Mitosis Flashcards
What happens during the inter phase of the cell cycle?
– G1: cell growth, normal gene expression
– S: copy DNA
– G2: cell growth, duplicate organelles
What phases happen during the mitosis -phase of the cell cycle?
- “PPMAT”
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
What happens during the Cytokineses phase of the cell cycle
- 2 new cells divide
What happens during prophase?
The chromosomes condense
– Chromatin condenses into chromosomes
– Mitotic spindle fibres (complex structure consisting of micro-tubules and proteins) form and push the two centrosomes apart
What happens during prometphase?
The chromosomes attach
– Kinetochore protein complex binds to centromeres
– Nuclear envelope breaks down
– Mitotic spindles attach to kinetochores, thus linking centrosomes and chromosomes
What happens during metaphase?
Chromosomes align
– Chromosomes line up in middle of the cell, along an imaginary “metaphase plate”
What happens during anaphase?
Chromosomes separate
– Sister chromatids separate
– Chromatid pairs pulled apart along spindle fibres by motor protein
What happens during telophase?
Chromosomes relax
– Nuclear envelopes form around chromosomes
– Spindle fibres disintegrate
What happens during cytokinesis?
- Actin microfilaments form a ring on inside of cell membrane, in middle of dividing cells (at location of metaphase plate) → forms a narrow groove (“cleavage furrow”)
- Filaments are drawn together, pinching the cell membrane together → separates cytoplasm into 2 identical daughter cells
What happens during prophase in a plant cell?
The chromosomes are condensing and the nucleolus is beginning to disappear. Although not yet visible in the micrograph, the mitotic spindle is starting to form.
What happens during the prometaphase in a plant cell?
Discrete chromosomes are now visible; each consists of two aligned, identical sister chromatids. Later in prometaphase, the nuclear envelope will fragment.
What happens during metaphase in a plant cell?
The spindle is complete, and the chromosomes, attached to microtubules at their kinetochores, are all at the metaphase plate.
What happens during anaphase in a plant cell?
The chromatids of each chromosome have separated, and the daughter chromosomes are moving to the ends of the cell as their kinetochore microtubules shorten.
What happens during telophase in a plant cell?
Daughter nuclei are forming. Meanwhile, cytokinesis has started: The cell plate, which will divide the cytoplasm in two, is growing toward the perimeter of the parent cell.
How does cytokinesis work in plant cells?
In a plant cell there in a cell wall that is more brittle than a cell membrane. Therefore to separate the daughter cells there are many vesicles that form a cell plate in the middle of the two cells. Eventually these vesicles form the new cell wall.
What happens during the G1 phase of the cell cycle.
The G1 phase is the time in which a cell grows. During this phase, the cell synthesizes various enzymes and nutrients that are needed later on for DNA replication and cell division. The duration of the G1 phase is variable and it often depends on the nutrients that are available to a cell. The G1 phase is also when cells produce the most proteins.
What happens during the G2 phase of the cell cycle
During G2, the cell will continue to grow and produce new proteins. At the end of G2 is another control checkpoint (G2 Checkpoint) to determine if the cell can now proceed to enter M (mitosis) and divide.
- Preparation for mitosis
What happens during S phase of the cell cycle?
To produce two similar daughter cells, the complete DNA instructions in the cell must be duplicated. DNA replication occurs during this S (synthesis) phase.
What is the main function of M phase (mitosis)
cell division
What is the first step in animal cell mitosis?
Chromosomes duplicate to produce sister chromatids
What is the second step in animal cell mitosis?
Duplicated chromosomes condense
What is the third step in animal cell mitosis?
Duplicated chromosomes migrate to the equatorial plane of the cell and the nuclear membrane breaks down
What is the fourth step in animal cell mitosis?
Sister chromatids of each duplicated chromosome moves to opposite poles of the cell.
What is the fifth step in animal cell mitosis?
Chromosomes decondense and nuclear membranes form
