Biology 320 exam 3 Boisestate 2026
Questions and Answers
Why do phospholipids form bilayers in water? - Correct answer-The hydrophilic
heads form hydrogen bonds with water molecules, while the hydrophobic tails
avoid water.
Which of the following is NOT a function of human plasma membrane proteins?
choices:
1. Allow specific ions to cross the plasma membrane
2. Serve as receptors to convey extracellular signals to the cell interior
3. Catalyze the production of small molecules used for cell signaling
4. Generate energy required for lipids to diffuse through the membrane - Correct
answer-4. Generate energy required for lipids to diffuse through the membrane
The fluidity of the plasma membrane depends upon which phospholipids it
contains. You've learned that phospholipids with unsaturated hydrocarbon tails
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,contain ____________. Lipid bilayers with a large proportion of unsaturated tails
are ________.
Correct! - Correct answer-Double bonds between adjacent carbon atoms; MORE
fluid
In eukaryotic cells, new phospholipids are made by enzymes found
_________________. - Correct answer-on the cytosolic side of the ER membrane
How does cholesterol affect the lipid bilayer of animal cells? - Correct answer-
Cholesterol makes the lipid bilayer less fluid
A bacterium leaves a human host and is deposited into the cold external world.
Which of the following would allow the bacterium to maintain a constant level of
membrane fluidity when introduced into the cold environment? - Correct answer-
Produce phospholipids that have shorter fatty acid tails
When a vesicle fuses with the plasma membrane, the monolayer that was facing
the inside of the vesicle will face the outside of a cell. (T/F) - Correct answer-True
Lipid bilayers are found in all of the following structures EXCEPT for: - Correct
answer-Chromosomes
Which of the following steps take place in the synthesis of a new phospholipid?
1. Enzymes suspended in the ER lumen first synthesize the lipids
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, 2. Enzymes catalyze the movement of phospholipids between the two monolayers
of the ER membrane
3. Lipid bilayers are moved as vesicles from the ER to the golgi
4. Within the Golgi, sugars are added to some phospholipids
5. Glycolipids feature sugars on their hydrophilic heads and within their
hydrophobic tails - Correct answer-2,3,4
Which of the following statements describe the phospholipids found in the plasma
membrane? Select all that are true.
1. Each phospholipid contains three fatty acid tails
2. Portions of these molecule are hydrophilic, while other portions contain
nonpolar covalent bonds
3. Their fatty acid tails interact with each other through a large network of
hydrogen bonds
4. The hydrocarbon tails of the phosopholipids form alpha helical structures
5. Different phospholipids can very in the length of their hydrocarbon tails -
Correct answer-2 and 5
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Questions and Answers
Why do phospholipids form bilayers in water? - Correct answer-The hydrophilic
heads form hydrogen bonds with water molecules, while the hydrophobic tails
avoid water.
Which of the following is NOT a function of human plasma membrane proteins?
choices:
1. Allow specific ions to cross the plasma membrane
2. Serve as receptors to convey extracellular signals to the cell interior
3. Catalyze the production of small molecules used for cell signaling
4. Generate energy required for lipids to diffuse through the membrane - Correct
answer-4. Generate energy required for lipids to diffuse through the membrane
The fluidity of the plasma membrane depends upon which phospholipids it
contains. You've learned that phospholipids with unsaturated hydrocarbon tails
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,contain ____________. Lipid bilayers with a large proportion of unsaturated tails
are ________.
Correct! - Correct answer-Double bonds between adjacent carbon atoms; MORE
fluid
In eukaryotic cells, new phospholipids are made by enzymes found
_________________. - Correct answer-on the cytosolic side of the ER membrane
How does cholesterol affect the lipid bilayer of animal cells? - Correct answer-
Cholesterol makes the lipid bilayer less fluid
A bacterium leaves a human host and is deposited into the cold external world.
Which of the following would allow the bacterium to maintain a constant level of
membrane fluidity when introduced into the cold environment? - Correct answer-
Produce phospholipids that have shorter fatty acid tails
When a vesicle fuses with the plasma membrane, the monolayer that was facing
the inside of the vesicle will face the outside of a cell. (T/F) - Correct answer-True
Lipid bilayers are found in all of the following structures EXCEPT for: - Correct
answer-Chromosomes
Which of the following steps take place in the synthesis of a new phospholipid?
1. Enzymes suspended in the ER lumen first synthesize the lipids
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, 2. Enzymes catalyze the movement of phospholipids between the two monolayers
of the ER membrane
3. Lipid bilayers are moved as vesicles from the ER to the golgi
4. Within the Golgi, sugars are added to some phospholipids
5. Glycolipids feature sugars on their hydrophilic heads and within their
hydrophobic tails - Correct answer-2,3,4
Which of the following statements describe the phospholipids found in the plasma
membrane? Select all that are true.
1. Each phospholipid contains three fatty acid tails
2. Portions of these molecule are hydrophilic, while other portions contain
nonpolar covalent bonds
3. Their fatty acid tails interact with each other through a large network of
hydrogen bonds
4. The hydrocarbon tails of the phosopholipids form alpha helical structures
5. Different phospholipids can very in the length of their hydrocarbon tails -
Correct answer-2 and 5
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