Cells in their environments Flashcards
1
Q
Name the three main components of the cytoskeleton - filaments
A
2
Q
Describe actin filaments (microfilaments)
A
- Determine shape of cell
- Important for cell movement
- Muscle contraction
- Cytokinesis
3
Q
Intermediate filaments description
A
- Most diverse one - 6 su groups
- Provide mechanical strength and cell shape
- It connects cells together in tissues
4
Q
Function of microtubules
A
- Part of internal transport system for vesicles, organelles
- Essential for cell division
5
Q
What is treadmilling?
A
- Actin filaments grow at the plus end, shrink at the minus end
- Actin filaments are dynamic, extend and and contract constantly
6
Q
What is dyanmic instability
A
- Microtubules grow and shrink at the plus end, with the minus end usually anchored to the microtubule organising centre.
- Microtubules shrink about 100x faster than they grow
7
Q
Tight junctions
A
- Tight junctions prevent leakage of molecules between cells
- They link to actin
- Produce mechanical strength
8
Q
Gap junctions
A
- Directly connect to cytoplasm
- Allow transport of SMALL molecules
9
Q
What are anchoring junctions
A
They connect the cytoskeleton of one cell to another’s cytoskeleton or its extracellular matrix
10
Q
Three types of anchoring junctons
A
- Adherens (cell:cell, cell:ECM) – Actin linked
- Desmosomes (cell:cell) – Intermediate filament (IF) linked
- Hemidesmosomes (cell:ECM) – Intermediate filament (IF) linked
11
Q
Why do we need cells to connect/purpose of junctions?
A
- Joining the cytoskeleton of cells through actin or intermediate filaments provides mechanical strength to tissues
- Allows co-ordinated action:
cardiac and skeletal muscle, actin filaments are aligned allows efficient muscle contraction - In skeletal muscle cells fuse to create long multi-nucleate cells
During fusion the actin filaments are aligned
12
Q
Three major components of the ECM
A
- Collagen and elastin - strength
- Proteoglycans - stability
- Fibronectins - help cells attach to the ECM
13
Q
What are integrins
A
- Integrins are cell surface molecules that act as matrix receptors
- Connect cell to the ECM, and transmit signals into cell to sense and respond to environment (outside-in signalling)
14
Q
Define focal adhesion
A
The point at which the cell and ECM connect
15
Q
How do cancer cells effect ECM
A
- Cancer cells acquire the ability to degrade the ECM
- Push through gaps in the ECM
