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Biology - Unit 1 > Cell Cycle > Flashcards

Flashcards in Cell Cycle Deck (17):

What does interphase consist of?

G1, S and G2 stages


What happens during G1?

The cell makes new proteins and copies of the organelles


What happens during the S phase?

DNA replication occurs


What happens during the G2 phase?

The cell makes more proteins and copies of organelles in preparation for mitosis


What does the M phase consist of?

Mitosis and cytokinesis


What happens during Prophase?

The chromosomes condense and become visible as two joined chromatids, spindle fibres attach to centromeres, nuclear membrane disintegrates.


What happens during metaphase?

Spindle fibres move chromosomes so they line up along the metaphase plate at the equator of the cell.


What happens during anaphase?

The spindle fibres pull the sister chromatids apart


What happens during telophase?

The separated chromosomes are pulled by the spindle fibres to opposite poles to form daughter nuclei. Chromosomes uncoil and the nuclear membrane is made again.


What happens during cytokinesis?

The membrane is pulled in by part of the cytoskeleton to divide the cytoplasm to form two daughter cells.


What needs to happen before the membrane is made in plant cells?

Plant cells have to form a middle lamellae and cell wall


What is the mitotic index of a sample?

The percentage of cells undergoing mitosis


What is the purpose of the checkpoints?

The prevent progress of a cell during the cell cycle if something is incorrect


Where are the checkpoints placed?

The end of G1, the end of G2 and during metaphase


What does the G1 checkpoint monitor and control?

Monitors cell size (ensures sufficient cell mass is present to form two daughter cells) and allows the cell to continue to the S stage.


What does the G2 checkpoint monitor and control?

Monitors the success of DNA replication (ensuring the two daughter cells receive a complete copy of DNA) controls entry to mitosis using MPF


What does the M checkpoint monitor and control?

Monitors chromosome alignment, (ensuring one chromatid from each chromosome is received by each daughter cell). Controls entry to anaphase. It triggers the exit of mitosis and the start of cytokinesis.