Q: Cellulose is a polysaccharide that cannot be digested by most animals. What is the main reason for this?

Animals lack the enzyme to break the $eta$-glycosidic linkages in cellulose.

Question 1

Which functional group is primarily responsible for the acidic properties of amino acids and is involved in peptide bond formation?

Accepted Answer

Carboxyl group ($-COOH$)

Question 2

A molecule contains a carbon atom double-bonded to an oxygen atom at the end of its carbon skeleton. What type of functional group does this represent, and what is the molecule classified as?

Accepted Answer

Carbonyl group; aldehyde

Question 3

Which process is responsible for joining monomers together to form polymers, and what is the byproduct of this reaction?

Accepted Answer

Dehydration synthesis; water is produced

Question 4

Cellulose is a polysaccharide that cannot be digested by most animals. What is the main reason for this?

Accepted Answer

Animals lack the enzyme to break the $eta$-glycosidic linkages in cellulose.

Question 5

Which of the following best describes the structure and function of phospholipids in biological membranes?

Accepted Answer

They consist of a glycerol backbone, two fatty acids, and a phosphate group, forming a bilayer due to their amphipathic nature.

Question 6

A protein loses its three-dimensional structure when exposed to high temperature. What is this process called, and which levels of protein structure are most affected?

Accepted Answer

Denaturation; secondary, tertiary, and quaternary structures

Question 7

Which of the following is a correct match between a disaccharide and its monomer components?

Accepted Answer

Sucrose: Glucose + Fructose

Question 8

Which functional group is critical for stabilizing protein structure through the formation of disulfide bridges?

Accepted Answer

Sulfhydryl group ($-SH$)

Question 9

Which class of macromolecules is primarily responsible for catalyzing biochemical reactions in cells?

Accepted Answer

Proteins

Question 10

A triglyceride is formed by the reaction of which molecules, and what type of bond is created?

Accepted Answer

Three fatty acids and one glycerol; ester bonds

Question 11

Which of the following statements about the primary structure of a protein is correct?

Accepted Answer

It is determined by the sequence of amino acids encoded by genes.

Question 12

Which macromolecule contains genetic information and is composed of nucleotide monomers?

Accepted Answer

Nucleic acids

Question 13

Which of the following is a storage polysaccharide found in animals, and where is it primarily stored?

Accepted Answer

Glycogen; liver and muscle cells

Question 14

Which functional group acts as a weak base and is commonly found in amino acids?

Accepted Answer

Amino group ($-NH_2$)

Question 15

Which of the following best explains why saturated fatty acids are solid at room temperature while unsaturated fatty acids are liquid?

Accepted Answer

Saturated fatty acids have straight chains that pack tightly, while unsaturated fatty acids have kinks due to double bonds that prevent tight packing.

Question 16

Which process breaks the covalent bond between two monomers by the addition of water?

Accepted Answer

Hydrolysis

Question 17

Which of the following is NOT a function of proteins in living organisms?

Accepted Answer

Energy storage

Question 18

Which level of protein structure is primarily stabilized by hydrogen bonds between peptide linkages in the backbone?

Accepted Answer

Secondary structure

Question 19

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

Accepted Answer

Chitin

Question 20

A scientist is studying a molecule with the formula $C_6H_{12}O_6$. Which class of biological molecule does this most likely represent, and what is its primary function?

Accepted Answer

Monosaccharide; energy source

Biological Molecules: Structure, Function, and Classification

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