Chapter 4

___________ is the main source of energy for the world of life. a. Food b. Water c. Sunlight d. ATP

Which of the following statements is not correct? a. Energy cannot be created or destroyed. b. Energy cannot change from one form to another. c. Energy tends to disperse spontaneously.

If we liken a reaction to an energy hill, then a reaction that __________ is an uphill run. a. requires energy b. releases energy c. runs backward d. uses an enzyme and a cofactor

In an energy-requiring reaction, activation energy is a bit like ___________. a. a burst of speed at the top of a reaction b. products coasting downhill c. a hill that reactants must climb

Enzymes _______ a. are proteins, except for a few RNAs b. lower the activation energy of a reaction c. are changed by participating in a reaction d. a and b

Name an environmental factor that influences enzyme function.

A metabolic pathway __________. a. may build or break down molecules b. generates heat c. can include an electron transfer chain d. all of the above

Which of the following statements is not correct? a. Some metabolic pathways are cyclic. b. Glucose can diffuse directly through a lipid bilayer. c. All coenzymes are cofactors. d. Osmosis is an example of diffusion.

A solute tends to diffuse from a region where it is __________ concentrated to another where it is __________ concentrated. a. more, less b. less, more

__________ cannot diffuse directly through a lipid bilayer. a. Water b. Gases c. Ions d. Nonpolar molecules

Immerse a human red blood cell in a hypotonic solution, and water __________. a. diffuses into the cell b. diffuses out of the cell c. shows no net movement d. moves in by endocytosis

Internal fluid pressure against a cell wall or membrane is called ___________. a. osmosis b. turgor pressure c. diffusion d. osmotic pressure

A transport protein requires ATP to pump sodium ions across a membrane. This is a case of __________. a. passive transport b. active transport c. facilitated diffusion d. osmosis

Vesicles form in ___________. a. endocytosis b. exocytosis c. phagocytosis d. all of the above

$$ \text {reactant } \quad \quad \text {a. assists enzymes} $$ $$ \text {phagocytosis} \quad \quad \text {b. forms at reaction's end} $$ $$ \text {first law of thermodynamics} \quad \quad \text {c. enters a reaction} $$ $$ \text {product} \quad \quad \text {d. currency in a cell's energy economy} $$ $$ \text {cofactor} \quad \quad \text {e. one cell "eats" another} $$ $$ \text {concentration gradient} \quad \quad \text {f. energy cannot be created or destroyed} $$ $$ \text {passive transport} \quad \quad \text {g. motivates diffusion} $$ $$ \text {cyclic pathway} \quad \quad \text {h. no energy input required} $$ $$ \text {ATP} \quad \quad \text {i. goes in circles} $$