Biology - Module 5: Cell division

Interphase

Interphase

The period of the cell cycle when the cell synthesizes new organelles and molecules in preparation for mitosis.

Genome

The entire set of genetic information in an organism.

Sexual

Type of reproduction that involves fertilization and exchange of genetic information.

Somatic

Majority of cells present in the body.

Asexual

Type of reproduction that results in the production of offspring that is a clone of the single parent cell.

Telophase

Step in mitosis during which daughter nuclei appear at the two poles of the cell and the nuclear envelope reforms around the chromosomes.

Down syndrome

The condition caused by trisomy 21.

Haploid

1 set of chromosomes (1 copy of each gene).

Chromatin

Mass of long thin fibers of DNA and proteins that make up chromosomes.

Centromere

The junction where two chromatids are joined together.

Anaphase

Step in mitosis during which chromosomes are pulled apart.

Diploid

2 sets of chromosomes (2 copies of each gene).

Meiosis

Cell division that converts diploid nuclei to haploid nuclei.

Sisterchromatid

Two copies of a chromosome that are connected by a centromere.

Trisomy

Inheritance of 3 copies of a chromosome (often chromosome 21).

Nondisjunction

Failure of chromosomes or chromatids to separate during meiosis.

Cleavagefurrow

A shallow groove in the cell surface that occurs during cytokinesis in animal cells.

Metaphase 1

Phase of meiosis where homologous pairs of chromosomes (tetrads) line up along the metaphase plate and independent assortment occurs.

Polyploidy

More than two sets of chromosomes.

Prophase

Step in mitosis during which the chromatin fibers become tightly coiled into chromosomes and the nuclear envelop starts to break down.

Gametes

Sex cells of an organism such as sperm and egg.

Chromosomes

In humans, a linear strand of DNA and proteins that carries hereditary information (humans have 46 of these).

Cytokinesis

The division of the cytoplasm that takes place during telophase.

Cell cycle

An ordered sequence of events that extends from the time a cell is first formed until its own division.

Crossing over

Meiotic phase where crossing over occurs.

Binary fission

Prokaryotes use this type of cell division to reproduce

Synapsis

Exchange of genetic material in meiosis when tetrads form.

Metaphase

Step in mitosis during which chromosomes line up on the metaphase plate.

Mitosis

Division of the cell into two daughter cells that are identical.