$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Fully protonated: $$\mathrm{H}_3N^+\text{–}CH_2$\text{–}COOH$$

Question 1

Which property of carbon is MOST responsible for the diversity of biomolecules found in living organisms?

Accepted Answer

Its four valence electrons, allowing it to form up to four stable covalent bonds with other atoms

Question 2

Which of the following best describes the Central Dogma of Life?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 3

Amino acids are linked together in proteins by which type of bond, and what is released during this reaction?

Accepted Answer

Peptide bond; water

Question 4

Which of the following statements about noncovalent interactions in biological macromolecules is CORRECT?

Accepted Answer

They include hydrogen bonds, ionic interactions, van der Waals forces, and the hydrophobic effect.

Question 5

Which experiment provided evidence that amino acids could form under early Earth conditions, supporting the primordial soup hypothesis?

Accepted Answer

Miller and Urey's spark discharge experiment

Question 6

At physiological pH ($$pH = 7.4$$), what is the predominant form of a standard amino acid (excluding those with ionizable side chains)?

Accepted Answer

The amino group is protonated ($$-\mathrm{NH}_3^+) $$and the carboxyl group is deprotonated ($$-\mathrm{COO}^-$$), forming a zwitterion

Question 7

Which of the following best describes an anabolic pathway?

Accepted Answer

A pathway that consumes energy to build complex molecules from simpler ones

Question 8

Which of the following is TRUE regarding the isoelectric point ($$pI) of an $$amino acid?

Accepted Answer

It is the pH at which the amino acid has no net overall charge

Question 9

Which of the following is a real-world application of biochemistry in medicine?

Accepted Answer

Producing recombinant insulin for diabetes treatment

Question 10

Which of the following statements about the elements of life is CORRECT?

Accepted Answer

Carbon is more abundant in living organisms than in the rest of the universe.

Question 11

A solution contains glycine at $$pH = 1.0. $$Which form of glycine predominates?

Accepted Answer

Fully protonated: $$\mathrm{H}_3N^+	ext{–}CH_2$	ext{–}COOH$$

Question 12

Which of the following best explains why noncovalent interactions are crucial for protein function?

Accepted Answer

They allow proteins to fold into specific three-dimensional shapes necessary for biological activity.

Question 13

Which of the following is a correct statement about the behavior of amino acids in water?

Accepted Answer

The charge state of amino acids depends on the environmental pH.

Question 14

Which of the following is a polymer formed from amino acids?

Accepted Answer

Protein

Question 15

Which of the following best describes the role of carbon-based metabolites in cells?

Accepted Answer

They form the basis for polymeric machines, supramolecular structures, and information repositories.

Question 16

A patient’s blood pH drops to 6.8. What is the expected effect on the charge state of amino acids in their blood?

Accepted Answer

Carboxyl groups will be more likely to gain protons, becoming neutral.

Question 17

Which of the following is a trace element essential for life?

Accepted Answer

Iron

Question 18

Which of the following best describes the difference between covalent and noncovalent interactions in biomolecules?

Accepted Answer

Covalent bonds involve sharing electrons, while noncovalent interactions are weaker attractions that do not involve electron sharing.

Question 19

Which of the following is a correct example of a catabolic pathway?

Accepted Answer

Breakdown of glucose during cellular respiration

Question 20

Which of the following best explains why the C–C bond is important in biochemistry?

Accepted Answer

It is highly stable, allowing for the formation of long carbon chains and complex biomolecules.

Introduction to Biochemistry and Amino Acids: Foundations and Chemical Principles

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