Transcript Asexual Cell Reproduction

Mitosis (Cell Division)
MITOSIS
Vocab
1. Cell Cycle: the life cycle of a eukaryotic
cell, consisting of growth and division
2. Chromatin: uncoiled DNA
3. Chromosomes: coiled DNA and protein
Chromatin
4. Chromatids: identical chromosome
copies, ½ of the X shape chromosome
5. Centromere: holds the chromatids
together
Centromere
Chromatid
Chromosome
Vocab cont.
6. Homologous Chromosomes: a pair of
chromosomes with matching information
7. Cytokinesis: when the cytoplasm divides
after mitosis
Limits to Cell Growth:
1. DNA Overload:
- DNA would not be able to instruct all of
the activities going on in the cell
2. Exchanging Materials:
- As the cell size increases it would be
more difficult for a larger cell to get
oxygen and nutrients in and wastes out
Cell Division
• process by which a cell divides and
produces 2 IDENTICAL daughter cells
• Why do cells divide?
1) Growth of the organism
2) Repair damaged cells
3) Reproduction
The Steps of the Cell Cycle:
• 4 phases:
1. G1: cell growth
The Steps of the Cell Cycle:
• 4 phases:
1. G1: cell growth
2. S: DNA
replication
The Steps of the Cell Cycle:
• 4 phases:
1. G1: cell growth
2. S: DNA
replication
3. G2: cell growth
The Steps of the Cell Cycle:
• 4 phases:
1. G1: cell growth
2. S: DNA
replication
3. G2: cell growth
4. Mitosis: cell
division
(P, M, A, T)
Interphase
Cell
Membrane
Nucleolus
Nuclear
Membrane
chromatin:
(DNA)
- this is the longest
phase of the cell
cycle and includes
the G1, S, and
G2 phases
Mitosis
•
•
•
Cell Division of body cells
Shortest phase of the Cell Cycle
Consists of 4 phases
1.
2.
3.
4.
Prophase
Metaphase
Anaphase
Telophase
Mitosis Step 1: Prophase
- DNA coils up into
chromosomes, with 2
copies of each
chromosome
(sister chromatids)
held together by a
centromere
Mitosis Step 1: Prophase cont.
Spindle Fibers
- Nucleolus and Nuclear
Mem. disappear
- Spindle fibers form
Chromosomes
Mitosis Step 2: Metaphase
Spindle Fibers
Centromere
One chromatid
- Chromosomes attach
to spindle fibers
by centromeres and
line up across the
middle
2nd chromatid
Mitosis Step 3: Anaphase
Spindle Fibers
Centromere
One chromatid
- Centromeres split
apart
- Sister chromatids are
pulled to opposite
ends of the cell by the
spindle fibers
2nd chromatid
Mitosis Step 4: Telophase
• Chromatids reach
opposite ends of the
cell
• Nucleolus and
Nuclear Membrane
reappears
Mitosis Step 4: Telophase
Cleavage Furrow
(Animal cell only)
- Cell membrane
begins to separate
- Cytokinesis occurs:
division of cytoplasm
- animal cells:
cleavage furrow
- plant cells:
cell plate
The Result:
• 2 new identical daughter cells, the old cell no
longer exists
Animal Cell Mitosis
Plants
Cell Plate