Question 1

Which of the following functional groups is most likely to participate in hydrogen bonding within proteins, thereby stabilizing secondary structure?

Accepted Answer

Amide group ($$\mathrm{$$CONH_2$$})$$

Question 2

A microorganism that obtains its carbon from organic compounds and its energy from light is best classified as which of the following?

Accepted Answer

Photoheterotroph

Question 3

Which of the following best explains why water is considered the 'solvent of life'?

Accepted Answer

Water's polarity and ability to form hydrogen bonds enable it to dissolve a wide range of biological molecules.

Question 4

Which of the following is a colligative property of water that is crucial for maintaining cellular homeostasis?

Accepted Answer

Boiling point elevation

Question 5

A buffer solution is prepared using acetic acid and its conjugate base. If the pH of the solution is equal to the pKa of acetic acid, what is the ratio of acetate ($$\mathrm{A^-}) to $$acetic acid ($$\mathrm{HA}) $$according to the Henderson-Hasselbalch equation?

Accepted Answer

1:1

Question 6

Which of the following best describes what happens to the bicarbonate buffer system in the blood when the concentration of $$\mathrm{CO_2$}$$ increases?

Accepted Answer

The pH decreases as more carbonic acid is formed.

Question 7

Which term describes a reaction that absorbs heat from its surroundings?

Accepted Answer

Endothermic

Question 8

Given the Gibbs Free Energy equation $$\Delta G = \Delta H - T\Delta S$$, what will happen to $$\Delta G if$$ $$\Delta H is $$negative, $$\Delta S is $$positive, and temperature increases?

Accepted Answer

$$\Delta G$$ becomes more negative.

Question 9

Which property of high-energy phosphate bonds (such as in ATP) is primarily responsible for their ability to release energy upon hydrolysis?

Accepted Answer

Resonance stabilization of products

Question 10

At physiological pH ($$\sim7.4$$), which amino acid is most likely to be positively charged?

Accepted Answer

Lysine (K)

Question 11

Which linkage forms the primary structure of proteins?

Accepted Answer

Peptide bond

Question 12

A protein is purified using ion exchange chromatography. If the protein has a net negative charge at pH 7, which type of column should be used?

Accepted Answer

Anion exchange column

Question 13

Which amino acid has a side chain that restricts rotation around the peptide bond, affecting protein secondary structure?

Accepted Answer

Proline (P)

Question 14

If a protein has a pI of 5.5, what will be its net charge at pH 8.0?

Accepted Answer

Negative

Question 15

Which of the following best describes the trend of hydrophobicity among amino acids?

Accepted Answer

Amino acids with aromatic or aliphatic side chains are generally more hydrophobic.

Question 16

During protein purification, which method would best separate proteins based on their size?

Accepted Answer

Size-exclusion chromatography

Question 17

A solution contains 0.1 M lactic acid ($$\mathrm{HA}) $$and 0.1 M lactate ($$\mathrm{A^-}). If $$the pKa of lactic acid is 3.86, what is the pH of the solution using the Henderson-Hasselbalch equation?

Accepted Answer

pH = 3.86

Question 18

Which of the following forces is most important for stabilizing the tertiary structure of a globular protein in aqueous solution?

Accepted Answer

Hydrophobic interactions

Question 19

A patient with respiratory acidosis has elevated $$\mathrm{CO_2$}$$ levels. Which buffer system in the body is most directly affected?

Accepted Answer

Bicarbonate buffer system

Question 20

Which of the following scenarios would result in an increase in the boiling point of water, according to colligative properties?

Accepted Answer

Adding sodium chloride to water

Biochemistry 5201 Exam 1 Study Guide: Foundations, Water, Amino Acids, Protein Structure, and Techniques

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