Chapter 5 MasteringBiology

Which statement best describes phagocytosis?

A cell engulfs a particle by wrapping pseudopodia around it and packaging it within a vacuole.

Which of the following is an accurate comparison of active transport and facilitated diffusion?

Active transport moves solutes against their concentration gradient; facilitated diffusion moves substances down their concentration gradient.

Which of these statements describes what occurs in facilitated diffusion?

Facilitated diffusion of solutes occurs through protein pores in the membrane.

Antibiotics - for example, penicillin - cannot be used to treat viral infections, such as the common cold. Why?

Antibiotics inhibit enzymes that are essential to the survival of bacteria only.

Green olives may be preserved in brine, which is a 20-30% salt solution. How does this method prevent contamination by microorganisms?

Bacteria can't survive in a hypertonic solution because they lose water.

Taq polymerase is an enzyme isolated from the organism Thermophilus aquaticus. This organism has been found living in the hot springs of Yellowstone National Park. This enzyme is used to copy human DNA from crime scenes. Most reactions are performed at ranges similar to those of the human body; however, what considerations should be made for optimum use of this enzyme?

The temperature should be raised.

Which of these is exhibiting kinetic energy?

a space station orbiting Earth

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?

cellular respiration

During enzymatic reactions, substrates are converted to products. A property of enzymes that facilitates this reaction is that they are catalysts and therefore _____.

change the rate of a reaction without being consumed by the reaction

The phosphorylation of ADP to form ATP is an _____ reaction that _____ energy.

endergonic ... requires an input of

"Conservation of energy" refers to the fact that _____.

energy cannot be created or destroyed but can be converted from one form to another

When considering the formation of membranes, they __________.

form spontaneously in aqueous environments

Which of these are by-products of cellular respiration?

heat and water

What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule?

hydrolysis

The mechanism of enzyme action is to _____.

lower the energy of the activation of a reaction

What name is given to the process by which water crosses a selectively permeable membrane?

osmosis

The plasma membrane is selectively permeable. Which of the following can pass freely through the membrane with no assistance?

oxygen and carbon dioxide

Chemical energy is a form of _____ energy.

potential

The molecules responsible for membrane transport are

proteins.

When placed in a hypotonic environment, where the solute concentration is below that of the cell, a houseplant will _____.

remain standing upright

The lipids in a cell membrane are arranged _____.

so that the nonpolar parts of two lipids point toward each other

Succinylcholine is structurally almost identical to acetylcholine, but if combined with the enzyme that normally hydrolyzes acetylcholine, the enzyme is no longer able to hydrolyze acetylcholine. This suggests that _____.

succinylcholine must be a competitive inhibitor of acetylcholine

What controls the direction of a molecule, such as oxygen, involved in passive transport?

the direction of the oxygen concentration gradient

The active site of an enzyme is

the region of an enzyme that attaches to a substrate.

What substance is transported by aquaporins?

water

Which of the following statements is true about passive transport?

Passive transport requires no expenditure of cellular energy.