Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
19 Cards in this Set
- Front
- Back
Microtubule Organizing Centers (MTOC)
|
Centrosome, spindle poles, basal body. Minus end stabilized in the MTOC's
|
|
Gamma-TURC
|
Initiates the process of singlet microtubule formation from the minus end in regards to centriole formation. Has a gamma tubulin unit
|
|
Centriole
|
Triplet microtubules, form mother and daughter centrioles that are perpendicular to each other.
|
|
Kinesin Motors
|
Anterograde movement, towards plus end of microtubule. Stepping cycle between two heads on two swiveling stalks; forward head bind beta tubulin, releases ADP and gets ATP. This causes a conformational change in the neck linker and the rear head swings forward. ATP is hydrolyzed from rear head and process repeats. Direct
|
|
Dynein Motors
|
Retrograde movement, towards minus end. Stem region binds dynactin, and this is what interacts with cargo
so it is different than kinesin in that it is an indirect interaction. ATPase function on a head region that turns and pulls itself along.
|
|
Cilia and Flagella Movement
|
9 doublet microtubules arranged in circular fashion, with a central pair of singlet microtubules.
Each doublet has an A and a B tubule. Outer and inner arm dyneins are attached to the A tubule of one doublet and interact with the B tubule of the next doublet. Nexin protein actually connects one doublet to the next. As dyneins pull along one side, the structure gets kinked over, and so on for the other side. This is what creates the whip-like back and forth movement. Problems can cause infertility because
of the sperm and fallopian tubes, hearing, respiration, others.
|
|
Nexin
|
Connects one of nine doublet microtubules in a cilia or flagella to the next
|
|
Stages of Mitosis
|
Interphase
Prophase Prometaphase Metaphase Anaphase Telophase Cytokinesis |
|
Interphase
|
Chromosome duplication
|
|
Prophase
|
Breakdown of interphase microtubule display, replacement by mitotic asters. Condensation of chromosomes
|
|
Prometaphase
|
Nuclear envelope breaks down, chromosomes captured, bi-oriented. NOTE: Some chroms must be pulled one way, others the other way to get them lined up at metaphasic plane. At one side of kinetochore, Kinesin-13 and dynein may be acting to destabilize and shrink, while the other side Kinesins are walking toward positive tip, growing it
|
|
Metaphase
|
Chromosomes aligned at the metaphasic plate
|
|
Anaphase
|
APC/C activated, cohesins degraded.
A. Chrom movement to poles B. Spindle pole separation |
|
Telophase
|
Nuclear envelope starts to reassemble, assembly of contractile ring
|
|
Cytokinesis
|
Reformation of interphase microtubule display, contractile ring forms cleavage furrow
|
|
Zone of Interdigitation
|
Region where polar microtubules are overlapping and interacting
|
|
3 types mitotic microtubules
|
1.Polar - from spindle pole to eachother and to telomeres of chroms
2.Kinetochore - from spindle pole to kinetochores of chroms 3.Astral - from spindle pole to the outer plasma membrane, anchoring |
|
Pulling forces on spindle pole
|
Astral - dyneins walk toward spindle pole from plasma membrane
Polar - Kinesin bind one tubule, walk on other toward positive end |
|
Kinetochore Microtubule Instability & End Capture
|
There are kinesins actually on the kinetochore, and if they come into contact with the end of a kinetochore microtubule, the kinesin will move towards positive end of tubule and this captures it. If a kinetochore tubule doesn't get captured it will disassemble and then reassemble until it is captured at the kinetochore.
|