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 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. phagocytosis d. all of the above

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