Cell Division and Fate Determination Flashcards
Name the cell division stages:
Prophase // Prometaphase // Metaphase // Anaphase // Telophase // Cytokinesis.
How many daughter cells are produced in mitosis?
2 daughter cells are produced.
In what cell division are 4 daughter cells produced?
Meiosis
Which process goes array in regards to cancer?
Mitosis
Name the stages of the cell cycle:
G0, G1, S, G2, Mitosis and Cytokinesis.
G1, S and G2 are in the interphase stage.
Which types of cells are part of the G0 stage?
If a cell can’t divide it is part of the G0 phase.
These cells are:
- Terminally differentiated.
- Senescent cells = (these are unable to grow and are permanently in G0).
Explain briefly the cell cycle stages:
G1: growth and preparation of chromosomes for replication.
S: Synthesis of DNA ( and centrosomes.)
G2: Preparation of mitosis.
M: Mitotic division of cell into two daughter cells.
G0: Growth arrest (quiescence and senescence.)
In the ‘S’ stage of the cell cycle what happens?
DNA replicates
Chromosomes double
What are Okazaki fragments?
They are nucleotide fragments which are added in the ‘S’ phase.
In the ‘G2 / M’ stage of the cell cycle what happens?
Period of rapid cell growth and protein synthesis to prepare for mitosis (M phase).
What is p53 and why is it important?
p53 is a potent suppressor gene and it’s important because it prevents cancer. (known as a tumour suppressor gene.)
What are the 3 checkpoints present in the cell cycle?
1) Cell growth checkpoint
2) DNA synthesis checkpoint
3) Mitosis checkpoint
Describe the cell growth checkpoint.
Occurs at the end of the growth phase. Checks whether the cell is big enough and has enabled the right proteins for synthesis phase.
If not - the cell goes to the G0 phase until it is ready to divide.
Describe the DNA synthesis checkpoint.
Occurs during the synthesis phase. This checks whether the DNA has been replicated correctly.
If so, the cell carries onto the mitosis phase.
Describe the mitosis checkpoint.
Occurs during the mitosis phase. This checks whether mitosis is complete.
If so, the cell divides and thus, the cell repeats.
What are cyclins?
They are a family of regulatory proteins which controls the progression of the cell cycle.
How does cyclin regulate the progression of the cell cycle?
Cyclins regulates the cell cycle by activating CDK’s (cyclin dependant kinases) via phosphorylation. The concentration of the cyclins corresponds to the different phases of the cell cycle.
How can you tell which stage the cell cycle is at?
Cyclin D: Drives the transition between G1 and S stage.
Cyclin E: Inhibits Cyclin D activity.
Cyclin A: Controls DNA copying.
Cyclin B: Drives the transition between G2 and M stage.
Why does cyclin degradation terminate CDK activity?
If there is no cyclin present to bind: the CDK is not required and therefore the CDK activity ceases to exist.
What are cyclin - dependent kinase inhibitor proteins normally used for?
Tumour suppressors.
What does the G0 phase allow to happen?
Enables cells to undergo phenotypical changes. (IE: Become a new type of cell.)
What key properties do stem cells have?
1) Potency = Can differentiate into specialist cell types.
2) Self - Renewal = Can continuously divide and replicate.
What leads to the loss of pluripotency?
Specialisation of cells.
Name the different types of stem cells:
Totipotent // Pluripotent // Multipotent // Unipotent
