Question 1

Which of the following statements best explains why cellulose cannot be digested by humans, while starch can?

Accepted Answer

Cellulose contains $$ \beta -1$$,4 glycosidic bonds, which human digestive enzymes cannot hydrolyze, while starch contains $$ \alpha -1$$,4 and $$ \alpha -1$$,6 glycosidic bonds that can be broken down.

Question 2

A disaccharide is formed when two monosaccharides are joined by a glycosidic bond. Which reaction type is responsible for this bond formation?

Accepted Answer

Condensation (dehydration synthesis)

Question 3

Which of the following best describes the difference between a nucleoside and a nucleotide?

Accepted Answer

A nucleoside contains a pentose sugar and a nitrogenous base, while a nucleotide contains a pentose sugar, a nitrogenous base, and a phosphate group.

Question 4

Which of the following is a correct representation of the general formula for carbohydrates?

Accepted Answer

$$C_nH_{2n}O_n$$

Question 5

Which of the following statements about DNA and RNA is CORRECT?

Accepted Answer

DNA contains deoxyribose as its pentose sugar, while RNA contains ribose.

Question 6

Which of the following best describes the antiparallel nature of DNA strands?

Accepted Answer

One strand runs 5' to 3', and the other runs 3' to 5'.

Question 7

Which of the following is TRUE regarding the base pairing in DNA?

Accepted Answer

Guanine pairs with cytosine via three hydrogen bonds.

Question 8

A mutation replaces a cytosine with a thymine in a DNA strand. Which of the following is a possible consequence during DNA replication?

Accepted Answer

The mutated thymine will pair with adenine, potentially causing a point mutation in the next generation.

Question 9

Which of the following best explains why glycogen is a more efficient energy storage molecule in animals compared to amylose?

Accepted Answer

Glycogen has more frequent branching ($$ \alpha -1$$,6 linkages), allowing for rapid hydrolysis and release of glucose.

Question 10

Which of the following codons signals the start of translation in mRNA?

Accepted Answer

AUG

Question 11

Which of the following best describes the role of tRNA during translation?

Accepted Answer

tRNA serves as an adaptor molecule that links a specific amino acid to its corresponding codon on mRNA.

Question 12

Which of the following is a pyrimidine base found in RNA but not in DNA?

Accepted Answer

Uracil

Question 13

Which of the following statements about the phosphodiester bond in nucleic acids is CORRECT?

Accepted Answer

It forms between the phosphate group on C5' of one nucleotide and the C3' of the next nucleotide.

Question 14

Which of the following best describes an anomer in carbohydrate chemistry?

Accepted Answer

A stereoisomer that differs at the anomeric carbon formed during cyclization of a monosaccharide.

Question 15

Which of the following is a correct description of the difference between amylose and amylopectin?

Accepted Answer

Amylose is a straight-chain polymer of $$ \alpha -$$glucose, while amylopectin is a branched polymer of $$ \alpha -$$glucose.

Question 16

Which of the following is a function of DNA that distinguishes it from RNA?

Accepted Answer

DNA stores genetic information and passes it from parent to offspring.

Question 17

Which of the following best explains why the major groove of DNA is important for protein binding?

Accepted Answer

The major groove exposes more base pairs, allowing proteins to 'read' the DNA sequence more easily.

Question 18

Which of the following best describes the process of glycolysis?

Accepted Answer

It is the first stage of cellular respiration, converting glucose to pyruvate and producing energy.

Question 19

Which of the following is a correct statement about the structure of tRNA?

Accepted Answer

tRNA contains unusual bases that form loops, allowing it to recognize specific codons on mRNA.

Carbohydrates, Nucleosides, and Nucleotides: Structure and Function

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