Download Mitosis Notes 8.2

Mitosis Notes 8.2
Cell Growth and
Reproduction Notes
I.
Limitations of Cell Size
A. Diffusion—nutrients move
slower and less efficient as
distances increase.
B. DNA-limit to how quickly
instructions for protein
synthesis can be copied.
C. Surface Area-cell would starve
or be poisoned from waste.
II. Reasons for Cell Division
A. to replace tissue
B. repair cells
III. Chromosomes: Coiled DNA
A. Carry genetic material.
B. Chromatin are chromosomal
strands of DNA wrapped around
protein molecules. (uncoiled DNA)
Found in a non-dividing cell)
C. Sketch and label a chromosome:
DNA
Centromere
Sister Chromatids
IV. Cell Cycle-sequence of:
A. Growth (interphase) &
B. Division (mitosis)
V. Steps of the Cell Cycle
A. Interphase – cell grows and
carries on metablolism.
1. Chromosomes (DNA) are
duplicated.
2. Cells make proteins
3. Cells repair themselves
4. Excrete wastes
5. Make ATP
6. Produce new organelles
7. Sketch and label interphase:
centrioles
B. Mitosis - period of nuclear cell
division in which two daughter
cells are formed and are identical to
the parent cell; (they have the same
number of chromosomes) increases
the number of (body) somatic cells;
helps an organism grow in size;
guarantees genetic continuity;
involves 4 phases:
st
Prophase--1
and longest phase
a. Chromatin coils up into visible
chromosomes.
b. Nucleus, nucleolus, and nuclear
membrane begin to disappear.
c. Centrioles migrate to opposite
poles of the cell. Only animal cells
contain centrioles.
d. Spindle fibers form. Function:
help separate sister chromatids.
(doubled
chromosomes)
centrioles
Spindle fibers
Metaphase--2nd phase
a. chromosomes move to equator of
the cell. Each sister chromatid is
attached to a separate spindle
fiber by its centromere.
rd
3
Anaphase:
phase
a. Centromeres split.
b. Sister chromatids are pulled apart
to opposite poles of the cell.
c. Each chromatid is a copy of one
original chromosome.
Sister
chromatid
Telophase: final phase
a. Chromosomes begin to uncoil.
b. Spindle fibers break down.
c. Nucleus, nucleolus, and nuclear
membrane reappears.
d. Cytoplasm begins to divide—
called cytokinesis
1. In animal cells, the plasma
membrane pinches in to form a
cell furrow.
2. In plant cells, a cell plate forms
along the equator.
**End result of cell cycle- 2 new
daughter cells are produced
that are identical to parent cell.
VI. Control of the Cell Cycle
A. Gene-segment of DNA that
controls production of proteins.
B. Cancer-uncontrolled cell division