Cell cycle Flashcards
What is the cell cycle (simple) ?
-It starts with a parent cell and ends with 2 genetically identical daughter cells
What are the uses of cell cycle?
-Growth,repair and replacement of cells in tissues of multicellular organisms.
- Also essential for asexual reproduction in plants,fungi, some animals and single celled organisms.
What stage does a cell spend most of its time in?
- interphase
In what stage does the DNA replicate?
- s phase
How can you tell that a chromosome has been replicated ?
- Looks like and X / has a copy of itself attached
In what stage does the nucleus divide?
- Mitosis
In what stage does the cell divide?
- cytokinesis
What stage are specialised (differentiated cells) in?
- G0 - cells have left the cell cycle
Draw and explain the cell cycle on your whiteboard
check on google did you get it right ?
What metabolic functions occur during interphase ?
In addition to normal metabolic functions:
- DNA replication
- Checking that replication is accurate
- Production of new organelles
- Cells increase in size
-** Protein synthesis**
- ATP production increases
-
What happens in G1 first growth phase?
- Transcription / translation / Protein synthesis occurs
- Organelles duplicate
- Cell grows in size.
- G1 checkpoint:
- The cell checks that the chemicals needed for replication are present and it checks for any damage to the DNA before entering S phase
What is G0 phase ?
A resting phase can be triggered in early G1
- Cells which enter this phase do not go on to replicate.
- Cells in G0 may:
- Differentiate and become specialised
- Undergo programmed cell death (apoptosis)
- Become senescent (have completed the maximum number of cell divisions)
What takes place in the S phase ?
**S: Synthesis phase: **
-DNA is replicated
-During DNA replication DNA polymerase makes many random and spontaneous errors resulting in mutations to DNA
-These can be beneficial, neutral or harmful
What takes place in G2 ?
-Cell grows in size
-ATP production increases
-Protein synthesis for spindle fibres for mitosis.
G2 checkpoint:
-The cell checks whether all the DNA has been replicated without any damage. If it has the cell can enter mitosis
PMAT - pretty mary aint tall
What are the stages of mitosis and what is it?
- Prophase
- Metaphase
- Anaphase
- Telophase
- mitosis is a form of cell division that produces identical cells, there are four
stages of mitosis: prophase, metaphase, anaphase and telophase.
What happens in prophase ?
- Chromosomes condense and become visible
- Nuclear envelope breaks down
- Nucleolus breaks up and disappears
-Centrioles migrate to opposite poles - Mitotic spindle starts to form.
What happens in the metaphase
- Chromosomes (each with two chromotids) are organised into a plane across the centre of the cell.
- Spindles fibres attach onto the centrometres.
- Metaphase checkpoint - the cell checks all the chromosomes are attached to spindle fibres.
What happens in the anaphase ?
- spindle fibres contract and the centrometres divide
- This pulls the sister chromotids to opposite poles
- Cells starts to elongate
What happens in the telophase ?
- chromosomes no longer visible
- nuclear envelope and nucleolous reforms
- spindle disintergrates
What is cytokinesis ?
- during cytokinesis the parent and replicated organelles move toopposite sides of the cell and the cytoplasm divides thus producing two daughter
cells
What are the types of cytokinesis ?
- Animal cell
- Plant cell
What happens in animal cell cytokinesis ?
- The contractile ring (containing microfilaments made up of actin) forms inbetween 2 daughter cells - needs ATP
- Cell surface membrane + cytoplasm divide
- Really quick process
What happens in a plant cell during cytokinesis ?
- A new cell wall forms inbetween two daughter cells
- Vesicles containing cell wall components start to arrange themselves at the centre of the cell
- Eventually vesicles fuse forming the new cell wall
