Transcript detailedmitosis - TASIS IB Biology

Happy new year!
• the jazzy version
Cell division
Prokaryotic Cells: BINARY
FISSION
• Single circular chromosome
is replicated (DNA is copied)
• Two copies of the
chromosome move to
opposite ends of the cell
• Cytoplasm splits to form
two cells
EUKARYOTIC CELLS: MITOSIS
AND CYTOKINESIS
• Long phase of interphase
• DNA is replicated
• Nucleus divides during
mitosis
• Cell divides into two
identical (clone) daughter
cells during cytokinesis
And what about average lifespan of
a cell?
• Some cell tyes divide regularly – skin cells,
epithelial cells of intestines
• Some cells (certain neuron types) do not
divide
So what is the difference between
MITOSIS and CELL DIVISION?
So what is the difference between
MITOSIS and CELL DIVISION?
• Mitosis: Division of the nucleus to form two
identical nuclei
• Cell division (cytokinesis) splitting of the
cytoplasm, so that each of the )identical)
daughter cells receives one of the nuclei and
an equal number of organelles
When do eukaryotic cells divide?
1. Growth
2. Embryonic development
3. Tissue repair
4. Eukaryotic asexual reproduction
Do our cells go on dividing forever?
What tells a cell to divide?
Are all cells the same size?
Is cell size a limiting factor?
• YES: Cell size varies according to cell type
• Surface area to volume ratio limits the
efficiency of cell metabolism and transport
mechanisms
• Smallest cell in human body is 4 μm (granular
neurons); sperm are 5 – 6 μm; red blood cells
are 30 μm (nucleus absent)
Embryonic development:
Conception
All animals begin as a fertilised egg cell (a zygote), which divides…and
divides…until it becomes an embryo
Image Credit: www.scienceclarified.com
Binary Fission…Monera
• Binary fission animation 1
Binary Fission
DNA duplicates
DNA separates & new
cell wall divides cell in
two
2 identical new cells
result
MITOSIS AND asexual reproduction
in eukaryotes
Mitosis and asexual reproduction
• Mitosis and asexual reproduction link
The Cell Cycle…
• Cell cycle at speed...
• or slowly, set to music
The cell cycle
Cytokinesis
Division of the cytoplasm
M
G0
Some cells may
stay in this stage
for over a year
G1 First growth phase.
Varies in length
G2
Second growth
phase
S
Copying of
chromosomes
G1 + S + G2 = INTERPHASE
© 2007 Paul Billiet ODWS
The cell cycles in different
cells
Cell type
Bean root tip
Cell cycle /
hours
19.3
Mouse fibroblast
22
Chinese hamster
fibroblast
Mouse small intestine
epithelium
11
Mouse oesophagus
epithelium
© 2007 Paul Billiet ODWS
17
181
Review basic vocabulary of
genetics (click and learn)
•
•
•
•
•
Genetic material
Chromatin
Chromosome
Chromatid
Centromere
Telomere
Mitosis organelles and
checkpoint controls
•
•
•
•
Centrosome
Centriole
Nucleolus
USA Genome project talking
glossary
Interphase
INTERPHASE is the
normal lifetime of a
cell, after being
“born” by division,
and before it divides
itself.
INTERPHASE is not
a stage of mitosis !
Biological Science, a Molecular Approach.
BSCS Blue Version. Heath and Company, 1996.
nucleolus (if any)
still visible
INTERPHASE:
nuclear
envelope
clearly visible
chromatin,
NO
chromosomes,
yet
http://www.fed.cuhk.edu.hk/~johnson/photomicrographs/mitosis/animal/animal_interphase.htm
INTERPHASE
Allium root tip
Coregonus blastula
OK…what tells a cell when to
divide?
• Let's get some help from the NOBEL
organisation...
• and how about some help from Harvard?
2.5.4: Describe the events that
occur in the 4 phases of mitosis
(prophase, metaphase, anaphase,
telophase)
PROPHASE
http://www.itg.uiuc.edu/technology/atlas/structures/mitosis/prophase.htm
PROPHASE
J
J
J
J
Nuclear membrane dissolves.
Nucleolus disappears.
Chromosomes form.
Centrioles migrate & form spindle.
http://www.blc.arizona.edu/courses/181gh/Lectures_WJG.01/mitosis_F.01/mitosis.html
PROPHASE
nuclear envelope
disappears
nucleolus
disappears
http://www.ac-dijon.fr/pedago/svt/documents/mitose/prophase.gif
chromosomes
become visible
PROPHASE
Allium root tip
Coregonus blastula
METAPHASE
http://iccbweb.med.harvard.edu/mitchisonlab/Pages/mt.html
METAPHASE
chromatids
spindle
centriole
http://www.chembio.uoguelph.ca/educmat/chm736/cycletx.htm
J
chromatids line up on the equator.
METAPHASE
TWO IDENTICAL COPIES OF ONE CHROMOSOME.
THIS
CHROMATID
WILL SOON
MOVE TO
NORTH POLE
THIS
CHROMATID
WILL SOON
MOVE TO
SOUTH POLE
http://genenlab.spoono.com/gnu/mandm.shtml
chromatids
spindle
centriole
Nature (408. 423, 2000).
http://www.blc.arizona.edu/courses/181gh/Lectures_WJG.01/mitosis_F.01/mitosis.html
METAPHASE
Allium root tip
Coregonus blastula
ANAPHASE
http://www.univ-orleans.fr/SCIENCES/BIOCHIMIE/MMC/accueil.htm
ANAPHASE
J
http://www.blc.arizona.edu/courses/181gh/Lectures_WJG.01/mitosis_F.01/mitosis.html
chromatids migrate
to each pole.
ANAPHASE
early
Conly Rieder http://www.wadsworth.org/BMS/SCBlinks/WEB_MIT2/HOME.HTM
late
ANAPHASE
Allium root tip
Coregonus blastula
TELOPHASE
one
daughter
nucleus
forms at
north pole
spindle
apparatus
dissolves
one
daughter
nucleus
forms at
south pole
TELOPHASE
early
late
New nuclei form at
the poles.
Cytokinesis
begins.
http://www.blc.arizona.edu/courses/181gh/Lectures_WJG.01/mitosis_F.01/mitosis.html
TELOPHASE
Allium root tip
Coregonus blastula
Practice Slide 1: Name stage
of mitosis
Practice Slide 2: Name
stage of cell cycle
Practice Slide 3: Name
stage of mitosis
Practice Slide 4: Name
stage of mitosis
Practice Slide 5: Name
stage of mitosis
Practice Slide 6: Name
stage of mitosis
Practice Slide 7: Name
stage of mitosis
Practice Slide 8: Name
stage of mitosis
Practice Slide 9: Name
stage of mitosis
Image Credit: www.bioweb.uncc.edu/
Practice Slide 10: Name
stage of mitosis
Image Credit: www.bioweb.uncc.edu/
Practice Slide 11: Name stage of
mitosis
Image Credit: www.bioweb.uncc.edu/
Practice Slide 12: Name stage of
mitosis
Image Credit: www.bioweb.uncc.edu/