Chapter 17 - Cell Reproduction

What are the 3 major phases of the cell cycle

What are the 3 major phases of the cell cycle

Interphase

Mitosis

Cytokinesis

How long is the interphase in the cell cycle

about 20 hours

How long is the mitosis and cytokinesis phase on the cell cycle

about 4 hours

What happens in interphase

DNA is copied and the cell gets ready to divide

During what stage of interphase is DNA copied?

the S phase (synthesis)

What happens in mitosis

The nucleus is split and cytokinesis begins

What happens in cytokinesis

division of cytoplasm and the rest of the cell

What are the four stages of Mitosis

Prophase, metaphase, anaphase, telophase

What happens in the prophase stage of mitosis

DNA condenses and the nuclear membrane breaks down

What happens during the metaphase stage in mitosis

the chromosomes line up in order to be separated - moved by cytoskeletal elements

What happens during the anaphase stage in mitosis

the cytoskeletal elements pull apart the duplicated chromosomes

What happens during the telophase stage in mitosis

the nuclear membrane begins to reform and cytokinesis begins

What stage of mitosis is this cell in

Prophase

What stage of mitosis is this cell in

Metaphase

What stage of mitosis is this cell in

Anaphase

What stage of mitosis is this cell in

Telophase and cytokinesis

Functions of cell reproductions (mitosis with cytokinesis) in humans

Repair and replacement of cells (repairing a cut or replacing cells that have shed)

Reasons why cells may divide differently

Period of life you’re in (ex. sperm cells develop during puberty)

Type of cell (ex. muscle cells can have several nuclei)

What does a cell that has undergone mitosis but not cytokinesis look like?

How is the cell cycle regulated?

With 3 checkpoints checking to see that everything is in the right place before the cycle continues

What two groups of genes regulate the cell?

Proto-oncogenes → stimulate cell division

Tumor suppressor genes→ suppress cell division and detect/repair damaged DNA

How do normal cells behave

respond to growth signals

limited cell division

undergo cell death if old or damaged

stay localized

Apoptosis

Cell death / Cell suicide

How do normal cells control DNA damage?

they detect DNA damage and repair it or they activate cell death

What role do Lysomes play in cell death

they release a digestive enzyme which breaks down the damaged cells