Question 1

Which of the following best describes the fluid mosaic model of biological membranes?

Accepted Answer

Membranes consist of protein molecules embedded in a dynamic bilayer of phospholipids.

Question 2

What is the primary function of cholesterol in animal cell membranes?

Accepted Answer

Cholesterol makes the membrane more rigid and less fluid.

Question 3

Archaeal membrane lipids differ from bacterial and eukaryotic membrane lipids in which two major ways?

Accepted Answer

Archaeal lipids have repeating isoprene units and ether linkages.

Question 4

Which type of linkage connects the hydrophobic tails to the glycerophosphate head group in archaeal membrane lipids?

Accepted Answer

Ether linkage

Question 5

Cell membranes composed of glycerol-ether lipids biosynthesized from isoprene units are characteristic of:

Accepted Answer

Archaea

Question 6

Which of the following statements about archaeal membrane lipids is FALSE?

Accepted Answer

The glycerophosphate head and fatty acid tail of archaeal membranes are linked by an ether linkage.

Question 7

Thermophilic archaea may have tetraether lipids that:

Accepted Answer

Form monolayer membranes.

Question 8

Which of the following statements is TRUE?

Accepted Answer

Archaeal cells can form bilayers or monolayers.

Question 9

In the context of the fluid mosaic model, what is the approximate percentage of membrane-embedded proteins by mass that move laterally within the cell membrane?

Accepted Answer

$$20-80\%$$

Question 10

Which of the following is NOT a major component of biological membranes according to the fluid mosaic model?

Accepted Answer

Glucose

Question 11

Bacterial and eukaryotic phospholipids have a glycerol head and fatty acid tails. What type of bond connects the fatty acid tails to the glycerol head?

Accepted Answer

Ester bond

Question 12

Which of the following statements best explains why archaeal membranes are more resistant to heat and chemical toxins than bacterial membranes?

Accepted Answer

Archaeal membranes have ether linkages instead of ester linkages.

Question 13

Which of the following is a chemical found in eukaryotic cell membranes that regulates fluidity in extreme temperatures?

Accepted Answer

Cholesterol

Question 14

Which of the following is TRUE regarding the structure of phospholipids in both bacterial and eukaryotic membranes?

Accepted Answer

They have a glycerol head and fatty acid tails.

Question 15

Which of the following membrane types would you expect to find in an archaeal cell living in extremely hot environments?

Accepted Answer

Monolayer membrane composed of tetraether lipids.

Question 16

Which of the following statements about membrane fluidity is correct?

Accepted Answer

Cholesterol decreases membrane fluidity at high temperatures.

Question 17

Which of the following is a function of the cell envelope in bacteria?

Accepted Answer

It surrounds and protects the cell, including the cell wall and cell membrane.

Question 18

Which of the following statements about the lipid composition of archaeal membranes is correct?

Accepted Answer

Archaeal membranes contain isoprene chains with ether linkages.

Question 19

Which of the following is a major difference between bacterial/eukaryotic and archaeal membrane lipids?

Accepted Answer

Bacterial/eukaryotic membranes have ester linkages, while archaeal membranes have ether linkages.

Cell Membranes and Lipid Structure: Study Notes for General Chemistry

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