Bio 160 Ch. 5 Quiz

Which of the following statements regarding active transport is false? Active transport is driven by the concentration gradient. Active transport uses ATP as an energy source. Active transport can move a solute against its concentration gradient. Active transport requires the cell to expend energy.

Active transport is driven by the concentration gradient.

Which of the following statements regarding enzyme function is false? Enzymes are very specific for certain substrates. Enzymes emerge unchanged from the reactions they catalyze. Enzymes are used up when they catalyze a chemical reaction, so must be synthesized for each new chemical reaction. An enzyme's function depends on its three-dimensional shape.

Enzymes are used up when they catalyze a chemical reaction, so must be synthesized for each new chemical reaction.

Which of the following statements regarding enzymes is true? All enzymes depend on protein cofactors to function. Enzymes catalyze specific reactions. An enzyme's function is unaffected by changes in pH. Enzymes are inorganic.

Enzymes catalyze specific reactions

What is the basic difference between exergonic and endergonic reactions? Exergonic reactions involve the breaking of bonds; endergonic reactions involve the formation of bonds. Exergonic reactions involve ionic bonds; endergonic reactions involve covalent bonds. Exergonic reactions release energy; endergonic reactions absorb it. In exergonic reactions, the reactants have less chemical energy than the products; in endergonic reactions, the opposite is true.

Exergonic reactions release energy; endergonic reactions absorb it.

Which of the following statements about the ATP molecule is true? It contains the sugar glucose. It releases energy when one phosphate group leaves ATP. Extremely stable bonds link the second and third phosphate groups. It contains five phosphate groups.

It releases energy when one phosphate group leaves ATP.

Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing chemical energy into potential energy. chemical energy into kinetic energy. kinetic energy into thermal energy. kinetic energy into potential energy.

chemical energy into kinetic energy.

Which of the following statements regarding membrane function is false? The plasma membrane has receptors for chemical messages. The plasma membrane forms a selective barrier around the cell. The plasma membrane is the control center of the cell. The plasma membrane plays a role in signal transduction

The plasma membrane is the control center of the cell

Which of the following substances could be a cofactor? a protein a zinc atom a ribosome a polypeptide

a zinc atom

Substrates bind to an enzyme's ________ site. allosteric inhibitory phosphate active

active

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

allow the cells of an embryo to sort themselves into tissues and organs.

Aquaporins allow for the active transport of water. allow water to cross the plasma membrane via facilitated diffusion. are found in all cells. allow water to cross the plasma membrane against its concentration gradient

allow water to cross the plasma membrane via facilitated diffusion.

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? plasma membrane cholesterols plasma membrane phospholipids plasma membrane proteins cell-surface carbohydrates

cell-surface carbohydrates

Small, nonpolar, hydrophobic molecules such as fatty acids very slowly diffuse through a membrane's lipid bilayer. easily pass through a membrane's lipid bilayer. are actively transported across cell membranes. require transport proteins to pass through a membrane's lipid bilayer.

easily pass through a membrane's lipid bilayer

When a cell uses chemical energy to perform work, it uses the energy released from a(n) ________ reaction to drive a(n) ________ reaction. exergonic . . . spontaneous endergonic . . . exergonic exergonic . . . endergonic spontaneous . . . exergonic

exergonic . . . endergonic

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? diffusion pinocytosis exocytosis endocytosis

exocytosis

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

helps to stabilize the cell membrane at body temperature

When an enzyme catalyzes a reaction, it is used once and discarded. it lowers the activation energy of the reaction. it raises the activation energy of the reaction. it acts as a reactant.

it lowers the activation energy of the reaction.

In a hypotonic solution, an animal cell will experience turgor. neither gain nor lose water. lyse. shrivel.

lyse

Most of a cell's enzymes are amino acids. carbohydrates. lipids. proteins.

proteins

Cells acquire LDLs by receptor-mediated endocytosis. pinocytosis. phagocytosis. diffusion.

receptor-mediated endocytosis.

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

the relative inelasticity and strength of the plant cell wall

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient. energy and transport proteins . . . down transport proteins . . . against transport proteins . . . down energy and transport proteins . . . against

transport proteins . . . down