Question 1

Which of the following statements best explains why starch and glycogen are suitable for energy storage in cells, while glucose is not stored in its monomeric form?

Accepted Answer

Starch and glycogen are large, insoluble polymers that do not exert osmotic pressure, while glucose is small and soluble, which would disrupt cell osmotic balance.

Question 2

Which type of glycosidic bond is found at the branch points of amylopectin and glycogen?

Accepted Answer

$$\alpha-1$$,6-glycosidic bond

Question 3

A solution of an unknown sugar is tested with Benedict’s reagent and produces a brick-red precipitate. Which conclusion is most accurate?

Accepted Answer

The sugar contains a free aldehyde or ketone group and is a reducing sugar.

Question 4

Which structural feature distinguishes $$\alpha-$$glucose from $$\beta-$$glucose?

Accepted Answer

The position of the hydroxyl group on carbon 1: below the ring in $$\alpha-$$glucose and above the ring in $$\beta-$$glucose.

Question 5

Which of the following best explains why cellulose provides high tensile strength to plant cell walls?

Accepted Answer

Cellulose chains are unbranched, composed of $$\beta-$$glucose, and form microfibrils through extensive hydrogen bonding between parallel chains.

Question 6

Which of the following is a correct description of the reaction that forms a peptide bond?

Accepted Answer

A condensation reaction between the amino group of one amino acid and the carboxyl group of another, releasing water.

Question 7

Which property of triglycerides makes them an efficient energy storage molecule in animals?

Accepted Answer

They have a high proportion of C-H bonds, yielding more ATP per gram than carbohydrates when oxidized.

Question 8

Which of the following best describes the amphipathic nature of phospholipids and its biological significance?

Accepted Answer

Phospholipids have both hydrophilic phosphate heads and hydrophobic fatty acid tails, allowing them to form bilayers that are the basis of cell membranes.

Question 9

A patient is found to have a genetic mutation that replaces glycine with a bulky amino acid in the collagen triple helix. What is the most likely consequence?

Accepted Answer

The triple helix will be destabilized, reducing collagen’s tensile strength.

Question 10

Which of the following bonds is NOT involved in stabilizing the tertiary structure of a protein?

Accepted Answer

Phosphodiester bonds

Question 11

Which of the following best explains why a drastic change in pH can denature a protein?

Accepted Answer

It disrupts ionic and hydrogen bonds between R groups, altering the tertiary and quaternary structure.

Question 12

Which of the following statements about the Biuret test for proteins is correct?

Accepted Answer

It detects the presence of peptide bonds by forming a purple complex with $$\mathrm{Cu$$^{2+}$$}$$ ions under alkaline conditions.

Question 13

Which of the following best describes the role of chaperone proteins in cells?

Accepted Answer

They assist in the proper folding and refolding of polypeptides, preventing aggregation and misfolding.

Question 14

Which of the following is a correct comparison between amylose and cellulose?

Accepted Answer

Amylose is composed of $$\alpha-$$glucose with $$\alpha-1$$,4-glycosidic bonds and is helical, while cellulose is composed of $$\beta-$$glucose with $$\beta-1$$,4-glycosidic bonds and is straight-chained.

Question 15

Which of the following best explains why unsaturated fatty acids tend to be liquid at room temperature?

Accepted Answer

The presence of double bonds introduces kinks, preventing tight packing of molecules.

Question 16

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

Accepted Answer

It is a globular protein with four polypeptide subunits, each containing a haem group that binds oxygen.

Question 17

Which of the following best describes the effect of heavy metal ions on protein structure?

Accepted Answer

They form strong bonds with negatively charged R-groups, disrupting ionic bonds and reducing protein solubility.

Question 18

Which of the following is a correct description of the molecular structure of a phospholipid?

Accepted Answer

One glycerol, two fatty acids, and one phosphate group, with the phosphate group forming the hydrophilic head.

Question 19

Which of the following best explains why the sequence of amino acids in a protein determines its final three-dimensional structure?

Accepted Answer

The sequence of amino acids determines the chemical properties and interactions of R groups, which drive folding into the correct structure.

Biomolecules: Structure and Function of Carbohydrates and Lipids

Study Guide - Practice Questions

Study Guide - Flashcards