AP Biology Chapter 12 (The Cell Cycle- written by Campbell) Flashcards

Terms Definitions
cell division
the process in reproduction and growth by which a cell divides to form daughter cells
genome
the ordering of genes in a haploid set of chromosomes of a particular organism
binary fission
a form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size
somatic cell
any of the cells of a plant or animal except the reproductive cells
chromosomes
threadlike structures made of DNA molecules that contain the genes
chromatin
the readily stainable substance of a cell nucleus consisting of DNA and RNA and various proteins
sister chromatids
identical copies of a chromosome; full sets of these are created during the S(DNA replication) subphase of interphase
centromere
the region of the chromosome that holds the two sister chromatids together during mitosis
centriole
in animal cells, a cytoplasmic organelle that organizes the mitotic spindle fibers during cell reproductions
cell cycle
series of events that cells go through as they grow and divide
mitosis
cell division in which the nucleus divides into nuclei containing the same number of chromosomes
M phase
mitosis and cytokinesis
cytokinesis
The final stage of the cell cycle, in which the cell's cytoplasm divides, distributing the organelles into each of the two new cells.
interphase
cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases
S phase
The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.
g1 phase
the first gap phase of interphase where the cells do most of their growing, cells increase in size and make new proteins and organelles
G2 phase
Period of time during interphase--usually the shortest--during which many of the organelles and molecules required for cell division are produced (p. 245).
prophase
first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus
prometaphase
The second stage of mitosis, in which discrete chromosomes consisting of identical sister chromatids appear, the nuclear envelope fragments, and the spindle microtubules attach to the kinetochores of the chromosomes.
metaphase
the stage in mitosis in which the duplicated chromosomes line up along the equatorial plate of the spindle
anaphase
the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles
telophase
the final stage of mitosis before cytokinesis in which the separated chromosomes reach the opposite poles of the dividing cell and the nuclei of the daughter cells form around the two sets of chromosomes
mitotic spindle
An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis.
centrosome
Structure present in the cytoplasm of animal cells, important during cell division; functions as a microtubule-organizing center. A centrosome has two centrioles.
kinetochore microtubules
Connects the centrosome with the kinetochore in the centromere region of the chromosome
kinetochore
a specialized condensed region of each chromosome that appears during mitosis surrounding centromere where the chromatids are held together to form an X shape
nonkinetochore microtubules
Produces elongation of the cell as they slide past each other away from the middle of the cell (anaphase)
dynein
A large contractile protein forming the side-arms of microtubule doublets
asters
microtubules and fibers that radiate out from the centrioles
metaphase plate
An imaginary plane during metaphase in which the centromeres of all the duplicated chromosomes are located midway between the two poles
cleavage furrow
The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate.
cell plate
A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.
Density dependent inhibition
The phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another.
growth factors
regulatory proteins that ensure that the events of cell division occur in the proper sequence and at the correct rate
restriction point
The point in the G1 stage where the cell is committed to continue through the rest of the cell cycle and divide. (Some never reach this point, entering a nondividing phase G0)
kinase
Generic term for an enzyme that phosphorylates proteins.
cyclin
A cellular protein that occurs in a cyclically fluctuating concentration and that plays an important role in regulating the cell cycle.
Cdk
Cyclin-dependent kinases. A protein kinase that is active only when attached to a particular cyclin. Activity rises and falls depending on the concentration of the cyclin partner.
MPF
A cyclin-Cdk complex that causes the cell to move from interphase into mitosis
cancer
any malignant growth or tumor caused by abnormal and uncontrolled cell division
transformation
process that converts a normal cell to a cancer cell
cleavage
The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane; specifically
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