B2.1 Membranes and membrane transport SL

Question 1

Composition of biological membranes?

Answer 1

Lipids, proteins, carbohydrates.

Question 2

Structure of a phospholipid?

Answer 2

Glycerol, hydrophilic phosphate head, hydrophobic fatty acid tails.

Question 3

Amphipathic nature of phospholipids?

Answer 3

Hydrophobic tails, hydrophilic heads.

Question 4

Phospholipid arrangement in water?

Answer 4

Bilayer: hydrophobic tails inward, hydrophilic heads outward

Question 5

Role of cholesterol in lipid bilayers?

Answer 5

Modulates fluidity and stability.

Question 6

What determines lipid bilayer’s selective permeability?

Answer 6

Hydrophobic core blocks ions/polar molecules, allows non-polar molecules.

Question 7

Simple diffusion?

Answer 7

Passive movement down concentration gradient.

Question 8

Integral vs. peripheral proteins?

Answer 8

Integral: embedded in bilayer; Peripheral: on surface.

Question 9

Function of aquaporins?

Answer 9

Rapid water transport across membranes.

Question 10

Facilitated diffusion?

Answer 10

Passive transport via protein channels/carriers.

Question 11

Channel vs. carrier proteins?

Answer 11

Channel: pores; Carrier: bind and transport molecules.

Question 12

Active transport?

Answer 12

Movement against concentration gradient, requires energy.

Question 13

Glycoproteins and glycolipids function?

Answer 13

Cell recognition, signaling, adhesion.

Question 14

Fluid mosaic model?

Answer 14

Dynamic mix of moving phospholipids and proteins.

Question 15

Role of the glycocalyx?

Answer 15

Cell protection, adhesion, recognition.