Question 1

Which of the following best describes the relationship between hydrolysis and condensation reactions in biological systems?

Accepted Answer

Condensation forms polymers by removing water, while hydrolysis breaks polymers by adding water.

Question 2

Which of the following is a correct example of a glycosidic linkage in a disaccharide?

Accepted Answer

A covalent bond between two monosaccharides formed by removing a water molecule

Question 3

A scientist discovers a molecule with the formula $\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$. Which class of biomolecule does this most likely represent, and what is its primary function?

Accepted Answer

Carbohydrate; short-term energy storage

Question 4

Which of the following statements about triglycerides is correct?

Accepted Answer

They are formed by condensation reactions between fatty acids and glycerol, creating ester linkages.

Question 5

Amino acids with side chains containing only hydrocarbons are classified as:

Accepted Answer

Hydrophobic

Question 6

Which level of protein structure is directly determined by the sequence of amino acids in a polypeptide?

Accepted Answer

Primary structure

Question 7

Which of the following best explains why cellulose cannot be digested by most animals?

Accepted Answer

Most animals lack the enzymes to break the $\beta$-1,4 glycosidic linkages in cellulose.

Question 8

Which of the following correctly matches a polymer with its monomer and the type of bond that links them?

Accepted Answer

Nucleic acid – nucleotide – phosphodiester bond

Question 9

A DNA strand has a 5' end and a 3' end. What does 'antiparallel' mean in the context of DNA structure?

Accepted Answer

One strand runs 5' to 3', and the other runs 3' to 5'.

Question 10

Which of the following molecules is correctly matched with its primary cellular role?

Accepted Answer

cAMP – secondary messenger in signal transduction

Question 11

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds; unsaturated fatty acids contain one or more double bonds.

Question 12

A mutation causes a single amino acid change in the primary structure of a protein. Which levels of protein structure could potentially be affected?

Accepted Answer

Primary, secondary, tertiary, and quaternary structures

Question 13

Which of the following is a function of phospholipids in biological membranes?

Accepted Answer

Forming a bilayer that separates the cell from its environment

Question 14

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

ATP contains high-energy phosphate bonds that can be hydrolyzed to release energy for cellular work.

Question 15

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes are proteins that lower the activation energy of chemical reactions.

Question 16

A researcher is analyzing an unknown amino acid. Its side chain contains a carboxyl group and is negatively charged at physiological pH. How should this amino acid be classified?

Accepted Answer

Hydrophilic and charged (acidic)

Question 17

Which of the following is a correct description of a phosphodiester bond?

Accepted Answer

A bond between the phosphate group of one nucleotide and the sugar of another nucleotide in nucleic acids

Question 18

Which of the following best describes the quaternary structure of a protein?

Accepted Answer

The arrangement and interaction of multiple polypeptide subunits in a protein

Question 19

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

Accepted Answer

Catalyzing chemical reactions

Question 20

Which of the following best explains why phospholipids are described as amphipathic molecules?

Accepted Answer

They contain both hydrophobic fatty acid tails and a hydrophilic phosphate head.

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