Question 1

Which of the following statements about the Diels-Alder reaction is CORRECT?

Accepted Answer

The reaction is a [4+2] cycloaddition between a diene and a dienophile.

Question 2

Which of the following best describes the regiochemistry of a Diels-Alder reaction between a diene with an electron-donating group (EDG) and a dienophile with an electron-withdrawing group (EWG)?

Accepted Answer

The EDG and EWG will be ortho or para to each other in the product.

Question 3

Which of the following is a requirement for a diene to participate in a Diels-Alder reaction?

Accepted Answer

The diene must be in the s-cis conformation.

Question 4

A carbohydrate with the formula $$C_5H_{10}O_5$ is classified as which of the following?

Accepted Answer

A pentose

Question 5

Which of the following statements about mutarotation is TRUE?

Accepted Answer

It is the change in optical rotation due to interconversion between anomers.

Question 6

Which of the following best describes an epimer?

Accepted Answer

A stereoisomer that differs at only one stereocenter.

Question 7

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 charge.

Question 8

Which of the following statements about the endo rule in the Diels-Alder reaction is CORRECT?

Accepted Answer

The endo product is favored due to secondary orbital interactions.

Question 9

Which of the following is a reducing sugar?

Accepted Answer

D-glucose

Question 10

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

Accepted Answer

The sequence of amino acids in the polypeptide chain.

Question 11

Which of the following reagents can oxidize an aldehyde to a carboxylic acid without oxidizing a primary alcohol?

Accepted Answer

$$Ag_2O$$

Question 12

Which of the following statements about the stereochemistry of the Diels-Alder reaction is TRUE?

Accepted Answer

The reaction is stereospecific; cis substituents on the dienophile remain cis in the product.

Question 13

Which of the following best describes the function of a protecting group in peptide synthesis?

Accepted Answer

It prevents unwanted reactions at specific functional groups.

Question 14

Which of the following is TRUE about the formation of a glycosidic bond in a disaccharide?

Accepted Answer

It involves the reaction of the anomeric carbon of one sugar with a hydroxyl group of another.

Question 15

Which of the following amino acids contains a thiol group in its side chain?

Accepted Answer

Cysteine

Question 16

A student treats D-glucose with $$NaBH_4. $$What is the major product?

Accepted Answer

D-glucitol (sorbitol)

Question 17

Which of the following best describes the difference between an aldose and a ketose?

Accepted Answer

An aldose contains an aldehyde group, while a ketose contains a ketone group.

Question 18

Which of the following is the correct order of increasing structural complexity in proteins?

Accepted Answer

Primary \u003c Secondary \u003c Tertiary \u003c Quaternary

Question 19

Which of the following is a correct statement about the Fischer projection of D-glucose?

Accepted Answer

The hydroxyl group on the penultimate carbon is on the right.

Question 20

Which of the following best describes the role of DCC (dicyclohexylcarbodiimide) in peptide synthesis?

Accepted Answer

It acts as a coupling agent to activate the carboxylic acid for amide bond formation.

Diels-Alder Reactions, Carbohydrates, and Amino Acids: Mini-Textbook Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard