Download Cell Cycle

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

page
1
page
2
page
3
page
4
page
5
page
6
page
7
page
8
page
9
page
10
page
11
page
12
page
13
page
14
page
15
page
16
page
17
page
18
page
19
page
20
page
21
page
22
page
23
page
24
page
25
page
26
page
27
page
28
page
29
page
30
page
31
page
32
page
33
page
34
Document related concepts
no text concepts found
Transcript 
Cell Cycle
• The dividing and non-dividing stages in the life of
a cell.
• Phases:
1. Interphase:
Interphase growth and DNA replication
2. Prophase
3. Metaphase
Mitotic
division
4. Anaphase
5. Telophase
Cell Cycle
S
phase
G1
interphase
Mitosis
-prophase
-metaphase
-anaphase
-telophase
G2
Interphase
• Comprises about 90% of the cell cycle.
cycle
• Cellular growth:
growth
a. protein synthesis
b. metabolic activities
c. DNA synthesis
• Made up of three phases:
phases
1.
2.
3.
G1 phase
S phase
G2 phase
Interphase
1. G1 (gap) phase:
a. protein synthesis and metabolic activities.
b. most cell are arrested in this phase.
phase
2. S phase:
a. DNA replication takes place.
3. G2 (gap) phase:
a. Cellular growth and preparation for M phase.
phase
•Mitosis:
•Eukaryotic cells (somatic cells) (asexual reproduction)
•DNA duplicates -> 2 sister chromatids
•Chromosomes attach to spindle and separate
•Used for growth, repair and reproduction (in singlecell organisms)
•Makes 2 identical cells
Binary Fission
• Bacteria, cyanobacteria, and most single celled
organisms reproduce by binary fission.
fission
bacteria
chromosome
plasma membrane
Asexual
Reproduction
Prophase
• Longest phase
• Nucleolus disappears
• Chromatin material condenses into chromosomes,
chromosomes
consisting of two sister chromatids.
chromatids
• Centrioles move apart (not found in plants).
• Spindle fibers form and attach from centrioles to
centromeres.
• Nuclear envelope fragments and disappears
Prophase
early prophase
late prophase
centrioles
spindle fibers
aster
fibers
nuclear envelope
disappearing
centromere
aster
fibers
centromere
centriole
spindle fiber
sister
chromatid
kinetochores
sister
chromatid
Metaphase
• Shortest phase
• Centrioles are at opposite ends of the cell and
attached with aster fibers.
fibers
• Chromosomes move to the metaphase plate
(equatorial plate - center of cell).
Metaphase
centrioles
aster
fibers
spindle fibers
metaphase plate
Metaphase spindle of a culture cell
Anaphase
• Centromeres uncouple and spindle fibers shorten.
• Sister chromatids separate and move apart.
• After separation, chromatids are now considered
chromosomes.
chromosomes
• During this phase, the cell contains twice the normal
number of chromosomes.
chromosomes
• Cell begins to elongate.
elongate
• At the end, there are equal numbers of chromosomes
at the poles.
Anaphase
No longer sister chromatids,
chromatids now chromosomes
aster
fibers
spindle fibers
centrioles
Telophase
• Cleavage furrow develops in animal cells (Cytokinesis
begins).
• Cell plate develops in plants (no cleavage furrows in
plants).
• Nucleolus reappears.
• Nuclear membrane reappears.
• Chromosomes uncoil.
• In the end, two genetically identical nuclei (karyokinesis
completed) are present.
cell plate
Hela cell
Intracellular Organization of Microtubules
Figure 11.43 Structure of
Centrosomes (Part 1)
Figure 11.43 Structure of
Centrosomes (Part 2)
Structure of a Centriole
Formation of the Mitotic Spindle (Part 1)
Formation of the Mitotic Spindle
Related documents