Question 1

Which of the following statements about starch and cellulose in plants is FALSE?

Accepted Answer

Cellulose tends to be more branched than starch.

Question 2

Which part of the polypeptide participates in the hydrogen bonds that stabilize secondary structure (such as alpha helices and beta sheets)?

Accepted Answer

Polypeptide backbone.

Question 3

Which of the following best describes an anabolic pathway?

Accepted Answer

A pathway that requires energy to build complex molecules from simpler ones.

Question 4

Which of the following is an example of a catabolic reaction in living organisms?

Accepted Answer

Cellular respiration breaking down glucose to produce ATP.

Question 5

Which statement about energy transformations in living organisms is correct?

Accepted Answer

All energy transformations increase the entropy of the universe.

Question 6

A chemical reaction has a $\Delta G$ of $-5$ kcal/mol. What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and will occur spontaneously.

Question 7

Which of the following best explains how ATP powers cellular work?

Accepted Answer

ATP hydrolysis releases energy that can be coupled to endergonic reactions.

Question 8

The hydrolysis of ATP to ADP and inorganic phosphate ($\mathrm{P_i}$) has a $\Delta G$ of $-7.3$ kcal/mol. What does this mean for the reaction?

Accepted Answer

It is a spontaneous reaction that releases energy.

Question 9

Which of the following is NOT a type of cellular work powered by ATP?

Accepted Answer

Passive diffusion of gases across the plasma membrane.

Question 10

How do enzymes speed up chemical reactions in biological systems?

Accepted Answer

By lowering the activation energy ($E_A$) required for the reaction.

Question 11

Which of the following statements about enzyme specificity is correct?

Accepted Answer

Enzymes are specific to their substrates due to the shape of their active site.

Question 12

A patient has a fever of 40°C. How might this affect the activity of most human enzymes?

Accepted Answer

Enzyme activity may decrease because the temperature is above the optimal range.

Question 13

Which of the following best describes the relationship between exergonic and endergonic reactions in cells?

Accepted Answer

Cells couple exergonic reactions to drive endergonic reactions using molecules like ATP.

Question 14

Which of the following is a correct statement about the regeneration of ATP in cells?

Accepted Answer

ATP is regenerated from ADP and $\mathrm{P_i}$ using energy from catabolic (exergonic) processes.

Question 15

A scientist adds a chemical to a reaction that specifically binds to the active site of an enzyme, blocking substrate binding. What type of molecule is this chemical?

Accepted Answer

A competitive inhibitor.

Question 16

Which of the following best explains why spontaneous (exergonic) reactions do not always occur rapidly in living cells?

Accepted Answer

They require enzymes to lower the activation energy barrier.

Question 17

Which of the following is true regarding the effect of pH on enzyme activity?

Accepted Answer

Each enzyme has an optimal pH at which it functions most efficiently.

Question 18

A metabolic pathway converts molecule A to molecule D in three steps, each catalyzed by a different enzyme. If enzyme 2 is inhibited, what will happen?

Accepted Answer

Molecule B will accumulate, and the pathway will stop at that point.

Question 19

Which of the following best describes the role of entropy ($S$) in biological systems according to the second law of thermodynamics?

Accepted Answer

Every energy transformation increases the entropy of the universe.

Question 20

A cell needs to move sodium ions against their concentration gradient. Which type of work is this, and how is it powered?

Accepted Answer

Transport work, powered by ATP hydrolysis.

General Biology Study Notes: Polysaccharides, Protein Structure, and Metabolism

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