BIOL 207 Lecture 4 - Cell Division, Cell Cycle, Mitosis, Meiosis (Terms)

Binary Fission

Cell division used by bacteria, archaea, and mitochondria of certain protists in which FtsZ proteins separates a cell into two daughter cells

FtsZ

A tubulin-like protein that forms a ring in binary fission in order to split the bacterial cell

Cell Cycle

The stages by which eukaryotic cells exist and divide, comprised of DNA synthesis, mitosis, and gap phases

Mitosis

Phase of the cell cycle where nuclear division occurs, resulting in two matching daughter nuclei

Interphase

The combined phases of the cell cycle in which the cell is not dividing, including G1, S, and G2

Chromatin

Decondensed chromosomes that are found in the nucleus during interphase as strand-like molecules

Nucleolus

The non-membrane bound suborganelle found within the nucleus responsible for rRNA production and ribosomal assembly

Nuclear Pore

A hole-like structure in the nuclear membrane that allows entry and exit of macromolecules into the nucleus

Histone

A protein that forms an octamer to make up the core of chromatin and chromosomes in the nucleus

Nucleosome

The basic structural unit of DNA packaging, consisting of a segment of DNA wound around a core of eight histone proteins, making up longer fibres of chromatin

Chromatin

The decondensed genetic material found in the nucleus during interphase made up of nucleosomes coiled into 30 nm fibres

Chromosomes

The condensed genetic material found in the nucleus during mitosis made up of chromatin fibres coiled into radial loops and folded into X shapes, 700 nm in diameter

Cohesin

A ring-like protein that holds sister chromatids together starting in the S phase

Centromeres

Specialized DNA regions of a chromosome that allow the connection of microtubules to the DNA via kinetochore binding

Kinetochore

A series of proteins that assemble directly onto the centromere of a chromosome, forming a docking platform for the mitotic spindle

Microtubules

Polymers of tubulin protein that attach to the centromere to pull sister chromatids apart during anaphase

Mitotic Spindle

The collection of microtubules that attach to the kinetochore on a chromosome in order to move and split the chromosomes

Microtubule Organizing Centres (MTOCs)

Spindle poles found on either side of the cell that produce the microtubules that make up the mitotic spindles

Centrosome

The MTOCs of animal/eukaryotic cells that produce the microtubules used in mitosis

Centriole

Barrel-shaped organelles made of tubulin that help form the mitotic spindle at the centrosome

Pericentriolar Matrix (PCM)

A dense mass of proteins that surrounds the centriole at the centrosome to help build and anchor microtubules

Condensin

A ring shaped protein that compacts sister chromatids closely together starting in prophase

Meiosis

The prerequisitory process to sexual reproduction that reduces chromosome content in parental cells by 50% to form haploid gametes

Zygote

A fertilized offspring cell formed from the unification of two genetically different haploid cells

Gametocyte

Diploid precursor cells that will undergo meiosis to become haploid gamete cells

Independent Assortment

A chromosome’s ability to be divided into a daughter cell independently of other chromosomes due to lining up in random order on the metaphase plate

Crossing Over

The exchange of genetic material between non-sister chromatids when they pair up in prophase I

Chiasma

X-shaped point of contact made by homologous chromosomes as they cross over