Physiology chapter 2-Overview of membrane transport

Question 1

What does permeable mean?

Answer 1

If a substance can cross the membrane, the membrane is said to be permeable to it.

Question 2

What does impermeable mean?

Answer 2

If a substance cannot cross the membrane, the membrane is termed impermeable to it.

Question 3

Describe the plasma membrane.

Answer 3

Made up of phospholipids in a lipid bi-layer, hydrophobic lipids are sequestered inside, some transmembrane proteins are embedded. It is selectively permeable.

Question 4

What two properties influence whether a molecule can permeate the plasma membrane?

Answer 4

The relative solubility of the particle in a lipid and the size of the particle.

Question 5

How do certain molecules enter if not through the plasma membrane?

Answer 5

Protein channels and carriers.

Question 6

Which two general types of forces are involved in transport across the membrane?

Answer 6

Passive forces and active forces.