Unit 5- Mitosis and the Cell Cycle

cell cycle

series of events in which a cell grows, prepares for division, and divides to form two daughter cells

G1 phase

stage of interphase in which cell grows and performs its normal functions

S phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

G2

Final preparation phase. Cell checks for DNA errors and begins to form centrosomes. (Prepares for Mitosis)

Stages of Mitosis

prophase, metaphase, anaphase, telophase

Cytokinesis

division of the cytoplasm.

cleavage furrow

The area of the cell membrane that pinches in and eventually separates the dividing cell

Cancer

A disease in which some body cells grow and divide uncontrollably, damaging the parts of the body around them.

Chromosomes

threadlike structures made of DNA molecules that contain the genes

Chromatid

one of two identical "sister" parts of a duplicated chromosome

centromere

Area where the chromatids of a chromosome are attached

Interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases

Histones

protein molecules around which DNA is tightly coiled in chromatin

daughter cells

The cells that are produced as a result of mitosis. These cells are identical to each other, and also to the original parent cell.

cell plate

In a plant cell, midline of dividing cells. Becomes the cell wall eventually.

metastasis

spread of cancer cells beyond their original site in the body

Nucleosome

a structural unit of a eukaryotic chromosome, consisting of a length of DNA coiled around a core of histones.

Cell surface area to volume ratio

As a cell's size increases, its volume increases much more rapidly than its surface area

Chromatin

granular material visible within the nucleus; consists of DNA tightly coiled around proteins

Prophase

Chromosomes become visable, nuclear envelop dissolves, spindle forms

Metaphase

Chromosomes line up in the middle of the cell

Anaphase

Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell

Telophase

After the chromosome separates, the cell seals off, Final Phase of Mitosis.

Carcinogen

A cancer-causing substance

Cell division rates

these lengths of time vary depending on the cell's purpose. Skin cells divide to replace old cells every 1-2 weeks. Cells of the GI tract are replaced almost daily.

somatic cells

Any cells in the body other than reproductive cells

cell cycle checkpoints

mechanisms that monitor the preparedness of a eukaryotic cell to advance through the various cell cycle stages

Apoptosis

process of programmed cell death