Bio Chapter 5 Terms

Somatic Cell

body cell; excludes cells that undergo meiosis and become sperm or eggs

Apoptosis

programmed cell death; involves a cascade of specific cellular events leading to death and destrction of the cell

Cell Cycle

an ordered sequence of events in eukaryotes that involves cell growth and nuclear division; consists of the stages G1, S, G2, and M

Interphase

stages of the cell cycle (G1, S, G2) during which growth and DNA synthesis occur when the nucleus is not actively dividing

G1 Checkpoint

cell cycle main checkpoint. if DNA is damaged, apoptosis will occur. otherwise, the cell is committed to divide when growth signals are present and nutrients are available

G2 Checkpoint

mitosis checkpoint, mitosis will occur if DNA has replicated properly. apoptosis will occur if the DNA is damaged and cannot be repaired

M Checkpoint

spindle assembly checkpoint. mitosis will not continue if chromosomes are not properly aligned

Chromatid

following replication, a chromosome consists of a pair of sister chromatids, held together at the centromere; each chromatin is comprised of a single DNA helix

Sister Chromatid

one of two genetically identical chromosomal units that are the result of DNA replication and are attached to each other at the centromere

Mitosis

the stage of cellular reproduction in which nuclear division occurs; process in which a parent nucleus produces two daughter nuclei, each having the same number and kinds of chromosomes as the parent nucleus

Cytokinesis

division of the cytoplasm following mitosis or meiosis

Growth Factor

a hormone or chemical, secreted by one cell, that may stimulate or inhibit growth of another cell or cells

Proto-Oncogene

gene that promotes the cell cycle and prevents apoptosis; may become an oncogene through mutation

Tumor Suppressor Gene

gene that codes for a protein that ordinarily suppresses the cell cycle; inactivity due to a mutation can lead to a tumor