Biochemistry- How do nerves work

Question 1

What is a biological membrane?

(revision)

Answer 1

• Barrier- defining the inside and out
• Selective permeability
• Dynamic structures containing lipids and proteins
• Internal as well as external membranes

Question 2

What is selective permeability?

What are the 3 ways this can be achieved?

Answer 2

allows cell to control what molceules can come in and out of the cell.

3 ways this can be achieved:

Passive transport

Active transport

Transport using vesicles.

Question 3

What is a plasma membrane?

Answer 3

Plasma Membrane-dynamic structure in which proteins float in a sea of lipids.

Proteins allow molecules to come into cell through passive fusion.

Question 4

What is a lipid made of and what are its functions?

Answer 4

Polar head and Non-polar tail

Function:

Energy storage

components of cell membrane

Question 5

How are the hydrocarbon tails in lipid bilayers held together?

Answer 5

van der Waals forces

Question 6

How is a nerve transmitted?

(6 steps)

Answer 6

1. Polarization of the neuron’s membrane
2. Resting potential gives the neuron a break.
3. Action potential: Sodium ions move inside the membrane.
4. Repolarization: Potassium ions move outside, and sodium ions stay inside the membrane
5. Hyperpolarization: More potassium ions are on the outside than there are sodium ions on the inside.
6. Refractory period puts everything back to normal: Potassium returns inside, sodium returns outside.