Chapter 4

_______ is life's primary source of energy. a. Food b. Water c. Sunlight d. ATP

Energy _______. a. cannot be created or destroyed b. can change from one form to another c. tends to disperse spontaneously d. all of the above

If we liken a chemical reaction to an energy hill, then an ______ reaction is an uphill run. a. energy-requiring b. energy-releasing c. ATP-assisted d. both a and \(c\)

______ are always changed by participating in a reaction. (Choose all that are correct.) a. Enzymes b. Cofactors c. Reactants d. Intermediates

Enzymes ______. a. are proteins, except for a few RNAs b. lower the activation energy of a reaction c. are changed by the reactions they catalyze d. a and b

Which of the following statements is not correct? A metabolic pathway _______. a. is a sequence of enzyme-mediated reactions b. may build or break down molecules c. generates heat d. can include an electron transfer chain e. none of the above

Diffusion is the movement of ions or molecules from a region where they are _______ (more/less) concentrated to another where they are _______ (more/less) concentrated.

Name one molecule that can readily diffuse across a lipid bilayer.Some sodium ions cross a cell membrane through transport

Some sodium ions cross a cell membrane through transport proteins that first must be activated by an energy boost. This is an example of _______. a. passive transport b. active transport c. facilitated diffusion d. a and c

Immerse a living cell in a hypotonic solution, and water will tend to ______. a. move into the cell b. move out of the cell c. show no net movement d. move in by endocytosis

Fluid pressure against a wall or cell membrane is called ______.

Vesicles form by ______. a. endocytosis b. exocytosis c. show no net movement d. move in by endocytosis

Match each term with its most suitable description. _____reactant _____enzyme _____first law _____product _____cofactor _____gradient _____phospholipid _____active transport _____phagocytosis a. assists enzymes b. there at reaction's end c. enters a reaction d. unchanged by participating in a reaction e. energy cannot be created or destroyed f. basis of diffusion g. important in membranes h. one cell engulfs another i. requires energy boost