The Cell Cycle and Mitosis
You can now identify the main components, explain the mechanism step by step, interpret an observation and distinguish related ideas.
Big idea
During G1 a cell grows, during S phase DNA is replicated, and during G2 the cell prepares for division. Checkpoints monitor size, DNA integrity, replication and chromosome attachment before progression.
Learning goals
- Interphase: During G1 a cell grows, during S phase DNA is replicated, and during G2 the cell prepares for division.
- Cell-cycle checkpoints: Checkpoints monitor size, DNA integrity, replication and chromosome attachment before progression.
- Mitosis: Prophase, metaphase, anaphase and telophase distribute duplicated chromosomes into two nuclei.
- Cytokinesis: Cytokinesis divides the cytoplasm after nuclear division, producing two daughter cells.
- Growth control: Regulatory proteins and external signals coordinate division; failures can lead to uncontrolled proliferation.
Core concepts
1. Interphase
During G1 a cell grows, during S phase DNA is replicated, and during G2 the cell prepares for division.
Observation: A cell doubles its DNA before chromosomes are separated.
2. Cell-cycle checkpoints
Checkpoints monitor size, DNA integrity, replication and chromosome attachment before progression.
Observation: A cell with damaged DNA pauses for repair rather than entering mitosis immediately.
3. Mitosis
Prophase, metaphase, anaphase and telophase distribute duplicated chromosomes into two nuclei.
Observation: Sister chromatids separate to opposite poles during anaphase.