Centrosomes in Cytokinesis, Cell Cycle Progression and Ciliogenesis
Mitosis Chapter 8 Honors Biology Cell Division. G 2 of Interphase Chromosomes are not clear (still...
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Transcript of Mitosis Chapter 8 Honors Biology Cell Division. G 2 of Interphase Chromosomes are not clear (still...
MitosisChapter 8
Honors BiologyCell 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 textbookMitosis 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 cell-Harvard (microtubules build and break down) NARRATED VERSION
•
REAL FOOTAGE
• 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:
Interphase
Mitosis
nuclear envelope
pair of centrioles
Early Prophase Late Prophase Prometaphase
Metaphase
MitosisVCAC Mitosis Animation
(includes all of the cell cycle)Anaphase Telophase Interphase
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• Actin and myosin
form cleavage furrow
• Plants• 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.
The contractions continue and cut the cell in two.
Cleavage furrow
cell wall
former spindle equator
cell plate
vesicles converging
Plant Cytokinesis
Cell Plate
Cytokinesis Videos
• ANIMAL• Flash cytokinesis (:03
)• Cleavage of a fertilize
d frog egg (:25)
• cell division on contrast microscope (:58)
• PLANT• Mitosis and cell plate f
ormation 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• Centrioles in
centrosomes• Growth all over
the animal (usually)
• PLANT• No centrioles in
centrosomes• Growth only at meristems
What cells undergo mitosis?
• A LOT• Skin• Blood• Digestive tract
• NOT AT ALL• Nerve• muscle
Where does mitosis occur in organisms?
• PLANTSMeristems (growing tips)
• ANIMALS• 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
PLANT CELLS
Online Activity Worksheet
• Online Onion Root Tips
Practice Links
• Animal Cell Mitosis• Plant and Animal Cell
Mitosis• Nice Mitosis Animal C
ells
• Mitosis World (yes, it is as good as Disney World)