Q: During photosynthesis, plants convert carbon dioxide and water into carbohydrates. Which of the following equations correctly represents this process?

$6CO_2 + 6H_2O + \text{sunlight} \rightarrow (CH_2O)_6 + 6O_2$

Question 1

Which of the following best describes the general molecular formula for carbohydrates?

Accepted Answer

$C_nH_{2n}O_n$

Question 2

A biochemist is analyzing a sugar and finds that its carbonyl group is located at the end of the carbon chain. What type of sugar is this?

Accepted Answer

Aldose

Question 3

Which of the following structural features is NOT a way in which monosaccharides can differ from one another?

Accepted Answer

Type of glycosidic linkage

Question 4

Which of the following best explains why cellulose is a good structural material in plant cell walls?

Accepted Answer

It forms linear strands with hydrogen bonds between adjacent strands, making it strong and insoluble.

Question 5

Which of the following statements about glycosidic linkages is correct?

Accepted Answer

They are formed by condensation reactions between two hydroxyl groups.

Question 6

A patient is unable to digest starch but can digest cellulose. Which enzyme is most likely missing in this patient?

Accepted Answer

Amylase

Question 7

Which of the following best distinguishes chitin from cellulose?

Accepted Answer

Chitin is composed of N-acetylglucosamine monomers, while cellulose is composed of glucose monomers.

Question 8

Which of the following best explains why starch and glycogen are good for energy storage, while cellulose is not?

Accepted Answer

Starch and glycogen have a-glycosidic linkages that are easily hydrolyzed, while cellulose has b-glycosidic linkages that are difficult to break.

Question 9

Which of the following bonds in carbohydrates has the highest potential energy?

Accepted Answer

Carbon-hydrogen (C-H) bonds

Question 10

A scientist is studying a polysaccharide that is highly branched and found in animal muscle cells. Which polysaccharide is this most likely to be?

Accepted Answer

Glycogen

Question 11

Which of the following is a function of glycoproteins and glycolipids on the cell surface?

Accepted Answer

They play a key role in cell-cell recognition and signaling.

Question 12

Which of the following best describes the difference between amylose and amylopectin?

Accepted Answer

Amylose is unbranched, while amylopectin is branched due to a-1,6-glycosidic linkages.

Question 13

Which of the following statements about peptidoglycan is correct?

Accepted Answer

It is a structural polysaccharide found in bacterial cell walls, with parallel strands cross-linked by peptide bonds.

Question 14

Which of the following best explains why most organisms cannot digest cellulose?

Accepted Answer

They lack enzymes that can hydrolyze b-1,4-glycosidic linkages.

Question 15

During photosynthesis, plants convert carbon dioxide and water into carbohydrates. Which of the following equations correctly represents this process?

Accepted Answer

$6CO_2 + 6H_2O + 	ext{sunlight} ightarrow (CH_2O)_6 + 6O_2$

Question 16

Which of the following is a direct consequence of the ring structure of glucose in aqueous solution?

Accepted Answer

It can exist in two forms, alpha and beta, which affect the properties of polysaccharides formed.

Question 17

A researcher discovers a new polysaccharide with every other monomer flipped and b-1,4-glycosidic linkages. Which of the following is it most likely to be?

Accepted Answer

Chitin

Question 18

Which of the following best explains why carbohydrates are a good source of energy compared to carbon dioxide?

Accepted Answer

Carbohydrates have more C-H and C-C bonds, which have higher potential energy than the C=O bonds in CO$_2$.

Question 19

Which of the following enzymes is responsible for hydrolyzing a-glycosidic linkages in glycogen?

Accepted Answer

Phosphorylase

Chapter 5: An Introduction to Carbohydrates

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