Final- Gliding Flashcards
Definition: Locomotion
Cell moving through space
What structure is Flagella made up of?
Tubulin (Microtubules)
What motor does Tubulin work in?
Dynein and Kinesin
Motors
What is the interior structure of flagella?
9+ 2: 9 doublets and 2 in the middle, each pair has one incomplete and one complete
INTRACELLULAR = plasma membrane surrounds it
Movement in ciliates:
How do really long flagella organize beat patterns?
Organize impulses to turn motors on and off to bend in the right direction
Molecules cross length MT so they cant slide so they bend
Movement in ciliates:
Definition: power stroke/recovery stroke
Flagella bends to have more force in one direction than the other
famous in ciliates
Movement in ciliates:
Power stroke: characteristics and direction
Flagella stays rigid, cell moves opposite direction to motion
Movement in ciliates:
Recovery mode: characteristics and direction
Cell moves back and bends
Viscosity of water is HIGH for a SMALL cell
gets pulled through water and recovers for free
Movement in Opisthokonts
Single posterior flagella
Sine wave, cell moves opposite to flagella beat
0— <—
Movement in Stramenopiles
Single posterior flagella- Mastigonemes
Mastigonemes push harder in opposite direction (surface area) and direction is backwards
0-x-x-x –>
How many times has gliding evolved?
Multiple times independantly
How does gliding work?
And requirements
Purely molecular: needs 1. a surface, 2. a cytoskelaton/motor combination and 3. something to connect the 2
No visible means of locomotion
What is Mucilage?
a sticky carbohydrate
Where is Myosin located?
On ACTIN
Diatoms
How does gliding work?
When motor turns on and moves in one direction the cell moves in the opposite direction- substrate is larger than the cell and mucilage is stuck on
What happens after the cell glides?
Myosin falls off actin and gets recycled, mucilage is stuck on and leaves a slime trail
Gliding in Diatoms
What is the problem with gliding in diatoms?
How do they get around it?
Frustrule : there is a wall between substrate and cytoskelaton
Raphe: Slit in the wall
Gliding with flagella
What 2 groups use gliding with flagella?
Euglenids & Chlamydomonas
Gliding with flagella
Flagellar gliding definition
Use flagella as a surface for gliding: needs substrate, transmembrane “something”
Tubulin and Kinesin
Motor for Tubulin
Flagelletes
Kinesin (and dynenin)
TK <3
Motor for Actin
Diatoms
Myosin
What is an IFT train
Intraflagellar transport: bundle/package things to go in each direction down the flagella
Dyenin and Kinesin go opposite ways
Gliding with Flagella
What is the transmembrane “Something” in flagellar gliding?
Membrane glycoproteins (sugars)
Gliding with Flagella
How does flageller gliding work?
When motor gets connected to glycoprotein gliding occurs, whole cell moves in opposite direction
Flagella drags cell
Gliding in Apicomplexans
Apical complex
Tip where infection takes place
Conoid: made up of MTs
Gliding in apicomplexans
How do apicomplexans become intracellular?
Cell pushes against membrane and folds it in, keeps pushing until it pinches off and creates a vesicle
Parasitophorous vesicle
Gliding in Apicomplexans
Parts of the Apical complex
5
Apical ring, Conoid (Mts), micronemes, Rhoptries, Dense Granules
A cat meows randomly during greeting
Gliding in Apicomplexans
How do Apicomplexans infect?
APICAL COMPLEX
- Micronemes: contain particles responsible for parasite to recognize and bind 2. Rhoptries and Dense granuoles : are released, contain lipids to change nature of membrane
meows randomly during greeting
recognize and bind/change membrane
Gliding in Apicomplexans
How do they avoid detection?
Rhoptries and Dense Granuoles change the composition of the lipids/proteins in the membane so host doesnt recognize
Gliding in Apicomplexans
What cytoskelaton components are involved?
Tubulin, alveoli under the membrane
Gliding in Apicomplexans
What is myosins role in gliding?
No actin?
Actin filaments are short and transient, used for gliding- polymerize and depolymerize all the time
Cell will explode (MFs shoot through) if you stop actin DEpolymerization
Gliding in Apicomplexans
What do Apicomplexans use as a substrate?
Host cell receptors
What is the difference between gliding in diatoms and apicomplexans?
What is similar?
Diatoms: actin is tough and motor moves Apicomplexans: motor is tough and actin moves
ONLY similiarity is actin/myosin
Gliding in Apicomplexans
Components of gliding
Proteins bind on to tubulin and cross alveolar membrane, bits of actin transiently polymerize, motor is stationary (bound to something rigid)
Gliding in Apicomplexans
What does TRAP do?
Binds to receptor and recognizes, also binds to aldolase and crosses membrane
Similar to mucilege in diatoms
Gliding in Apicomplexans
Direction of movement
Myosin turns on, actin moves relative to it, aldolase and trap are stationary
Cell moves in the SAME direction as motor
Gliding in Apicomplexans
How and why are TRAP/MK2 released
Located in Micronemes, released onto surface of cell at apex and helps with gliding and recognition, makes a ring of contact with TRAP
How do trypanosomes avoid detection?
Covers cell with copies of a single protein (no variety) and keep changing protein/replace with a new one - immune system cant keep up
How do trypanosomes keep replacing the membrane ?
Recombination: Mixing and moving parts of DNA, endless combinations
Variant surface glycoproteins
What makes microsporidia difficult to treat?
They have transporters that steal ATP from host directly
How do microsporida infect ?
Extracellular spores
Shoot out polar filament at high speed to penetrate host cell, inject contents into host cytoplasm
Microsporidia
What is the posterior vacuole for?
Pump water in to build up pressure, tip of spore is thin so it will fail and eject polar filament
Microsporidia infection
What is “eversion”
Polar filament turns inside out and is shot out
Microsporida infection
What is the polaroplast
Cell leaves plasma membrane behind, forms a new one with the polaroplast
Has ATP transporters here
