Chapter 4: The Cell Cycle Flashcards
What is the purpose of cell replication?
It is essential for growth, repair and maintenance, and reproduction.
What is binary fission?
Binary fission is the method of reproduction bacteria use.
How does binary fission occur?
Its similar to mitosis as it is cell division but they have different purposes.
What is the purpose of binary fission in comparison to mitosis?
Binary fission is a way for bacteria to reproduce and increase population whereas mitosis is to replace old, worn-out cells and to increase the size of an organism.
Cytokinesis definition
Cytokinesis is when the cells enlarges in preparation for the division to be able to survive.
What does mitosis do?
Mitosis ensures that each cell is an exact replicate (daughter cell) prior to cytoplasmic division (cytokinesis).
What is the stage in between nuclear divisions (M)?
Interphase
What are the periods in interphase?
Active Growth (G1)
Synthesis of DNA (S)
Preparation for the next division (G2)
Order of periods in Interphase
G1, S, G2, M
What is G0?
G0 is an extended G1 phase which occurs in cells that have reached maturity and no longer need to replicate. This usually occurs in specialised cells.
G1 phase
The cell produces proteins, grows and carries out its usual tasks for the body
S phase
Exact duplicates of DNA are formed
G2 phase
Preparation for cell division
M phase
The cell divides into two daughter cells (mitosis)
What are the 4 stages of mitosis?
Prophase
Metaphase
Anaphase
Telophase
Prophase
Prophase is considered to be the first true stage of the mitotic process.
- The chromatin threads condense and become a visible pair of chromatids held together by the centromere.
- Centrioles then move to either end of the cell and microtubules begin to radiate from them.
- This then begins to form the framework for fibres as the nuclear membrane breaks down.