Biology 5.1-5.9

A cell that neither gains nor loses water when it is immersed in a solution is A) isotonic to its environment. B) hypertonic to its environment. C) hypotonic to its environment. D) metabolically inactive. E) dead.

A

A plant cell in a hypotonic solution A) is turgid. B) lyses. C) shrivels. D) wilts. E) is flaccid.

A

Which of the following statements is true among all types of passive diffusion? A) Proteins are needed to transport molecules across the membrane. B) The concentration gradient is the driving force. C) Only small polar molecules are able to cross the plasma membrane. D) Only small nonpolar molecules are able to cross the plasma membrane. E) Ions never cross the plasma membrane by passive transport.

B

White blood cells (WBCs) are more resistant to lysis than red blood cells (RBCs). When looking at a sample of blood for WBCs, would could you do to reduce interference from RBCs? A) Mix the blood in a salty solution to cause the RBCs to lyse. B) Mix the blood in an isotonic solution and allow the WBCs to float to the top. C) Mix the blood with a dye that stains the proteins in the cytoplasm. D) Mix the blood in a hypotonic solution, which will cause the RBCs to lyse. E) Mix the blood in a hypertonic solution, which will cause the RBCs to lyse.

D

You are adrift in the Atlantic Ocean, and, being thirsty, drink the surrounding seawater. As a result, A) you quench your thirst. B) your cells lyse, due to the excessive intake of salt. C) your cells become turgid. D) you dehydrate yourself. E) your cells lyse from excessive water intake.

D

All cells are enclosed by a plasma membrane that is similar in ________ and ________. A) thickness . . . composition B) permeability . . . content C) proteins . . . lipids D) lucidity . . . texture E) structure . . . function

E

If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference? A) the expulsion of water by the plant cell's central vacuole B) the relative impermeability of the plant cell membrane to water C) the relative impermeability of the plant cell wall to water D) the fact that plant cells are isotonic to tap water E) the relative inelasticity and strength of the plant cell wall

E

A major function of glycoproteins and glycolipids in the cell membrane is to A) glue cells together to form tissues. B) allow the cells of an embryo to sort themselves into tissues and organs. C) attach the cell membrane to the cytoskeleton. D) help the cell resist swelling. E) help the cell retain its shape.

B

Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following processes could be responsible for its secretion? A) endocytosis B) exocytosis C) diffusion D) pinocytosis E) passive transport

B

Which of the following is a typical feature of an ATP-driven active transport mechanism? A) The transport protein must cross to the correct side of the membrane before the solute can bind to it. B) The solute must be phosphorylated before it can bind to the transport protein. C) The transport protein is irreversibly phosphorylated as transport takes place. D) The transport protein catalyzes the conversion of ADP to ATP. E) The solute moves against the concentration gradient.

E

In a hypotonic solution, an animal cell will A) lyse. B) experience turgor. C) neither gain nor lose water. D) shrivel. E) lose water.

A

In the lab, you use a special balloon that is permeable to water, but not sucrose, to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur? A) Water will leave the balloon. B) Water will enter the balloon. C) Sucrose will leave the balloon. D) Sucrose will enter the balloon. E) Sucrose and water will pass across the balloon simultaneously.

A

Many of the enzymes that control a deep-sea firefly squid's ability to produce light energy from chemical energy are located A) in membranes. B) in the nucleus. C) within chloroplasts. D) outside of cells. E) within mitochondria.

A

Osmosis can be defined as A) the diffusion of water. B) the diffusion of nonpolar molecules. C) active transport. D) the diffusion of a solute. E) endocytosis.

A

Relaying a message from a membrane receptor to a molecule that performs a specific function within a cell is called A) signal transduction. B) inhibition. C) competition. D) self-recognition. E) selective permeability.

A

Small, nonpolar, hydrophobic molecules such as fatty acids A) easily pass through a membrane's lipid bilayer. B) very slowly diffuse through a membrane's lipid bilayer. C) require transport proteins to pass through a membrane's lipid bilayer. D) are actively transported across cell membranes. E) usually enter the cell via endocytosis.

A

When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will A) exhibit a net movement to the side with lower water concentration. B) exhibit a net movement to the side with higher water concentration. C) exhibit a net movement to the side with lower solute concentration. D) exhibit an equal movement in both directions across the membrane. E) not cross the membrane.

A

Which of the following processes could result in the net movement of a substance into a cell, if the substance is more concentrated in the cell than in the surroundings? A) active transport B) facilitated diffusion C) diffusion D) osmosis E) passive transport.

A

Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment A) is isotonic to the protozoan. B) is hypotonic to the protozoan. C) is contaminated with pollutants. D) contains a higher concentration of solutes than the protozoan. E) is hypertonic to the protozoan.

B

The cholesterol associated with animal cell membranes A) is attached to membrane proteins and extends into the watery environment surrounding the cell. B) helps to stabilize the cell membrane at body temperature. C) makes the cell membrane fluid at room temperature. D) is an abnormality resulting from a diet high in cholesterol. E) helps solidify the membranes when the room temperature is below freezing.

B

Which characteristic promoted the utilization of lipids as the first cell membrane? A) spontaneous degradation of the intracellular environment B) self-assembly into a simple membrane C) ability to form an impermeable membrane D) formation of a semi-solid membrane E) utilization of the hydrophilic nature of lipids

B

Membrane phospholipids A) have hydrophobic heads that face the center of the membrane and are shielded from water. B) have hydrophilic tails that face outward and are exposed to water. C) often have "kinks" in their tails caused by the presence of a double bond between carbons. D) remain fluid because they are tightly packed against one another. E) form impermeable layers for cells

C

When physicians perform an organ transplant, they choose a donor whose tissues match those of the recipient as closely as possible. Which of the following cell components are being matched? A) plasma membrane phospholipids B) plasma membrane proteins C) cell-surface carbohydrates D) plasma membrane cholesterols E) cytoskeletal elements

C

Which of the following statements regarding active transport is false? A) Active transport uses ATP as an energy source. B) Active transport can move solutes up a concentration gradient. C) Active transport requires the cell to expend energy. D) Active transport is driven by the concentration gradient. E) Active transport is necessary to allow nerves to function properly.

D

Which of the following statements regarding diffusion is false? A) Diffusion is a result of the kinetic energy of atoms and molecules. B) Diffusion is driven by concentration gradients. C) Diffusion requires no input of energy into the system. D) Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated. E) Diffusion occurs even after equilibrium is reached and no net change is apparent.

D

Oxygen crosses a plasma membrane by A) osmosis. B) phagocytosis. C) active transport. D) pinocytosis. E) passive transport.

E

The fluid mosaic model describes the plasma membrane as consisting of A) a phospholipid bilayer with embedded carbohydrates. B) two layers of phospholipids with protein sandwiched between them. C) a protein bilayer with embedded phospholipids. D) carbohydrates, proteins, and phospholipids that can drift in the membrane. E) individual proteins and phospholipids that can drift in a phospholipid bilayer.

E

The molecules responsible for membrane transport are A) steroids. B) ATP. C) phospholipids. D) carbohydrates. E) proteins.

E

The process of a white blood cell engulfing a bacterium is A) osmosis. B) diffusion. C) receptor-mediated endocytosis. D) pinocytosis. E) phagocytosis.

E

In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the balloon is ________ relative to the solution in the beaker. A) isotonic B) hypotonic C) hypertonic D) hydrophobic E) hydrophilic

B

Most of the functions of a cell membrane are performed by A) glycolipids. B) proteins. C) phospholipids. D) cholesterol. E) nucleotides.

B

Phagocytosis is to eating as pinocytosis is to A) osmosis. B) drinking. C) chewing. D) hydrolysis. E) lysis.

B

Plasma membranes are selectively permeable. This means that A) anything can pass into or out of a cell as long as the membrane is intact and the cell is healthy. B) the plasma membrane allows some substances to enter or leave a cell more easily than others. C) glucose cannot enter the cell. D) cholesterol cannot enter the cell. E) plasma membranes must be very thick.

B

Cells acquire LDLs by A) osmosis. B) diffusion. C) receptor-mediated endocytosis. D) pinocytosis. E) phagocytosis.

C

Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of A) exocytosis. B) phagocytosis. C) passive transport. D) active transport. E) endocytosis.

C

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient. A) energy and transport proteins . . . down B) energy . . . down C) transport proteins . . . down D) energy and transport proteins . . . against E) transport proteins . . . against

C

Which of the following statements regarding membrane function is false? A) The plasma membrane forms a selective barrier around the cell. B) The plasma membrane plays a role in signal transduction. C) The plasma membrane has receptors for chemical messages. D) The plasma membrane is the control center of the cell. E) The plasma membrane is involved in self-recognition.

D

Which of the following substances would have the most trouble crossing a biological membrane by diffusing through the lipid bilayer? A) H2O B) O2 C) CO2 D) Na+ E) a small, nonpolar molecule such as butane (C4H10)

D

Which of the following processes can move a solute against its concentration gradient? A) osmosis B) passive transport C) diffusion D) facilitated diffusion E) active transport

E

Which of the following statements regarding membrane protein function is false? A) Membrane proteins serve as enzymes. B) Membrane proteins act as receptors to molecules like hormones. C) Membrane proteins provide cellular identification tags. D) Membrane proteins form junctions between cells. E) Membrane proteins transfer genetic information to the cytoplasm.

E