Transcript Honors Biology Mitosis Power Point

Mitosis
Chapter 8
Honors Biology
Cell Division
G2 of Interphase
• Chromosomes are
not clear (still
chromatin)
• Nucleolus visible
• Nuclear envelope
• Centrosomes
duplicated (each
centrosome has 2
centrioles)
Why is mitosis important?
• 1. Growth
• 2. Cell replacement
• 3. Asexual Reproduction
pp. 130-131 of textbook
Mitosis Stages
G2 Prophase
Prometaphase
Name the structures and
describe what is happening.
Prophase
• Chromatin fibers coil
to become dense
chromosomes
• They join at the
centromere as sister
chromatids
2 centrosomes
made in G2
Prophase
• Nucleolus Disappears
• Spindle Fibers Form as microtubules out
from the centrosomes (MTOC)
• Asters form (shorter microtubules extending
from centrosomes)
See the chromosomes
condense
• Centrosomes
move away from
each other,
propelled by the
lengthening
microtubules
between them
• Mitosis Animation
(show through
prophase)
Prometaphase
• Nuclear envelope
disintegrates (vesicles)
• Each sister chromatid has
a kinetochore at
centromere
• Kinetochore spindles
attach to kinetochore
• Non-kinetochore
spindles pole to pole
Prometaphase
• How many chromosomes
are there?
How many sister
chromatid pairs are
there?
• ANSWER: 4, 4
Kinetochore :
attach spindle fibers to chromatid
• Kinetochore in pink
Kinetochore
*Microtubule dynamics animation (+/- ends,
jerking)
• Spindle microtubules at centromere
• During prometaphase some spindle
microtubules attach to the kinetochores
• Chromosomes “tug of war” to poles begins
McGraw-Hill Mitosis
and Cytokinesis
• Microtubules lengthen and shorten by the
addition or removal of tubulin.
• Kinetochore microtubules shorten in the
region of the kinetochore, pulling the
chromosomes apart.
• Polar microtubules elongate to push
against each other and thus, push the two
centrosomes apart.
COOL SITE
• ** GO TO Biovision: Inner life of a cellHarvard (microtubules build and break
down) NARRATED VERSION
•
REAL FOOTAGE
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Animations Scroll down to Chapter 10
Microtubule dynamics in prophase
Capture of a kinetochore
Alignment of chromosomes
Aligned chromosomes oscillate
continuously – “jerking”
• AND MUCH MORE
Metaphase Anaphase Telophase
Name the structures and describe
what is happening.
Metaphase
Centrioles now at
opposite poles
Sister chromatids line
up at the metaphase
plate (equator)
Each chromosome has
its own kinetochore
coming from opposite
poles
Anaphase
• Spindle fibers pull
the chromatids to
the opposite
poles
• Centromere split
• Nonkinetochore
microtubules
lengthen
Telophase
• Chromatids are
now at the
opposite ends
of the cell
• Late:
Chromatids
back to
chromatin
• Spindles
dissolve
Reforming of
nucleolus and
nuclear envelope
Telophase: end with two equal
daughter cells
NAME THE PHASES:
Mitosis
Interphase
Early Prophase
pair of centrioles
nuclear
envelope
Late Prophase
Prometaphase
Mitosis
VCAC Mitosis Animation
(includes all of the cell cycle)
Anaphase
Telophase
Interphase
Metaphase
Cell splits
SHOWTIME
• Mitosis Movie
• Mitosis (narrated movie)
• Interactive human mitosis animation
Cytokinesis (actually at the end
of telophase)
Separation
of the
cytoplasm
Cytokinesis
• Animals
• Plants
• Actin and myosin
form cleavage furrow
• Vesicles from the
Golgi make cell plate
Animal Cytokinesis
Mitosis is over, and
the spindle is now
disassembling.
Band of microfilaments at the
former spindle equator contracts.
Cleavage furrow
The contractions
continue and cut
the cell in two.
Plant Cytokinesis
cell wall
former
spindle
equator
Cell
cell
plate
Plate
vesicles
converging
Cytokinesis Videos
• ANIMAL
• Flash cytokinesis
(:03)
• Cleavage of a
fertilized frog egg
(:25)
• cell division on
contrast microscope
(:58)
• PLANT
• Mitosis and cell plate
formation of giant
chromosomes
Haemanthus (1:14)
• Endosperm cell
division (:07)
• Cytokinesis Animal
and Plant Cells (3:48)
• Mitosis and Meiosis Choose mitosis rap)
Mitosis differences
• ANIMAL
• PLANT
• Centrioles in • No centrioles in
centrosomes
centrosomes
• Growth all over • Growth only at meristems
the animal
(usually)
What cells undergo mitosis?
• A LOT
• Skin
• Blood
• Digestive tract
• NOT AT ALL
• Nerve
• muscle
Where does mitosis occur in
organisms?
• PLANTS
• ANIMALS
Meristems (growing tips)
• Most places: skin,
hair, blood, digestive
tract
• DNA tube mitosis real
mitosis
NICE REVIEW OF MITOSIS
• Biology Animation:
Cell Cycle + Quiz
• Can click on each
phase
• Can take quiz (can
review if incorrect
answer)
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A: Interphase
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A: anaphase
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A:metaphase
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A:prophase
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A. telophase
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A. prophase
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A. telophase
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A. anaphase
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A. metaphase
Which phase of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
A. interphase
P
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Online Activity Worksheet
• Online Onion Root
Tips
Practice Links
• Animal Cell Mitosis
• Plant and Animal Cell
Mitosis
• Nice Mitosis Animal
Cells
• Mitosis World (yes, it
is as good as Disney
World)