Q: Which equation best represents the movement of water during osmosis across a selectively permeable membrane?

$$\text{Water moves from a region of lower solute concentration to higher solute concentration}$$

Q: Which equation best represents the electrochemical gradient driving ion movement across membranes?

$$\text{Electrochemical gradient} = \text{Chemical force} + \text{Electrical force}$$

Question 1

Which of the following best describes the fluid mosaic model of the plasma membrane?

Accepted Answer

A dynamic arrangement of protein molecules bobbing in a fluid bilayer of phospholipids.

Question 2

Phospholipids are described as amphipathic molecules. What does this mean?

Accepted Answer

They contain both hydrophobic and hydrophilic regions.

Question 3

A fish species living in extremely cold water is found to have cell membranes rich in unsaturated fatty acids. What is the biological advantage of this adaptation?

Accepted Answer

Unsaturated fatty acids increase membrane fluidity, allowing proper function at low temperatures.

Question 4

Which equation best represents the movement of water during osmosis across a selectively permeable membrane?

Accepted Answer

$$	ext{Water moves from a region of lower solute concentration to higher solute concentration}$$

Question 5

A red blood cell placed in a hypotonic solution will:

Accepted Answer

Gain water, swell, and potentially lyse.

Question 6

Which of the following is a function of membrane proteins?

Accepted Answer

Facilitating cell-cell recognition.

Question 7

The sodium-potassium pump is an example of:

Accepted Answer

Active transport, using ATP to move ions against their concentration gradients.

Question 8

Which of the following molecules can most easily cross the lipid bilayer of the plasma membrane without a transport protein?

Accepted Answer

Oxygen ($$	ext{O}_2)$$

Question 9

A plant cell in an isotonic solution will:

Accepted Answer

Become flaccid and wilt.

Question 10

Which process requires energy input from ATP and moves substances against their concentration gradient?

Accepted Answer

Active transport

Question 11

What is the main electrogenic pump in plant cells?

Accepted Answer

Proton pump

Question 12

Which type of endocytosis is most specific for the uptake of certain molecules?

Accepted Answer

Receptor-mediated endocytosis

Question 13

Familial hypercholesterolemia is caused by:

Accepted Answer

Missing or defective LDL receptor proteins.

Question 14

Which equation best represents the electrochemical gradient driving ion movement across membranes?

Accepted Answer

$$	ext{Electrochemical gradient} = 	ext{Chemical force} + 	ext{Electrical force}$$

Question 15

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses transport proteins to move substances down their concentration gradient.

Question 16

During cotransport in animal cells, the uptake of glucose in the intestine is coupled to:

Accepted Answer

The diffusion of sodium ions ($$	ext{Na}^+) $$into the cell.

Question 17

Which of the following best explains why cholesterol is important in animal cell membranes?

Accepted Answer

It buffers membrane fluidity, restraining movement at high temperatures and preventing solidification at low temperatures.

Question 18

Which of the following is true about the sidedness of membranes?

Accepted Answer

The composition and distribution of proteins, lipids, and carbohydrates is asymmetrical across the membrane.

Question 19

Which process is used by secretory cells in the pancreas to release insulin into the bloodstream?

Accepted Answer

Exocytosis

Question 20

A Paramecium living in a hypotonic environment uses a contractile vacuole to:

Accepted Answer

Pump excess water out of the cell to maintain osmotic balance.

Membrane Structure and Function – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard