chapter 7

gene that stimulates uncontrolled cell division

cellular protein that fluctuates in expression and is critical for regulation of cell cycle transition

the gradual loss of proliferative ability in cells

cyclin dependant protein kinase

external controls of cyclin: CDK activity that promotes cell growth

the term used for the as yet unknown cause(s) of cellular senescence

They were the first cancer cell line developed for tissue culture.

needed for increasing the population of single-celled organisms (algal blooms), multicellular tissue growth (new leaves), asexual reproduction, and replacement of cells lost to wear and tear (shedding skin, virus infection

Once daughter cells are formed, they may grow for some time (B period) before initiating DNA synthesis. Once the chromosomes are replicated and separated to opposite ends of the cell, by inward constriction of a ring of cytoskeletal proteins (C period), the membrane pinches together between them and two daughter cells are formed (D period)

prokaryotic cells have no need for a B period since they can grow quickly enough to divide their cytoplasm as soon as DNA replication is complete and chromosomes are separated.

A specific region at which replication of a bacterial chromosome commences.

the two newly created molecules of double-stranded DNA

the nuclear envelope remains intact during mitosis, and the chromosomes bind to the inner membrane of the nuclear membrane.

• An elaborate master program of molecular checks and balances ensures an orderly and timely progression through the cell cycle. • Within the overall regulation of the cell cycle, a process of DNA synthesis replicates each DNA chromosome into two nearly perfect copies (see Section 11.3). • structural and mechanical web of interwoven “cables” and “motors” of the cytoskeleton separates the replicated DNA molecules precisely into the daughter cells.

An organism or cell with two copies of each type of chromosome in its nucleus. humans have 23 different pairs of chromosomes for a diploid number of 46 chromosomes 2n=46

An organism or cell with only one copy of each type of chromosome in its nuclei.

One of two exact copies of a chromosome duplicated during replication.

The equal distribution of daughter chromosomes to each of the two cells that result from cell division.

what newly formed sister chromatids are held together along their length by

An individual genetically identical to an original cell from which it descended.

The first stage of the mitotic cell cycle, during which the cell grows and replicates its DNA before undergoing mitosis and cytokinesis.

Nuclear division that produces daughter nuclei that are exact genetic copies of the parental nucleus.

may be subject to various external influences, such as other cells or viruses and signal molecules, including hormones, growth factors, and death signals

The basic structural unit of chromatin in eukaryotes, consisting of DNA wrapped around a histone core.