Q: A patient is unable to digest cellulose but can digest starch. Which structural difference between these two polysaccharides explains this phenomenon?

Cellulose contains $$eta-1$$,4-glycosidic linkages, while starch contains $$oldsymbol{\alpha}-1$$,4-glycosidic linkages.

Question 1

Which of the following best describes the difference between dehydration (condensation) and hydrolysis reactions in the context of biological macromolecules?

Accepted Answer

Dehydration reactions join monomers by removing a water molecule, while hydrolysis reactions break polymers into monomers by adding a water molecule.

Question 2

A patient is unable to digest cellulose but can digest starch. Which structural difference between these two polysaccharides explains this phenomenon?

Accepted Answer

Cellulose contains $$eta-1$$,4-glycosidic linkages, while starch contains $$oldsymbol{\alpha}-1$$,4-glycosidic linkages.

Question 3

Which of the following statements about phospholipids is correct?

Accepted Answer

Phospholipids have two fatty acids and a phosphate group attached to glycerol, resulting in both hydrophobic and hydrophilic regions.

Question 4

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

Accepted Answer

Unsaturated fatty acids have double bonds that create kinks, preventing tight packing of molecules.

Question 5

A mutation causes a single amino acid substitution in the primary structure of a protein. Which level(s) of protein structure could be affected as a result?

Accepted Answer

All levels—primary, secondary, tertiary, and quaternary—could be affected.

Question 6

Which of the following best describes the orientation of the two strands in a DNA double helix?

Accepted Answer

The two strands run antiparallel: one 5$$' to 3$'$$, the other 3$$' to 5$'.$$

Question 7

Which of the following is a correct pairing of a macromolecule with its monomer?

Accepted Answer

Carbohydrate – Monosaccharide

Question 8

Which of the following bonds is responsible for stabilizing the secondary structure of proteins?

Accepted Answer

Hydrogen bonds between backbone atoms

Question 9

A researcher isolates a polysaccharide from a plant cell wall. Which of the following is most likely the identity of this molecule, and what is its main function?

Accepted Answer

Cellulose; structural support

Question 10

Which of the following statements about the formation of a peptide bond is correct?

Accepted Answer

A peptide bond forms via a dehydration reaction between the amino group of one amino acid and the carboxyl group of another.

Question 11

Which of the following best explains why humans can digest starch but not cellulose?

Accepted Answer

Humans have enzymes that hydrolyze $$\alpha-$$glycosidic linkages in starch but lack enzymes to hydrolyze $$\beta-$$glycosidic linkages in cellulose.

Question 12

Which of the following is a function of cholesterol in animal cells?

Accepted Answer

It is a precursor for steroid hormones and helps maintain membrane fluidity.

Question 13

Which of the following best describes the structure of a nucleotide?

Accepted Answer

A phosphate group, a pentose sugar, and a nitrogenous base

Question 14

A scientist is studying a protein that loses its function when exposed to high temperatures. Which level(s) of protein structure are most likely disrupted?

Accepted Answer

Secondary, tertiary, and quaternary structures

Question 15

Which of the following statements about the flow of genetic information is correct?

Accepted Answer

DNA is transcribed into RNA, which is translated into protein.

Question 16

Which of the following best explains why chitin is a strong and flexible material found in arthropod exoskeletons?

Accepted Answer

Chitin is a polymer of glucose with a nitrogen-containing appendage, forming strong hydrogen bonds between chains.

Question 17

Which of the following is true regarding the difference between RNA and DNA nucleotides?

Accepted Answer

RNA nucleotides contain ribose, while DNA nucleotides contain deoxyribose.

Question 18

A sample of an unknown macromolecule is found to contain the elements C, H, O, N, and P. Which class of biological macromolecule is most likely present?

Accepted Answer

Nucleic acid

Question 19

Which of the following best describes the role of glycosidic linkages in polysaccharides?

Accepted Answer

They join monosaccharides together to form polysaccharides, and their type determines structure and digestibility.

Biological Macromolecules: Structure, Function, and Synthesis

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