Question 1

Which of the following amino acids has a negatively charged R group at physiological pH?

Accepted Answer

Aspartic acid

Question 2

In a Fischer projection, how are the D and L isomers of amino acids distinguished?

Accepted Answer

By the orientation of the amino group on the right (D) or left (L) of the chiral carbon

Question 3

Which of the following best describes the peptide bond in proteins?

Accepted Answer

It is a covalent bond formed between the carboxyl group of one amino acid and the amino group of another.

Question 4

Which of the following is a function of lipids in biological membranes?

Accepted Answer

They provide structural support and regulate membrane fluidity.

Question 5

Which of the following is true about the orientation of wedges and dashes in a Fischer projection?

Accepted Answer

Wedges point toward the viewer, dashes point behind the plane of paper.

Question 6

Which process converts pyruvate to lactic acid under anaerobic conditions?

Accepted Answer

Fermentation

Question 7

Which of the following is a major function of the sodium-potassium pump in nerve cells?

Accepted Answer

To maintain the resting membrane potential by transporting Na+ out and K+ into the cell

Question 8

Which of the following statements about the amide plane in proteins is correct?

Accepted Answer

It is formed by the peptide bond and restricts rotation around the bond.

Question 9

Which pathway is responsible for the synthesis of glucose from non-carbohydrate precursors?

Accepted Answer

Gluconeogenesis

Question 10

Which of the following is a consequence of a defect in the beta-oxidation pathway?

Accepted Answer

Impaired breakdown of fatty acids and reduced ATP production

Question 11

Which of the following best describes the role of the carboxyl group in amino acids?

Accepted Answer

It acts as an acid and donates protons.

Question 12

Which of the following is true about the secondary structure of proteins?

Accepted Answer

It is stabilized by hydrogen bonds between backbone atoms.

Question 13

Which of the following is a negatively charged amino acid at physiological pH?

Accepted Answer

Glutamic acid

Question 14

Which of the following is the correct formula for the net ATP yield from one cycle of the citric acid cycle?

Accepted Answer

$$1$$

Question 15

Which of the following is a function of cholesterol in cell membranes?

Accepted Answer

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

Question 16

Which of the following is true about the structure of aspartic acid?

Accepted Answer

It contains a carboxyl group in its side chain.

Question 17

Which of the following is the correct general formula for an amino acid?

Accepted Answer

$$\mathrm{NH_2${-}CHR{-}COOH}$$

Question 18

Which of the following is a result of protein misfolding in cells?

Accepted Answer

Formation of insoluble aggregates that can cause diseases

Question 19

Which of the following is true about the alpha carbon in amino acids?

Accepted Answer

It is the central carbon atom bonded to the amino group, carboxyl group, hydrogen, and R group.

Question 20

Which of the following is the correct equation for the conversion of pyruvate to lactate?

Accepted Answer

$$\mathrm{Pyruvate + NADH + H^+ \rightarrow Lactate + NAD^+}$$

Amino Acids, Isomerism, and Lipids: Biochemistry Study Notes

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