Biology Mitosis and Meiosis Vocab

anaphase

stage of mitosis during which sister chromatids are separated from each other

binary fission

prokaryotic cell division process

cell cycle

ordered series of events involving cell growth and cell division that produces two new daughter cells

cell-cycle checkpoint

mechanism that monitors the preparedness of a eukaryotic cell to advance through the various cell-cycle stages

centriole

rod-like structure constructed of microtubules at the center of each animal cell centrosome

centromere

region at which sister chromatids are bound together; a constricted area in condensed chromosomes

chromatid

single DNA molecule of two strands of duplicated DNA and associated proteins held together at the centromere

cleavage furrow

constriction formed by an actin ring during cytokinesis in animal cells that leads to cytoplasmic division

cytokinesis

division of the cytoplasm following mitosis that forms two daughter cells.

diploid

cell, nucleus, or organism containing two sets of chromosomes (2n)

G0 phase

distinct from the G1 phase of interphase; a cell in G0 is not preparing to divide

G1 phase

(also, first gap) first phase of interphase centered on cell growth during mitosis

G2 phase

(also, second gap) third phase of interphase during which the cell undergoes final preparations for mitosis

gamete

haploid reproductive cell or sex cell (sperm, pollen grain, or egg)

gene

physical and functional unit of heredity, a sequence of DNA that codes for a protein.

haploid

cell, nucleus, or organism containing one set of chromosomes (n)

homologous chromosomes

chromosomes of the same morphology with genes in the same location; diploid organisms have pairs of homologous chromosomes (homologs), with each homolog derived from a different parent

interphase

period of the cell cycle leading up to mitosis; includes G1, S, and G2 phases (the interim period between two consecutive cell divisions)

locus

position of a gene on a chromosome

metaphase

stage of mitosis during which chromosomes are aligned at the metaphase plate

metaphase plate

equatorial plane midway between the two poles of a cell where the chromosomes align during metaphase

mitosis

(also, karyokinesis) period of the cell cycle during which the duplicated chromosomes are separated into identical nuclei; includes prophase, prometaphase, metaphase, anaphase, and telophase

spindle

apparatus composed of microtubules that orchestrates the movement of chromosomes during mitosis

oncogene

mutated version of a normal gene involved in the positive regulation of the cell cycle

prometaphase

stage of mitosis during which the nuclear membrane breaks down and mitotic spindle fibers attach to kinetochores

prophase

stage of mitosis during which chromosomes condense and the mitotic spindle begins to form

proto-oncogene

normal gene that when mutated becomes an oncogene (mutated genes that can lead to uncontrolled cell growth and the development of cancer)

S phase

second, or synthesis, stage of interphase during which DNA replication occurs

telophase

stage of mitosis during which chromosomes arrive at opposite poles, decondense, and are surrounded by a new nuclear envelope

alternation of generations

life-cycle type in which the diploid and haploid stages alternate

chiasmata

(singular, chiasma) the structure that forms at the crossover points after genetic material is exchanged

crossover

exchange of genetic material between nonsister chromatids resulting in chromosomes that incorporate genes from both parents of the organism

fertilization

union of two haploid cells from two individual organisms

Independent assortment

- Sorting of homologous chromosomes

interphaseII

brief period of rest between meiosis I and meiosis II

life cycle

the sequence of events in the development of an organism and the production of cells that produce offspring

meiosis

a nuclear division process that results in four haploid cells

meiosis I

first round of meiotic cell division; referred to as reduction division because the ploidy level is reduced from diploid to haploid

meiosis II

second round of meiotic cell division following meiosis I; sister chromatids are separated into individual chromosomes, and the result is four unique haploid cells

somatic cell

all the cells of a multicellular organism except the gametes or reproductive cells

tetrad

two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase I