The cell cycle (MITOSIS) Flashcards
- The ability of organisms to reproduce best
distinguishes living things from nonliving matter - The continuity of life is based on the
reproduction of cells, or
Cell Division
Multicellular organisms depend on cell division
for:
– Development from a fertilized cell
– Growth
– Repair
Cell division is an integral part of the ______ __________, the life of a cell from formation to its own
division
Cell Cycle
Most cell division results in daughter cells with
identical genetic information,
DNA
- All the DNA in a cell constitutes the cell’s ________
- can consist of a single DNA
molecule (common in prokaryotic cells) or a
number of DNA molecules (common in
eukaryotic cells)
Genome
DNA molecules in a cell are packaged into
Chromosomes
Every eukaryotic species has a characteristic number of
chromosomes in each cell nucleus
(nonreproductive cells) have
two sets of chromosomes
Somatic cells
(reproductive cells: sperm and eggs)
have half as many chromosomes as somatic
cells
Gametes
Eukaryotic chromosomes consist of ____________, a complex of DNA and protein that
condenses during cell division
Chromatin
In preparation for cell division, DNA is ________ and the chromosomes __________
replicated and condense
Each duplicated chromosome has ___ ______ __________, which separate during cell
division
two sister chromatids
is the narrow “waist” of the
duplicated chromosome, where the two
chromatids are most closely attached
Centromere
Eukaryotic cell division consists of:
Mitosis
Cytokinesis
the division of the nucleus
Mitosis
the division of the cytoplasm
Cytokinesis
- Gametes are produced by a variation of cell
division called - yields nonidentical daughter cells that
have only one set of chromosomes, half as
many as the parent cell
Meiosis
In ____, the German anatomist __________ ____________ developed dyes to observe
chromosomes during mitosis and cytokinesis
1882, Walther Flemming
The cell cycle consists of
Mitotic (M) phase (mitosis and cytokinesis)
Interphase (cell growth and copying of
chromosomes in preparation for cell division)
Interphase (about 90% of the cell cycle) can be
divided into subphases:
– G1 phase (“first gap”)
– S phase (“synthesis”)
– G2 phase (“second gap”)
The cell grows during all three phases, but
chromosomes are duplicated only during the
S phase (synthesis)
Mitosis is conventionally divided into five
phases:
Prophase
Promethaphase
Metaphase
Anaphase
Telophase
Cytokinesis is well underway by
late telophase
is an apparatus of
microtubules that controls chromosome
movement during mitosis
Mitotic spindle
During _________, assembly of spindle
microtubules begins in the centrosome, the
microtubule organizing center
Prophase
(a radial array of short microtubules)
extends from each centrosome
Aster
includes the centrosomes, the
spindle microtubules, and the asters
Spindle
During ________________, some spindle
microtubules attach to the kinetochores of
chromosomes and begin to move the
chromosomes
Prometaphase
the chromosomes are all lined
up at the metaphase plate, the midway point
between the spindle’s two poles
Metaphase
IN ____________, sister chromatids separate and
move along the kinetochore microtubules
toward opposite ends of the cell
Anaphase
In _________, genetically identical daughter
nuclei form at opposite ends of the cell
Telophase
In animal cells, cytokinesis occurs by a process
known as __________, forming a cleavage
furrow
Cleavage
In plant cells, a ____ _______ forms during
cytokinesis
Cell plate
