Cell Mechanics

Question 1

Functions of a cytoskeleton in eukaryotic cells

Answer 1

i) providing the structure and mechanical support for the cell
ii) providing the force for the movement of the cells
iii) transport of materials and changes in the overall shape of a cell

Question 2

Describe Cell Adhesion Mechanisms

Answer 2

i) cell adhesion mechanisms are mainly categorised as specific interactions and non-specific interactions
ii) double-layer repulsion normally deters a cellular entity in contact with a substrate
iii) when ligand/receptor interaction is involved in a cell-substrate contact, the contact area normally increases as the ligand density on the substrate increases

Question 3

Cell Migration

Answer 3

In general, the focal adhesions of a moving cell appear to exert stronger traction
forces

Question 4

Plasma membrane

Answer 4

i) The basic structure of the membrane is a lipid bilayer, with two sheets of
phospholipids arranged tail to tail
ii) The lipid bilayer serves as a hydrophobic barrier, confining hydrophilic molecules
to the inside or the outside of a cell (or organelle)
iii) Some membrane proteins help transport specific molecules across the membrane

Question 5

What is considered an isotonic material

Answer 5

greater than 300 mosmol

Question 6

What is an OUTSTANDING feature of red blood cells? And one downside?

Answer 6

Capable of large deformation (as much as 74% increase in volume) with little change in the surface area (7%). However, it is not good at resisting shear force.

Question 7

When asked for elastic micro-pillar technique use:

Answer 7

F = (3EI/L^3)*d

Question 8

Is the cell membrane (phospholipid bilayer) strong or weak in resisting bending and stretching forces? (separately)

Answer 8

Weak resistance to bending. Strong resistance to stretching.

Question 9

How does a white-blood cell normally behave?

Answer 9

As a liquid-droplet with a cortical tension on its surface

Question 10

Into what two categories can cell adhesion mechanisms be characterised?

Answer 10

Specific-interaction and non-specific interaction

Question 11

Cytoskeleton is important for…

Answer 11

cell shape and strength

Question 12

What supplies the dynamic contractile force in cell movement?

Answer 12

Microfilaments (actin filaments)

Question 13

In deformation, what kind of elasticity does a red blood cell have?

Answer 13

Viscoelasticity

Question 14

What effect does movement of a fibroblast cell have on focal adhesions?

Answer 14

Exerts stronger traction forces