Chapter 6: Reproduction at the cellular level

diploid

describes a cell, nucleus, or organism containing two sets of chromosomes

gamete

a haploid reproductive cell or sex cell (sperm or egg)

gene

the physical and functional unit of heredity; a sequence of DNA that codes for a specific peptide or RNA molecule

genome

the entire genetic complement (DNA) of an organism

haploid

describes a cell, nucleus, or organism containing one set of chromosomes

homologous chromosomes

chromosomes of the same length with genes in the same location; diploid organisms have these pairs and the members of each pair come from different parents

locus

the position of a gene on a chromosome

anaphase

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

cell cycle

the ordered sequence of events that a cell passes through between one cell division and the next

cell cycle checkpoints

mechanisms that monitor the preparedness of a eukaryotic cell to advance through the various cell cycle stages

cell plate

a structure formed during plant-cell cytokinesis by Golgi vesicles fusing at the metaphase plate; will ultimately lead to formation of a cell wall to separate the two daughter cells

centriole

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

cleavage furrow

a constriction formed by the actin ring during animal-cell cytokinesis that leads to cytoplasmic division

cytokinesis

the division of the cytoplasm following mitosis to form two daughter cells

G0 phase

a cell-cycle phase distinct from interphase; a cell in in this phase is not preparing to divide

G1 phase

a cell-cycle phase; phase of interphase centered on cell growth during mitosis

G2 phase

a cell-cycle phase; phase in interphase where the cell undergoes the final preparations for mitosis

interphase

the period of the cell cycle leading up to mitosis; the interim between two consecutive cell divisions

kinetochore

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

metaphase plate

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

metaphase

the stage of mitosis during which chromosomes are lined up at the metaphase plate

mitosis

the period of the cell cycle at which the duplicated chromosomes are separated into identical nuclei

mitotic phase

the period of the cell cycle when duplicated chromosomes are distributed into two nuclei and the cytoplasmic contents are divided; includes mitosis and cytokinesis

mitotic spindle

the microtubule apparatus that orchestrates the movement of chromosomes during mitosis

prometaphase

the stage of mitosis during which mitotic spindle fibers attach to kinetochores

prophase

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

quiescent

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

S phase

the second phase of interphase during which DNA replication occurs

telophase

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

oncogene

a mutated version of a proto-oncogene, which allows for uncontrolled progression of the cell cycle, or uncontrolled cell reproduction

proto-oncogene

a normal gene that controls cell division by regulating the cell cycle that becomes an oncogene if it is mutated

tumor suppressor gene

a gene that codes for regulator proteins that prevent the cell from undergoing uncontrolled division

binary fission

the process of prokaryotic cell division

FtsZ

a tubulin-like protein component of the prokaryotic cytoskeleton that is important in prokaryotic cytokinesis

origin

the region of the prokaryotic chromosome at which replication begins

septum

a wall formed between bacterial daughter cells as a precursor to cell separation