Q: A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

$$[H^+] = 1 \times 10$$^{-4}$$ M

Question 1

Which of the following best explains why water is considered a good solvent for many biological molecules?

Accepted Answer

Water's polarity allows it to form hydrogen bonds with charged and polar molecules, making it an excellent solvent.

Question 2

A scientist discovers a new molecule that is amphipathic. Which of the following structures is this molecule most likely to help form in a cell?

Accepted Answer

A phospholipid bilayer, with hydrophilic heads facing outward and hydrophobic tails inward.

Question 3

Which of the following best describes the difference between competitive and allosteric inhibition of enzymes?

Accepted Answer

Competitive inhibitors bind to the active site, while allosteric inhibitors bind to a different site, changing the enzyme's shape.

Question 4

Which of the following equations correctly represents the relationship between free energy change ($$\Delta G$$), enthalpy ($$\Delta H$$), temperature ($$T$$), and entropy ($$\Delta S) in a $$chemical reaction?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 5

A patient is diagnosed with a genetic disorder that prevents the formation of quaternary protein structure. Which of the following would most likely be affected in this patient?

Accepted Answer

The ability of hemoglobin to transport oxygen efficiently.

Question 6

Which of the following best explains why cholesterol is important in animal cell membranes?

Accepted Answer

Cholesterol decreases membrane fluidity at high temperatures and increases it at low temperatures.

Question 7

Which of the following scenarios best illustrates the concept of energetic coupling in cells?

Accepted Answer

A cell uses the energy released from ATP hydrolysis to drive the synthesis of glucose from carbon dioxide.

Question 8

Which of the following statements about prokaryotic and eukaryotic cells is correct?

Accepted Answer

Eukaryotic cells have a nucleus, while prokaryotic cells lack a nucleus.

Question 9

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ M

Question 10

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids joined by peptide bonds.

Question 11

A cell is placed in a hypotonic solution. What is most likely to happen to the cell?

Accepted Answer

The cell will swell as water enters by osmosis.

Question 12

Which of the following is a property of saturated fatty acids compared to unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds and pack more tightly, making membranes less fluid.

Question 13

Which of the following best explains how enzymes speed up chemical reactions?

Accepted Answer

Enzymes lower the activation energy ($$E_a) $$required for a reaction to proceed.

Question 14

Which of the following is an example of passive transport across a cell membrane?

Accepted Answer

Oxygen diffusing from high to low concentration through the lipid bilayer.

Question 15

Which of the following statements about ATP is correct?

Accepted Answer

ATP stores energy in the bonds between its phosphate groups, which can be released during hydrolysis.

Question 16

A protein is exposed to high heat and extreme pH. Which level(s) of protein structure are most likely to be disrupted?

Accepted Answer

Secondary, tertiary, and quaternary structures are disrupted, but the primary structure may remain intact.

Question 17

Which of the following best describes an exergonic reaction?

Accepted Answer

A reaction that releases energy and has $$\Delta G \u003c 0.$$

Question 18

Which of the following is a function of the endoplasmic reticulum in eukaryotic cells?

Accepted Answer

Synthesis of proteins and lipids for the cell.

Question 19

A researcher adds a noncompetitive inhibitor to an enzyme-catalyzed reaction. What is the most likely effect on the reaction rate?

Accepted Answer

The maximum reaction rate ($$V_{max}) $$decreases, but the substrate can still bind to the active site.

General Biology Study Guide: Chemistry of Life, Proteins, Membranes, and Enzymes

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