Question 1

Which of the following best explains why phospholipids form bilayers in aqueous environments?

Accepted Answer

Phospholipids are amphipathic, with hydrophilic heads and hydrophobic tails, causing them to arrange with heads facing water and tails facing inward.

Question 2

A scientist observes that the plasma membrane of a fish living in cold water contains a high percentage of unsaturated phospholipids. What is the most likely reason for this adaptation?

Accepted Answer

Unsaturated phospholipids increase membrane fluidity, preventing the membrane from becoming too rigid at low temperatures.

Question 3

Which of the following statements about the Fluid Mosaic Model is correct?

Accepted Answer

Phospholipids and some proteins can move laterally within the bilayer, contributing to membrane fluidity.

Question 4

A cell is placed in a hypertonic solution. What will happen to the cell?

Accepted Answer

The cell will lose water and shrink.

Question 5

Which type of membrane protein is most likely to be involved in cell-cell recognition?

Accepted Answer

Integral proteins with attached oligosaccharides (glycoproteins).

Question 6

Which of the following molecules would most easily cross a plasma membrane by simple diffusion?

Accepted Answer

Oxygen ($$O_2)$$

Question 7

A red blood cell is placed in pure water. Which of the following best describes what will happen?

Accepted Answer

Water will move into the cell, causing it to swell and possibly burst.

Question 8

Which of the following best describes the role of cholesterol in animal cell membranes?

Accepted Answer

Cholesterol acts as a fluidity buffer, restraining movement at high temperatures and preventing close packing at low temperatures.

Question 9

Which of the following amino acids would most likely be found in the transmembrane domain of an integral membrane protein?

Accepted Answer

A hydrophobic amino acid like valine

Question 10

Which process requires energy input from the cell to move substances across the plasma membrane?

Accepted Answer

Active transport

Question 11

A membrane protein is observed to span the entire membrane and is involved in transporting ions. Which type of protein is this most likely to be?

Accepted Answer

Transmembrane integral protein

Question 12

Which of the following statements about osmosis is correct?

Accepted Answer

The presence of aquaporins should speed up the process of osmosis.

Question 13

Which of the following best describes the sidedness of membranes?

Accepted Answer

Membranes have distinct inside and outside faces, with asymmetrical distribution of proteins, lipids, and carbohydrates.

Question 14

Which of the following is NOT a function of membrane proteins?

Accepted Answer

Synthesis of phospholipids

Question 15

A cell uses a sodium-potassium pump to maintain a high concentration of $$K^+$$ inside and $$Na^+$$ outside. Which equation best represents the energy requirement for this process?

Accepted Answer

$$ATP \rightarrow ADP + P_i$$

Question 16

Which of the following statements about membrane carbohydrates is true?

Accepted Answer

Membrane carbohydrates are usually short, branched chains and can be attached to proteins (glycoproteins) or lipids (glycolipids).

Question 17

Which of the following best describes facilitated diffusion?

Accepted Answer

Passive movement of molecules down their concentration gradient via transport proteins.

Question 18

A cell in a hypotonic environment will:

Accepted Answer

Gain water and swell.

Question 19

Which of the following is a real-world example of osmoregulation?

Accepted Answer

A Paramecium using a contractile vacuole to pump out excess water in a hypotonic pond.

Membrane Structure and Function (Chapter 7): Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards