Transcript Cell Cycle

Cell Cycle
All cells go through the
cell cycle, some faster
than others.
Limits to Cell Size
 Diffusion
– Limit to the rate at which O2 & CO2 can
diffuse into and out of cell
 DNA
– Code for Proteins
– Can only translate into proteins SO fast
 Surface
Area to Volume Ratio
– The volume of a cell increases faster
than the surface area (see diffusion)
Interphase
A cell spends MOST of its life here.
 During interphase it:

–
–
–
–
Grows back to full size
Does its JOB!!!
Copies DNA
Gets ready to divide (if it is going to)
Interphase
 Remember:
– Most of the time DNA is “unwound” as
chromatin so it can be “read”. Prior to
cell division it condenses into visible
chromosomes.
Mitosis
A process in which
the cell’s
chromosomes
separate into
two(2) new nuclei.
 (the chromosomes
duplicate before
dividing)

Prophase
Chromosomes
condense (appear)
 Nuclear membrane
dissolves
 Centrioles move to
poles
 Spindles begin to
form

Metaphase
Chromosomes line
up at “equator”
 Spindles attach to
centromere of each
chromosome
 Spindles attach to
centrioles (in
animal cells)
 Ready to Divide!

Anaphase
Centromere splits
 Chromosome
divides into sister
chromatids
 Chromatids begin
to move towards
“poles” as spindles
shorten

Telophase




Chromosomes arrive
at ends of cell
Chromosomes
unwind
Nuclear membrane
reforms
Nucleolus reappears
Cytokinesis




Cell Membrane pinches
inward
Organelles distribute
between two new cells
In plant cells a new cell
wall grows between the
cells
EACH NEW CELL HAS A
COMPLETE SET OF DNA