AP Bio: Cellular Reproduction

gamete

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

cell cycle checkpoint

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

S phase

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

tumor suppressor gene

segment of DNA that codes for regulator proteins that prevent the cell from undergoing uncontrolled division

origin

(also, ORI) region of the prokaryotic chromosome where replication begins (origin of replication)

G1 phase

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

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

G2 phase

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

mitotic spindle

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

p21

cell cycle regulatory protein that inhibits the cell cycle; its levels are controlled by p53

p53

cell cycle regulatory protein that regulates cell growth and monitors DNA damage; it halts the progression of the cell cycle in cases of DNA damage and may induce apoptosis

haploid

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

diploid

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

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

cleavage furrow

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

G0 phase

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

cytokinesis

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

metaphase plate

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

karyokinesis

mitotic nuclear division

oncogene

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

proto-oncogene

normal gene that when mutated becomes an oncogene

cyclin-dependent kinase

one of a group of protein kinases that helps to regulate the cell cycle when bound to cyclin; it functions to phosphorylate other proteins that are either activated or inactivated by phosphorylation

cyclin

one of a group of proteins that act in conjunction with cyclin-dependent kinases to help regulate the cell cycle by phosphorylating key proteins; the concentrations of cyclins fluctuate throughout the cell cycle

histone

one of several similar, highly conserved, low molecular weight, basic proteins found in the chromatin of all eukaryotic cells; associates with DNA to form nucleosomes

cell cycle

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

mitotic phase

period of the cell cycle during which duplicated chromosomes are distributed into two nuclei and cytoplasmic contents are divided; includes karyokinesis (mitosis) and cytokinesis

interphase

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

gene

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

locus

position of a gene on a chromosome

binary fission

prokaryotic cell division process

kinetochore

protein structure associated with the centromere of each sister chromatid that attracts and binds spindle microtubules during prometaphase

condensin

proteins that help sister chromatids coil during prophase

quiescent

refers to a cell that is performing normal cell functions and has not initiated preparations for cell division

centromere

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

retinoblastoma protein (Rb)

regulatory molecule that exhibits negative effects on the cell cycle by interacting with a transcription factor (E2F)

centriole

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

chromatid

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

metaphase

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

telophase

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

prophase

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

anaphase

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

genome

total genetic information of a cell or organism

prometaphase

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

cell plate

structure formed during plant cell cytokinesis by Golgi vesicles, forming a temporary structure (phragmoplast) and fusing at the metaphase plate; ultimately leads to the formation of cell walls that separate the two daughter cells

septum

structure formed in a bacterial cell as a precursor to the separation of the cell into two daughter cells

nucleosome

subunit of chromatin composed of a short length of DNA wrapped around a core of histone proteins

FtsZ

tubulin-like protein component of the prokaryotic cytoskeleton that is important in prokaryotic cytokinesis (name origin: Filamenting temperature-sensitive mutant Z)