Chapter 9: The Cell Cycle

Cell division:

The continuity of life is based on the reproduction of cells

Cell cycle:

the life of a cell from its formation to its own division

Chromatin:

a complex of DNA and protein

Somatic cells:

(nonreproductive cells) of humans, have 46 chromosomes, 2 sets of 23

Gametes:

(reproductive cells; sperm and eggs) have half as many chromosomes as somatic cells, 23 chromosomes in the case of humans

Sister chromatids:

joined copies of the orginal chromosome

Centromere:

where the two chromatids are most closely attached

Mitosis:

the division of the genetic material in the nucleus

Cytokinesis:

the division of the cytoplasm

Meiosis:

yields nonidentical daughter cells that have only one set of chromosomes, half as many as the parent cell.

The cell cycle consists of:

Mitotic (M) Phase and Interphase

Mitotic (M) Phase:

including mitosis and cytokinesis

Interphase:

including cell growth and copying of chromosomes in preparation for cell division

Mitotic spindle:

a structure made of microtubes and associated proteins

Centrosome:

a type of microtubule organizing center

Aster:

a radial array of short microtubules

Kinetochores:

protein complexes that assemble on sections of DNA at centromeres

Metaphase plate:

an imaginary structure at the midway point between the spindle’s two polet

Cleavage:

In animals, cytokinesis occurs by this process

Cleavage furrow:

a shallow groove in the cell surface

Cell plate:

forms during cytokinesis

Binary Fission:

a type of cell division where prokaryotic cells (bacteria and archaea) reproduce.

In bacteria, the single chromosome replicates, beginning at the:

Origin of replication

The sequential events of the cell cycle are directed by a distinct __________, which is similar to a control device of a washing machine

cell cycle control system

The clock has specific _________ where the cell cycle stops until a go-ahead signal is received

checkpoints

If the cell does not receive the go-ahead signal, it will exit the cycle, switching into a nondividing state called the ______.

G0 phase

Growth factors:

proteins released by certain cells that stimulate other cells to divide

Density-dependent inhibition:

crowded cells stop dividing

anchorage dependence:

animal cells being attached to something in order to divide (inside of a culture flask or the extracellular matrix of tissue).

Cells in culture that can divide indefinitely are said to have undergone a process called:

transformation

If abnormal cells remain only at the original site, the lump is called a _______

benign tumor

Malignant tumors:

invade surrounding tissues and undergo metastasis

Metastasis:

exporting cancer cells to other parts of the body, where they may form additional tumors

Prophase:

Chromosomes condense and become clearly visible within the nuclear envelope.

Prometaphase:

the chromosomes convene at the metaphase plate

Anaphase:

begins when the paired centrosomes of each chromosome separates; the sister chromatids are moved to the poles

Telaphase:

two daughter nuclei form and the chromosomes become less tightly coiled; cytokinesis begins during this phase, resulting in two identical daughter cells