Question 1

Which of the following best describes the amphipathic nature of phospholipids in biological membranes?

Accepted Answer

They have both a hydrophilic head and a hydrophobic tail.

Question 2

Which of the following statements about the plasma membrane is correct?

Accepted Answer

It separates the cell’s interior from the external environment.

Question 3

What is the primary function of fats (triglycerides) in cells?

Accepted Answer

Energy storage

Question 4

Which of the following is a key structural difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have only single bonds between carbons, while unsaturated fatty acids have one or more double bonds.

Question 5

Which of the following best explains why highly unsaturated lipids are liquid at room temperature?

Accepted Answer

The kinks from double bonds prevent tight packing of the hydrocarbon chains.

Question 6

Which of the following is NOT a component of a phospholipid?

Accepted Answer

Three fatty acids

Question 7

What is the effect of cholesterol on membrane permeability?

Accepted Answer

It reduces membrane permeability.

Question 8

Which of the following molecules would most easily cross a pure phospholipid bilayer?

Accepted Answer

O$$_2$$

Question 9

Why do phospholipids spontaneously form bilayers in water?

Accepted Answer

Their hydrophilic heads interact with water, while their hydrophobic tails avoid water.

Question 10

Which of the following is true about the asymmetry of the lipid bilayer in cell membranes?

Accepted Answer

Glycolipids are found only on the extracellular side.

Question 11

A scientist increases the temperature of a cell membrane. What is the most likely effect on the membrane?

Accepted Answer

The fluidity of the membrane increases.

Question 12

Which of the following best describes the movement of phospholipids within a membrane?

Accepted Answer

They move laterally within the same layer but rarely flip to the other side.

Question 13

Which of the following is a function of the plasma membrane?

Accepted Answer

Facilitating chemical reactions necessary for life

Question 14

Which of the following statements about glycolipids is correct?

Accepted Answer

They have a hydrophilic sugar head group and two fatty acid tails.

Question 15

Which of the following best explains why butter is solid at room temperature while vegetable oil is liquid?

Accepted Answer

Butter contains highly saturated fatty acids, while vegetable oil contains highly unsaturated fatty acids.

Question 16

Which of the following is a characteristic feature of steroids?

Accepted Answer

A bulky, four-ring structure

Question 17

A mutation causes a cell to produce phospholipids with much longer and more saturated fatty acid tails. What is the most likely effect on the cell membrane?

Accepted Answer

The membrane will have lower permeability and fluidity.

Question 18

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

Accepted Answer

It is amphipathic and helps regulate membrane fluidity and permeability.

Question 19

Which of the following is true regarding the selective permeability of the lipid bilayer?

Accepted Answer

Small, nonpolar molecules cross easily, while ions and large polar molecules do not.

Question 20

Which of the following is a real-world example of the importance of membrane compartmentalization in eukaryotic cells?

Accepted Answer

Lysosomes containing digestive enzymes are separated from the cytoplasm to prevent cellular damage.

Lipids, Membranes, and the First Cells: Structure and Function of Biological Membranes

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