The Cell Cycle and Cell Division
The cell cycle is a series of events during which a cell duplicates its contents and divides. This process is crucial for growth, repair, and reproduction in organisms.
Definition: The cell cycle is the sequence of events that occurs in a cell leading to its division and duplication.
The 4 stages of cell cycle include:
- G1 phase growth
- S phase synthesis
- G2 phase growth
- M phase mitosis
Highlight: Interphase, comprising G1, S, and G2 phases, is the longest part of the cell cycle, during which the cell grows, replicates DNA, and prepares for division.
During interphase, several key events occur:
- Cells grow and increase in size
- DNA replicates, producing identical sister chromatids
- Organelles duplicate
- Proteins are synthesized
The cell cycle is controlled by checkpoints that ensure the cell is ready to progress to the next phase. These checkpoints are regulated by cyclin-CDK complexes.
Vocabulary: Cyclin-CDK complexes are protein pairs that regulate the progression of the cell cycle.
Mitosis, the process of nuclear division, consists of four main stages:
- Prophase
- Metaphase
- Anaphase
- Telophase
Example: During prophase, chromosomes condense and become visible, while the nuclear envelope breaks down.
The role of centrioles in cell division is crucial. Centrioles organize fibrous proteins into the spindle, which is essential for chromosome separation during mitosis.
Highlight: Centrioles are not present in plant cells, highlighting a key difference in cell division between plant and animal cells.
