Question 1

Which property of water is primarily responsible for the ability of some insects to walk on the surface of a pond without sinking?

Accepted Answer

Surface tension resulting from hydrogen bonding

Question 2

A scientist is studying a molecule that contains only carbon, hydrogen, and oxygen, with a hydrogen to oxygen ratio of approximately 2:1. This molecule is most likely a:

Accepted Answer

Carbohydrate

Question 3

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

Accepted Answer

Water's polarity allows it to form hydrogen bonds with polar and ionic substances.

Question 4

During dehydration synthesis, which of the following occurs?

Accepted Answer

Two monomers are joined together and a water molecule is released.

Question 5

Which of the following statements about saturated fatty acids is correct?

Accepted Answer

They contain only single bonds between carbon atoms.

Question 6

A patient is suffering from a genetic disorder that affects the tertiary structure of a protein. Which of the following interactions is most likely disrupted?

Accepted Answer

Hydrophobic interactions among R groups

Question 7

Which element is NOT one of the four most prevalent elements used to build biological molecules?

Accepted Answer

Phosphorus

Question 8

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

Accepted Answer

DNA contains the sugar deoxyribose, while RNA contains ribose.

Question 9

A biologist adds a drop of oil to a beaker of water. The oil does not dissolve and forms a separate layer. Which property of lipids does this demonstrate?

Accepted Answer

Lipids are hydrophobic and do not mix with water.

Question 10

Which of the following best explains why water has a high specific heat capacity?

Accepted Answer

Hydrogen bonds between water molecules absorb heat energy.

Question 11

A DNA double helix is described as 'antiparallel.' What does this mean?

Accepted Answer

The two strands run in opposite directions: one 5' to 3', the other 3' to 5'.

Question 12

Which of the following is a function of phospholipids in living organisms?

Accepted Answer

They form the main structural component of cell membranes.

Question 13

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

Accepted Answer

The sequence of amino acids in the polypeptide chain

Question 14

Which of the following statements about hydrolysis is correct?

Accepted Answer

Hydrolysis breaks a covalent bond by adding a water molecule.

Question 15

A mutation changes a single amino acid in the active site of an enzyme. Which level of protein structure is directly affected?

Accepted Answer

Primary structure

Question 16

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds in ice create a lattice that is less dense than liquid water.

Question 17

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

Accepted Answer

Carbohydrate – monosaccharide

Question 18

A researcher is studying the effect of temperature on enzyme activity. She finds that increasing the temperature beyond a certain point causes the enzyme to lose its function. Which structural level of the enzyme is most likely disrupted?

Accepted Answer

Secondary and tertiary structures

Question 19

Which of the following best describes the role of carbon in biological macromolecules?

Accepted Answer

Carbon forms the backbone of carbohydrates, proteins, lipids, and nucleic acids.

Question 20

Which of the following equations correctly represents the hydrolysis of a disaccharide into two monosaccharides?

Accepted Answer

$$C_{12}H$$_{22}$$O_{11} + H$$_{2}$$O \rightarrow 2C_{6}H$$_{12}$$O_{6}$

Chemistry of Life: Structure and Function of Biological Molecules

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