B2.1 Membranes and membrane transport HL

Question 1

Effect of saturated vs. unsaturated fatty acids on membrane fluidity?

Answer 1

Saturated fatty acids decrease fluidity; unsaturated increase it due to kinked structures

Question 2

Temperature’s impact on membrane fluidity?

Answer 2

Higher temperatures increase fluidity; lower temperatures decrease it.

Question 3

Cholesterol’s role in regulating membrane fluidity?

Answer 3

Increases fluidity at low temperatures; decreases at high temperatures.

Question 4

Membrane fluidity’s importance in endocytosis and exocytosis?

Answer 4

Essential for vesicle formation and fusion in material transport.

Question 5

Cold-blooded animals’ adaptation for membrane fluidity in cold?

Answer 5

Increase unsaturated fatty acids to maintain fluidity.

Question 6

What are gated channels?

Answer 6

Transport proteins that open/close in response to stimuli.

Question 7

Define direct active transport.

Answer 7

Uses energy to move substances against their gradient

Question 8

Explain indirect active transport

Answer 8

Couples movement of substances using gradients

Question 9

Sodium-potassium pump’s role in neurons?

Answer 9

Maintains electrochemical gradient for nerve impulses.

Question 10

Ligand-gated ion channels in neurons?

Answer 10

Open for neurotransmitters, triggering nerve impulses.

Question 11

What are cell-adhesion molecules (CAMs)?

Answer 11

Proteins for cell binding, essential for tissue formation.

Question 12

Role of tight junctions?

Answer 12

Create seals between cells, preventing molecule passage.

Question 13

Function of gap junctions?

Answer 13

Form channels for small molecule/ion transfer.

Question 14

Adhesive junctions’ contribution to cell structure?

Answer 14

Provide mechanical stability by anchoring cells.

Question 15

CAMs’ importance in immune responses?

Answer 15

Facilitate immune cell interactions and pathogen recognition.