Physiology chapter 2-Overview of membrane transport Flashcards
What does permeable mean?
If a substance can cross the membrane, the membrane is said to be permeable to it.
What does impermeable mean?
If a substance cannot cross the membrane, the membrane is termed impermeable to it.
Describe the plasma membrane.
Made up of phospholipids in a lipid bi-layer, hydrophobic lipids are sequestered inside, some transmembrane proteins are embedded. It is selectively permeable.
What two properties influence whether a molecule can permeate the plasma membrane?
The relative solubility of the particle in a lipid and the size of the particle.
How do certain molecules enter if not through the plasma membrane?
Protein channels and carriers.
Which two general types of forces are involved in transport across the membrane?
Passive forces and active forces.