Chapter 8
Cell Membrane Structure and Function Quiz
Test your understanding of the fluid mosaic model of cell membranes, the role of cholesterol, and the processes involved in transport across cellular barriers. This quiz covers key concepts from cell biology that are crucial for anyone studying the life sciences.
Topics included:
- Membrane structure
- Transport mechanisms
- Cellular behavior in different solutions
- Endocytosis and exocytosis
Singer and Nicolson's fluid mosaic model of the membrane proposed that
Membranes are a phospholipid bilayer.
Membranes are a phospholipid bilayer between two layers of hydrophilic proteins.
Membranes are a single layer of phospholipids and proteins.
Membranes consist of protein molecules embedded in a fluid bilayer of phospholipids.
Membranes consist of a mosaic of polysaccharides and proteins.
Which of the following types of molecules are the major structural components of the cell membrane?
Phospholipids and cellulose
Nucleic acids and proteins
Phospholipids and proteins
Proteins and cellulose
Glycoproteins and cholesterol
The presence of cholesterol in the plasma membranes of some animals
Enables the membrane to stay fluid more easily when cell temperature drops.
Enables the animal to remove hydrogen atoms from saturated phospholipids.
Enables the animal to add hydrogen atoms to unsaturated phospholipids.
Makes the membrane less flexible, allowing it to sustain greater pressure from within the cell.
Makes the animal more susceptible to circulatory disorders.
The primary function of polysaccharides attached to the glycoproteins and glycolipids of animal cell membranes is
To facilitate diffusion of molecules down their concentration gradients.
To actively transport molecules against their concentration gradients.
To maintain the integrity of a fluid mosaic membrane.
To maintain membrane fluidity at low temperatures.
To mediate cell-to-cell recognition.
Why are lipids and proteins free to move laterally in membranes?
The interior of the membrane is filled with liquid water.
Lipids and proteins repulse each other in the membrane.
Hydrophilic portions of the lipids are in the interior of the membrane.
There are only weak hydrophobic interactions in the interior of the membrane.
Molecules such as cellulose can pull them in various directions.
Which of the following is a characteristic feature of a carrier protein in a plasma membrane?
It is a peripheral membrane protein.
It exhibits a specificity for a particular type of molecule.
It requires the expenditure of cellular energy to function.
It works against diffusion.
It has few, if any, hydrophobic amino acids.
Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
CO2
An amino acid
Glucose
K+
Starch
Which of the following statements is correct about diffusion?
It is very rapid over long distances.
It requires an expenditure of energy by the cell.
It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
It is an active process in which molecules move from a region of lower concentration to one of higher concentration.
It requires integral proteins in the cell membrane.
Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a 0.15 M salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are
Hypotonic to both fresh water and the salt solution.
Hypertonic to both fresh water and the salt solution.
Hypertonic to fresh water but hypotonic to the salt solution.
Hypotonic to fresh water but hypertonic to the salt solution.
Isotonic with fresh water but hypotonic to the salt solution.
Mammalian blood contains the equivalent of 0.15 M NaCl. Seawater contains the equivalent of 0.45 M NaCl. What will happen if red blood cells are transferred to seawater?
Water will leave the cells, causing them to shrivel and collapse.
NaCl will be exported from the red blood cells by facilitated diffusion.
The blood cells will take up water, swell, and eventually burst.
NaCl will passively diffuse into the red blood cells.
The blood cells will expend ATP for active transport of NaCl into the cytoplasm.
Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells?
The animal cell is in a hypotonic solution, and the plant cell is in an isotonic solution.
The animal cell is in an isotonic solution, and the plant cell is in a hypertonic solution.
The animal cell is in a hypertonic solution, and the plant cell is in an isotonic solution.
The animal cell is in an isotonic solution, and the plant cell is in a hypotonic solution.
The animal cell is in a hypertonic solution, and the plant cell is in a hypotonic solution.
In most cells, there are electrochemical gradients of many ions across the plasma membrane even though there are usually only one or two electrogenic pumps present in the membrane. The gradients of the other ions are most likely accounted for by
Cotransport proteins.
Ion channels.
Carrier proteins.
Passive diffusion across the plasma membrane.
Cellular metabolic reactions that create or destroy ions.
The movement of potassium into an animal cell requires
Low cellular concentrations of sodium.
High cellular concentrations of potassium.
An energy source such as ATP.
A cotransport protein.
A potassium channel protein.
Which of the following would increase the electrochemical potential across a membrane?
A chloride channel
A sucrose-proton cotransporter
A proton pump
A potassium channel
Both a proton pump and a potassium channel
Proton pumps are used in various ways by members of every domain of organisms: Bacteria, Archaea, and Eukarya. What does this most probably mean?
Proton pumps must have evolved before any living organisms were present on Earth.
Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life.
The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism.
Cells of each domain evolved proton pumps independently when oceans became more acidic.
Proton pumps are necessary to all cell membranes.
An organism with a cell wall would most likely be unable to take in materials through
Diffusion.
Osmosis.
Active transport.
Phagocytosis.
Facilitated diffusion.
Familial hypercholesterolemia is characterized by which of the following?
Defective LDL receptors on the cell membranes
Poor attachment of the cholesterol to the extracellular matrix of cells
A poorly formed lipid bilayer that cannot incorporate cholesterol into cell membranes
Inhibition of the cholesterol active transport system in red blood cells
A general lack of glycolipids in the blood cell membranes
In receptor-mediated endocytosis, receptor molecules initially project to the outside of the cell. Where do they end up after endocytosis?
On the outside of vesicles
On the inside surface of the cell membrane
On the inside surface of the vesicle
On the outer surface of the nucleus
On the ER
A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in
Peroxisomes.
Lysosomes.
Golgi vesicles.
Vacuoles.
Secretory vesicles.
Which of the following processes includes all others?
Osmosis
Diffusion of a solute across a membrane
Facilitated diffusion
Passive transport
Transport of an ion down its electrochemical gradient
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