Q: Animals can digest starch but not cellulose. What is the main reason for this difference?

Cellulose has $eta$-glycosidic linkages, which cannot be broken down by animal enzymes.

Q: A patient is unable to digest certain plant materials such as celery and lettuce. Which polysaccharide is most likely responsible for this, and why?

Cellulose, because humans lack enzymes to break $eta$-glycosidic linkages.

Question 1

Which of the following statements best describes a dehydration reaction in the synthesis of biological macromolecules?

Accepted Answer

It joins two monomers by removing a water molecule, forming a covalent bond.

Question 2

Which of the following is NOT considered a true polymer among the four major classes of biological macromolecules?

Accepted Answer

Lipids

Question 3

A student is studying the structure of glucose and fructose. Both have the same molecular formula $C_6H_{12}O_6$, but differ in the position of their carbonyl group. What type of isomers are glucose and fructose?

Accepted Answer

Structural isomers

Question 4

Which polysaccharide is the most abundant organic compound on Earth and serves as a major structural component in plant cell walls?

Accepted Answer

Cellulose

Question 5

Animals can digest starch but not cellulose. What is the main reason for this difference?

Accepted Answer

Cellulose has $eta$-glycosidic linkages, which cannot be broken down by animal enzymes.

Question 6

Which of the following best describes the structure of a fat (triglyceride) molecule?

Accepted Answer

Three fatty acids joined to a glycerol by ester linkages

Question 7

Which type of fatty acid contains one or more double bonds in its hydrocarbon chain, resulting in a kinked structure?

Accepted Answer

Unsaturated fatty acid

Question 8

During digestion, which chemical process breaks down polymers into monomers?

Accepted Answer

Hydrolysis

Question 9

Which of the following is a structural polysaccharide found in the exoskeletons of arthropods and the cell walls of fungi?

Accepted Answer

Chitin

Question 10

A biologist is analyzing a sample and finds a molecule composed of a long chain of amino acids. Which type of macromolecule is this?

Accepted Answer

Protein

Question 11

Which of the following best explains why lipids are hydrophobic?

Accepted Answer

They contain many nonpolar hydrocarbon bonds and few polar oxygen bonds.

Question 12

Which of the following is the correct general formula for a monosaccharide?

Accepted Answer

$C_nH_{2n}O_n$ where $n$ is typically 3-7

Question 13

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes are specialized proteins that speed up chemical reactions by lowering activation energy.

Question 14

Which process is responsible for the formation of glycosidic linkages between monosaccharides?

Accepted Answer

Dehydration reaction

Question 15

A patient is unable to digest certain plant materials such as celery and lettuce. Which polysaccharide is most likely responsible for this, and why?

Accepted Answer

Cellulose, because humans lack enzymes to break $eta$-glycosidic linkages.

Question 16

Which of the following is a correct description of a polymer?

Accepted Answer

A molecule consisting of similar or identical building blocks called monomers joined by covalent bonds.

Question 17

Which of the following is a storage polysaccharide found in animal cells, especially in the liver and muscle?

Accepted Answer

Glycogen

Question 18

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

Accepted Answer

Aldose sugars have a carbonyl group at the end of the carbon chain, while ketose sugars have it within the chain.

Question 19

Which of the following is a correct example of a dehydration reaction in biological systems?

Accepted Answer

Formation of a peptide bond between two amino acids, releasing a water molecule.

Question 20

Which of the following statements about the diversity of biological macromolecules is correct?

Accepted Answer

The diversity of macromolecules arises from the arrangement of a limited number of monomers into various polymers.

Structure and Function of Large Biological Molecules

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