Question 1

Which property of water is primarily responsible for the ability of some insects to walk on its surface?

Accepted Answer

Cohesion due to hydrogen bonding

Question 2

A scientist is comparing the energy required to break a C=O double bond in carbon dioxide ($CO_2$) and a Si–O single bond in silicon dioxide ($SiO_2$). Which statement is correct based on bond energies?

Accepted Answer

Breaking a C=O bond requires more energy than breaking a Si–O bond.

Question 3

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

Accepted Answer

Saturated fatty acids contain only single bonds between carbon atoms, while unsaturated fatty acids contain one or more double bonds.

Question 4

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

Accepted Answer

Primary structure

Question 5

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

Accepted Answer

Primary, secondary, and tertiary structures

Question 6

Which of the following is a correct pairing of a carbohydrate type with an example?

Accepted Answer

Disaccharide – Maltose

Question 7

Which of the following statements about phospholipids is correct?

Accepted Answer

They form the main structure of cell membranes due to their amphipathic nature.

Question 8

Which of the following best explains why water is an excellent solvent for many biological molecules?

Accepted Answer

Water is polar, allowing it to interact with and dissolve other polar and ionic substances.

Question 9

Which of the following is a function of RNA that distinguishes it from DNA?

Accepted Answer

RNA can act as a catalyst (ribozyme) in some biological reactions.

Question 10

A student is given a sample of an unknown biological molecule. It is found to contain a phosphate group, a pentose sugar, and a nitrogenous base. Which class of biological molecule is this?

Accepted Answer

Nucleic acid

Question 11

Which of the following best describes the process of hydrolysis?

Accepted Answer

The breakdown of a polymer into monomers by the addition of a water molecule

Question 12

Which of the following is a correct statement about ATP?

Accepted Answer

ATP contains three phosphate groups and is the primary energy currency of the cell.

Question 13

Which of the following best explains why cellulose is not digestible by humans, while starch is?

Accepted Answer

Humans lack the enzyme to break the specific glycosidic bonds in cellulose.

Question 14

Which of the following is a correct description of the quaternary structure of a protein?

Accepted Answer

The association of multiple polypeptide chains into a functional protein complex

Question 15

Which of the following best describes the difference between DNA and RNA?

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 16

A patient is diagnosed with a genetic disorder that affects the structure of their hemoglobin protein. Which level(s) of protein structure could be altered to cause this disorder?

Accepted Answer

Any or all levels: primary, secondary, tertiary, or quaternary

Question 17

Which of the following is a real-life example of the importance of enzyme specificity?

Accepted Answer

Lactase only catalyzes the hydrolysis of lactose, not sucrose, which is why some people are lactose intolerant.

Question 18

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

Their hydrophobic tails avoid water while their hydrophilic heads interact with water, leading to bilayer formation.

Question 19

Which of the following is a correct statement about the role of carbohydrates in living organisms?

Accepted Answer

Carbohydrates serve as both energy sources and structural components in cells.

Question 20

A researcher is studying a molecule with the following structure: a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable R group. What type of molecule is this?

Accepted Answer

An amino acid

Biological Molecules: Structure, Function, and Diversity

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