Question 1

Which of the following correctly describes the glycosidic linkage in amylopectin?

Accepted Answer

It contains both $$\alpha(1\rightarrow4)$$ and $$\alpha(1\rightarrow6)$$ linkages, resulting in branching.

Question 2

Which enzyme is required to hydrolyze $$\beta(1\rightarrow4)$$ glycosidic bonds in cellulose, and why can't humans digest cellulose?

Accepted Answer

Cellulase; humans lack this enzyme to hydrolyze $$\beta(1\rightarrow4)$$ bonds.

Question 3

Which of the following is a nucleotide, and what are its components?

Accepted Answer

AMP; base, sugar, and phosphate group

Question 4

What is the difference between DNA and RNA at the 2' position of the sugar?

Accepted Answer

DNA has a hydrogen, RNA has a hydroxyl group.

Question 5

Which base pairing is correct in nucleic acids?

Accepted Answer

Adenine pairs with thymine via two hydrogen bonds.

Question 6

Which of the following amino acids is basic and positively charged at physiological pH?

Accepted Answer

Lysine

Question 7

What is the product of peptide bond hydrolysis under acidic conditions?

Accepted Answer

A mixture of free amino acids

Question 8

Which reagent is commonly used to cleave disulfide bonds in proteins?

Accepted Answer

Mercaptoethanol

Question 9

During solid-phase peptide synthesis, which protecting group is commonly used for the amino terminus?

Accepted Answer

Boc (tert-butyloxycarbonyl)

Question 10

Which of the following is a saturated fatty acid?

Accepted Answer

Palmitic acid

Question 11

What is the main structural difference between triglycerides and phospholipids?

Accepted Answer

Triglycerides have three fatty acids, phospholipids have two fatty acids and a phosphate group.

Question 12

Which vitamin is fat-soluble and important for vision?

Accepted Answer

Vitamin A

Question 13

Which process is used to make margarine from vegetable oils?

Accepted Answer

Hydrogenation

Question 14

Which of the following statements about cholesterol is correct?

Accepted Answer

It is a steroid and a precursor for hormones.

Question 15

Which type of polymerization involves the formation of a polymer and a small molecule byproduct such as water?

Accepted Answer

Step-growth (condensation) polymerization

Question 16

What is the effect of increasing the glass transition temperature ($$T_g) in $$polymers?

Accepted Answer

Polymers become brittle and break more easily below $$T_g.$$

Question 17

Which of the following is a property of natural rubber?

Accepted Answer

It is elastic and can be vulcanized to improve strength.

Question 18

Which amino acid can form disulfide bonds, stabilizing protein structure?

Accepted Answer

Cysteine

Question 19

Which of the following reactions is used to synthesize esters from carboxylic acids and alcohols?

Accepted Answer

Esterification

Question 20

Which of the following statements about peptide bonds is correct?

Accepted Answer

Peptide bonds are formed between the carboxyl group of one amino acid and the amino group of another.

Organic Chemistry Review: Polysaccharides, Nucleic Acids, Amino Acids, Lipids, and Polymers

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