Coined in German, from Greek "khroma," meaning "color." Why? Because they are easily stained by certain dyes.
A threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
Each chromosome consists of two of these identical parts.
Each of the two threadlike strands into which a chromosome divides longitudinally during cell division.
Euchromatin (aka. chromatin)
Chromosome material that does not stain strongly except during cell division.
Chromosome material of greater density from normal, in which the activity of the genes is modified or suppressed; the form DNA takes when a cell is dividing.
Chromatids are attached here.
The point on a chromosome by which it is attached to a spindle fiber during cell division.
Another term for centromere.
Chromosomal attachment point for the spindle fibers located within the centromeres.
These separate during mitosis and help to organize the spindle.
A minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.
Spindle (Spindle Fibers)
A slender mass of microtubules formed when a cell divides. At metaphase, the chromosomes become attached to it by their centromeres before being pulled toward its ends.
Microtubule structure that helps separate the chromosomes.
An organelle near the nucleus of a cell that contains the centrioles (in animal cells) and from which the spindle fibers develop in cell division.
The resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis.
A type of cell division that results in two daughter cells each with HALF the chromosome number of the parent cell, as in the production of gametes.
The first stage of cell division during which the chromosomes become visible as paired chromatids and the nuclear envelope disappears.
The second stage of cell division during which the chromosomes become attached to the spindle fibers. Chromosomes align along the metaphase plate.
The stage of cell division in which the chromosomes move away from one another to opposite poles of the spindle.
The final phase of cell division in which the chromatids or chromosomes move to opposite ends of the cell and two new nuclei are formed.
Number of chromosome pairs in a normal human body cell (somatic cell) AFTER synthesis phase in interphase.
Growth Phase 1 (G1 or Gap 1)
During this phase, the normal activities of the cell, which were slowed down during M phase, resume at a high rate.
Growth Phase 2 (G2 or Gap 2)
This phase lasts until the cell enters mitosis. Significant biosynthesis occurs during this phase. This involves the production of microtubules, and general growth of the cell.
Synthesis Phase (S)
Phase when DNA synthesis begins. When it is complete, all of the chromosomes have been replicated.