Cell motility Flashcards
(34 cards)
What does cell motility require?
- energy
- guidance
- mechanical interaction with something out the cell
- swimming vs crawling
- microtubules vs actin microfilaments
Describe what is required for cells to swim?
microtubules
Describe what is required for cells to swim?
actin microfilaments
What are microtubules composed off?
hollow tubes of a & b tubulin (they alternate)
- 13 protofilaments
- has intrinsic polarity due to the 2 tubulin subunits
What is the structure of microtubule-based motility?
Cilia & Flagella
Where is flagella used in cells?
sperm/ protozoa
Where is cilia used in cells?
respiratory tract/reproductive tract
What is the difference between cilia & flagella?
they have the same structure, but they have different lengths:
cilia - 2-10 x 0.25um
flagella - 100-200 x 0.25um
What is larger - cilia or flagella?
flagella (10 times larger)
What is the major functional structure of the cilia & flagella?
Axoneme
What is the microtubular arrangement of the axoneme?
9+2 microtubule assembly
Describe the 9+2 microtubule assembly composition
- 9 outer doublets
- Radial spokes
- Inner pair
How many protofilaments do complete (A) fibres have?
13 protofilaments
How many protofilaments do incomplete (B) fibres have?
10
What is dynein arms?
the motor protein in microtubules
What links the 2 central doublets?
Dynein - the presence of ATP allows sliding of microtubules (in separate directions)
What are the 2 dynein arm-dependent functions?
Inner arm - waveform
Outer arm - power
What is the transition zone?
where flagella/cilia meets the plasma membrane
What is the function of basal bodies?
cell motility
What happen if actin acts on a muscle?
moves organism
What happen if actin acts on a non-muscle?
moves cells/tissues
Does an actin monomer have polarity?
Yes
What is in the middle of an actin subunit?
bound nucleotide (ATP)
What can occur to the ATP molecule in the middle of a G actin filament?
It can be hydrolysed released energy and leaving ADP
