Question 1

Which of the following statements best explains why tertiary amines have lower boiling points than primary amines of similar molecular weight?

Accepted Answer

Tertiary amines cannot form hydrogen bonds with themselves because they lack N-H bonds.

Question 2

A drug is formulated as an ammonium salt to improve its absorption in the body. Which property of ammonium salts is most responsible for this effect?

Accepted Answer

Ammonium salts are more soluble in water due to ionic interactions.

Question 3

Which of the following is the correct product of the acid hydrolysis of ethanamide ($$CH_3CONH_2) $$with hydrochloric acid?

Accepted Answer

$$CH_3COOH$$ \, (acetic\ acid) \, + \, NH_4Cl$

Question 4

Which of the following best describes the secondary structure of proteins?

Accepted Answer

It is the folding or coiling of short sections of the polypeptide, stabilized by hydrogen bonds between peptide groups in the backbone.

Question 5

Which of the following amines would be most soluble in water?

Accepted Answer

A primary amine with a short carbon chain

Question 6

What is the IUPAC name for the following compound: $$CH_3CH_2CH_2NH_2$$?

Accepted Answer

1-Propanamine

Question 7

Which of the following methods will NOT denature a protein?

Accepted Answer

Adding a small amount of neutral salt

Question 8

Which of the following is a heterocyclic amine found in DNA and RNA?

Accepted Answer

Purine

Question 9

What is the product of the base hydrolysis of N-methylpropanamide ($$CH_3CH_2CONHCH_3) $$with sodium hydroxide?

Accepted Answer

$$CH_3CH_2COO^- Na^+$$ \, (sodium\ propanoate) \, + \, CH_3NH_2$

Question 10

Which of the following amino acids can form an ion pair with glutamic acid at pH 7?

Accepted Answer

Arginine

Question 11

Which of the following is the correct structure for a peptide bond?

Accepted Answer

$$-CO-NH-$$

Question 12

Which of the following statements about protein denaturation is TRUE?

Accepted Answer

Denaturation disrupts the interactions that maintain the protein's structure, rendering it inactive.

Question 13

Which of the following is an example of an aromatic amine?

Accepted Answer

Aniline

Question 14

What is the effect of adding a strong acid to a solution of a primary amine?

Accepted Answer

The amine is converted to an ammonium salt.

Question 15

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

Accepted Answer

The arrangement of two or more polypeptide chains to form an active protein.

Question 16

Which of the following is a property of alkaloids?

Accepted Answer

They are naturally occurring amines with physiological effects.

Question 17

Which of the following is the correct IUPAC name for the amide formed from butanoic acid and ammonia?

Accepted Answer

Butanamide

Question 18

Which of the following changes will most likely disrupt disulfide bridges in a protein?

Accepted Answer

Addition of heavy metal ions such as lead or mercury

Question 19

Which of the following is the correct formula for the reaction of methylamine with hydrochloric acid?

Accepted Answer

$$CH_3NH_2 + HCl \rightarrow CH_3NH_3^+ Cl^-$$

Question 20

Which of the following best explains why beta sheets are strong structural elements in proteins and synthetic polymers?

Accepted Answer

Beta sheets are stabilized by extensive hydrogen bonding between parallel or antiparallel strands.

CH 18 STUDY NOTES

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