Biology: Chapter 5 General Biology Flashcards

All of the following are functions of the cell membrane EXCEPT:

1. transmitting signals.
2. participating in energy transfer.
3. being freely permeable to all substances.
4. regulating the passage of materials.
5. serving as surfaces for chemical reactions.

Which of the following statements concerning phospholipids is FALSE?

1. They have two distinct regions, one strongly hydrophobic and the other strongly hydrophilic.
2. They are amphipathic molecules.
3. They have cylindrical shapes that allow them to associate with water most easily as a bilayer structure.
4. They contain a polar organic group attached to a phosphate group.
5. They contain three fatty acids chains.

In a lipid bilayer, __________ fatty acid tails face each other within the bilayer and form a region that excludes water.

1. hypertonic
2. hyperosmotic
3. hypotonic
4. hydrophilic
5. hydrophobic

If phospholipids form a spherical structure when placed in water, then which of the following is the most logical conclusion about those phosopholipid molecules?

1. They are not amphipathic.
   They contain two fatty acid chains.
2. They are cone-shaped.
3. They form a bilayer.
4. Both their ends are hydrophilic.

A key discovery that weakened the Davson-Danielle "sandwich" model of cell membranes was that:

1. membrane proteins form a solid sheet on either side of the phospholipid bilayer.
2. membrane proteins form a solid sheet separating the phospholipid layer.
3. the phospholipids do not associate with each other in the hydrophobic region of membranes.
4. membrane proteins were not uniform and did not form flattened sheets.
5. membrane proteins occurred in regular organized patterns on the surface of membranes.

Who proposed the fluid mosaic model of cell membrane structure in 1972?

1. Davson and Singer.
2. Frye and Edidin.
3. Brown and Goldstein.
4. Singer and Nicholson.
5. Davson and Danielli.

What is meant by the term “fluid mosaic model”?

1. It is the diffusion of lipid-soluble substances through the lipid bilayer.
2. It is the movement of proteins within the phospholipid bilayer.
3. It is the solubility of water in the membrane.
4. It is the method of substance transport across the membrane.
5. It is the movement of proteins from the inner surface to the outer surface of the membrane.

In the experiment in which Frye and Edidin fused the plasma membranes of a mouse and a human cell, what happened to the membrane proteins?

1. They formed a spherical structure.
2. They formed a bilayer.
3. They moved laterally across the cell surface.
4. They flip-flopped from one layer to the other.
5. They reacted with cholesterol molecules on the membrane surface.

Vegetable oil is different from animal fat in that the phospholipids in vegetable oil have fatty acid tails that:

1. forms solids at room temperature.
2. lack double bonds.
3. are saturated.
4. interact via van der Waals forces.
5. bend at each double bond.

Cholesterol within membranes functions as a(n) __________ through its interactions with both hydrophobic and hydrophilic parts of phospholipids.

1. water blocker
2. pH buffer
3. energy source
4. temperature controller
5. fluidity buffer

Which of the following statements about lipid bilayers is FALSE?

1. They are self-sealing.
2. They are inflexible.
3. They spontaneously form closed vesicles.
4. They can fuse with other bilayers.
5. They resist forming free ends.

Integral proteins:

1. are weakly bound to the surface of the membrane.
2. are strongly bound to the cytosolic surface of the membrane.
3. have no hydrophobic portions.
4. are completely embedded within the lipid bilayer.
5. are amphipathic.

A transmembrane protein differs from other membrane proteins because it:

1. is covalently linked to the outer surface of the plasma membrane.
2. is a glycoprotein with carbohydrates attached.
3. is attached to the inside of the membrane by an ionic bond.
4. completely extends through the membrane.
5. is completely embedded within the membrane.

Peripheral proteins are linked to either surface of the plasma membrane by:

1. covalent disulfide bonds.
2. associating with fatty acids through hydrophobic interactions.
3. embedding in one side of the membrane and, thus, not extending through to the other side.
4. associating with glycoproteins on the inner membrane surface.
5. bonding to integral proteins through noncovalent interactions.

Integral proteins are:

1. manufactured in nucleus.
2. manufactured by the nucleolus.
3. made by ribosomes floating free in the cytoplasm.
4. made by ribosomes located on the rough endoplasmic reticulum.
5. made by ribosomes in the vesicles.

Biological membranes are normally permeable to:

1. large, hydrophilic molecules.
2. small, hydrophilic molecules.
3. large, hydrophobic molecules.
4. small, hydrophobic molecules.
5. ABC transporters.

Which of the following molecules is least likely to cross a cellular membrane by simple diffusion?

1. carbon dioxide
2. nitrogen
3. oxygen
4. potassium ion
5. water

An ABC transporter:

1. is a type of water channel.
2. uses the energy of ATP to transport solutes.
3. uses gated channels to transport ADP.
4. is present in kidney tubules and prevents dehydration.
5. is a type of porin.

Which of the following is not a characteristic of aquaporins?

1. They are transmembrane proteins.
2. They facilitate the rapid transport of water through the plasma membrane.
3. They are located in mammalian kidney tubules.
4. They respond to specific hormones.
5. They cause dehydration.

A bottle of perfume is opened on the opposite side of the room and within minutes you begin to smell the perfume. This phenomenon is a classic example of:

1. dialysis.
2. osmosis.
3. active transport.
4. facilitated diffusion.
5. simple diffusion.

The passive movement of a substance along its concentration gradient is termed:

1. active transport.
2. dialysis.
3. diffusion.
4. exocytosis.
5. osmosis.

Simple diffusion may involve the movement of __________ through the plasma membrane down a concentration gradient.

1. small polar molecules
2. small nonpolar molecules
3. large polar molecules
4. large nonpolar molecules
5. water

Which of the following membrane activities does NOT require the expenditure of energy by the cell?

1. active transport
2. osmosis
3. endocytosis
4. exocytosis
5. synthesis of more membrane

If the concentration of solutes in a cell is less than the concentration of solutes in the surrounding fluid, then the extracellular fluid is said to be:

1. hypertonic.
2. hypotonic.
3. isotonic.
4. stable.
5. amphipathic.

The higher the concentration of solute in a solution, the __________ the effective water concentration and the __________ the osmotic pressure.

1. lower; lower
2. lower; higher
3. higher; higher
4. higher; lower
5. Answer cannot be determined from the information provided.

Consider a U-tube that initially contains pure water on one side of a selectively permeable membrane and water plus solute on the other side. Which of the following best describes what will happen next?

1. Solute molecules diffuse across the membrane faster than water molecules.
2. The fluid level rises on the side containing the pure water.
3. The diffusion of water molecules causes an osmotic pressure to build up in the tube.
4. Solute molecules are transported across the membrane by facilitated diffusion.
5. Some water molecules become "bound up" with solute molecules and do not diffuse freely.

Solutions that are isotonic:

1. are not in dynamic equilibrium.
2. have equal concentrations of solute and water.
3. have equal concentrations of solute but not water.
4. have equal concentrations of water but not solute.
5. will exhibit a net movement of water from one solution to the other.

Figure 5-1 Use the figure to answer the corresponding question(s). Refer to Figure 5-1. Which of the following statements about the red blood cells in Figure B is true?

1. These red blood cells have been placed in an isotonic solution.
2. These red blood cells have swollen in response to a hypertonic external solution.
3. These red blood cells have swollen in response to a hypotonic external solution.
4. These red blood cells have shrunken in response to a hypertonic external solution.
5. These red blood cells have shrunken in response to a hypotonic external solution.

Figure 5-1 Use the figure to answer the corresponding question(s). Refer to Figure 5-1. Which of the following statements about the red blood cells in Figure A is true?

1. There has been no net water movement.
2. There has been a net flow of water out of the cell.
3. There has been a net flow of water into the cell.
4. Pinocytosis has occurred.
5. Plasmolysis has occurred.

A patient who has had a severe hemorrhage accidentally receives a large transfusion of distilled water directly into a major blood vessel. You would expect this mistake to:

1. have no unfavorable effect as long as the water is free of bacteria.
2. have serious, perhaps fatal consequences because there would be too much fluid to pump.
3. have serious, perhaps fatal consequences because the red blood cells could shrink.
4. have serious, perhaps fatal consequences because the red blood cells could swell and burst.
5. have no serious effect because the kidney could quickly eliminate excess water.

A plant cell placed in a hypertonic solution will:

Penicillin is toxic to certain dividing bacterial cells because it prevents cell wall formation, causing the cells to burst. This indicates that the bacteria live in:

A wilted flower placed in a vase of water for several hours became stiff and stood erect. When a fresh flower was placed in a salt solution, it wilted. From this information we can say that:

Facilitated diffusion:

Carrier proteins are involved in:

Although glucose molecules constantly diffuse into a cell along their concentration gradient, equilibrium is never reached and glucose continues to enter the cell. This is a direct result of:

Studies of glucose transport in liposomes have revealed that:

Even though a bacterium contains a higher concentration of sodium ions than in the surrounding pond water, the sodium ions continue to enter the bacterium. Evidently, sodium ions are entering the cell by:

Which of the following describes how facilitated diffusion is powered?

Which of the following statements about the sodium-potassium pump is true?

In the cotransport of glucose and sodium ions:

A human white blood cell engulfs a bacterial cell by:

Pinocytosis:

Receptor-mediated endocytosis:

Figure 5-2 Use the figure to answer the corresponding question(s). The process illustrated in Figure 5-2 is called:

Figure 5-2 Use the figure to answer the corresponding question(s). The process illustrated in Figure 5-2 would most likely be used to transport:

Select the receptor mediated endocytosis events that are in the correct (before, after) order:

In cells that are constantly involved in secretion, an equivalent amount of membrane must be returned to the interior of the cell for each vesicle that fuses with the plasma membrane; if this does not occur, then what would happen?

The structures in this figure:

Plasmodesmata of plant cells are functionally equivalent to __________ of animal cells.