Post on 11-Jan-2016
8.2 The Cell CycleThe sequence of growth and division of a cell
Interphase
Mitosis
IPMAT
Cell Size Limitations
Materials must be able to pass through the cytoplasm quickly
DNA material must be enough in the nucleus to control cell activities
Volume increases faster than surface area as cell’s size increase
Chromosomes Short, stringy, dark-staining
structures Contains DNA Exist as chromatin (strands of
DNA) Coils, shortens, thickens before
cell division
A. Interphase
G-1- Cell growth occurs S - Chromosomes replicate G-2- More cell growth occurs G-o phase – cells in this phase do
not reproduce, most cells of the human body are in this phase
Animal cell in prophase
Review of terms
Sister chromatids Two halves of the doubled
chromosomes
B. Mitosis Division phase Results in two new cells Chromosome sets are identical to
those of the parent cell
Phases of Mitosis
ProphaseMetaphase Anaphase
TelophaseCytokinesis
Prophase First, longest phase Sister chromatids held together by
centromere Nucleus, nucleolus disappears Centrioles move to opposite ends
of cells Spindle forms
Metaphase Short phase Double chromosomes attach to
spindle fibers at centromere Chromosomes line up at the
equator
Anaphase
Sister chromatids separate Centromeres split apart
Telophase
Reverse of prophase occurs Chromosomes uncoil Spindle breaks down Nucleolus reappears New nuclear membrane forms
around chromosomes Plasma membrane separate the
two nuclei
CytokinesisDivision of the cytoplasm
Plants – cell plate forms across cell’s equator
Animals – plasma membrane pinches along the equator
8.3 Control of Cell CycleDNA- Genetic Blueprint for Cells
Gene- segment of DNA that controls production of a single protein
Cancer- Uncontrolled cell division
Cancer Mistake in cell cycle Uncontrolled cell division Cancerous cells forms tumors
(masses of tissue) Tumors deprive normal cells with
nutrients
Factors that affect cancer Environmental
Cigarette smoke UV radiation Air and water pollution
Genetic Programmed in the genes