Cell Cycle Flashcards
What does the length of a cells life depend on?
The type of cell they are e.g. epithelia live for a short amount of time
How long do rbcs live for?
120 days
What is cell division?
The process by which new cells are made
What is mitosis?
Cell replication leading to division
Identical clones
Give three reasons why cells divide
Growth
Replace old cells
Replenish low numbers
What occurs when growth happens by accident?
Tumours are formed
What happens as cells age?
(3)
They get worn out
They become not as good at carrying out their function
Accidental mutations can occur
When might cells have to be replaced?
(2)
If cells have burst
If cells are damaged
What is required for cell division?
Cell signalling -> it is a very carefully regulated event
What must first be done before replication?
(4)
All the components required to make a new cell must be made
Genetic material must be copied
Identical copy of each chromosome must be made
All cell components
Explain how cell replication and division happens
(9)
Strands of DNA become more tightly packed into a condensed form
The parent and copy remain attached to each other in the one place
The membrane around the nucleus then breaks down
The chromosomes line up across the centre of the cell
The parent and copy then separate
The individual chromosomes move to opposite sides of the cell
The cell membrane begins to pinch inwards
Genetic information is enclosed in new nuclear membranes in parent and daughter
The chromosomes uncoil and turn into long threads of DNA again
How many phases are there to cell replication?
Two main phases
- interphase
- mitotic phase (M phase)
What happens in interphase?
The cell grows and makes a copy of its DNA
What happens in the mitotic phase?
The cell separates its duplicated DNA into two sets and divides its cytoplasm forming two new cells
How many stages are there to mitosis?
Five
What are the five stages to mitosis?
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
What comes before mitosis?
Interphase
How many pauses are there in the cell cycle?
Three
What are the three phases to interphase?
G1 phase
S phase
G2 phase
What is the G1 phase?
(2)
This is the cell growth phase - prep phase
Cellular contents excluding the chromosomes are duplicated
What is the S phase?
Each of the 46 chromosomes are duplicated by the cell
What is the G2 phase?
The cell double checks the duplicated chromosomes for errors and makes any necessary repairs
List in the correct order the phases of the cell cycle
Interphase (G1, S, G2 phases)
Mitosis (Prophase, Metaphase, Anaphase, Telophase, Cytokinesis)
How many chechpoints are there in the cell cycle?
Three
Name the three checkpoints of the cell cycle
G1 checkpoint
G2 checkpoint
M checkpoint
What happens at the G1 checkpoint?
(5)
The cell decides whether or not to divide
Cell checks for:
- size
- nutrients
- growth factors
- DNA damage
What happens if the cell passes the G1 checkpoint?
The cell enters the S phase
What happens if the cell doesn’t pass the G1 phase?
It enters the resting state (G0 phase)
What happens at the G2 checkpoint?
Double checks the DNA
Is there any errors - can they be fixed
If there is unfixable errors the cell does not go on to mitosis -> apoptosis
Give the four dyes used to stain cells
Green stain fluorescent -> binds actively replicating DNA (S)
Red stain fluorescent propidium iodide (PI) -> binds DNA
Yellow stain fluorescent -> binds over lapping cells
Who discovered cells could divide?
Walter flemming
