Chapter 2 Chemistry of Life

Ice floats on water because

• of cohesion.
• ice has a higher density than water.
• water shrinks when it freezes.
• water expands when it freezes.

Water molecules are polar, with the

• oxygen side being slightly positive and the hydrogen side being slightly negative.
• oxygen and hydrogen sides being slightly positive.
• oxygen and hydrogen sides being slightly negative.
• oxygen side being slightly negative and the hydrogen side being slightly positive.

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When salt is dissolved in water, water is the

• reactant.
• solution.
• solute.
• solvent.

A substance with a pH of 6 is called

• an acid.
• a base.
• both an acid and a base.
• neither an acid nor a base.

Solutions that contain concentrations of H⁺ ions lower than pure water

• have pH values below 7.
• are acids.
• are bases.
• are enzymes.

A monosaccharide is a

• carbohydrate.
• lipid.
• nucleic acid.
• protein.

Fats, oils, and cholesterol are all types of

• cell membranes.
• hormones.
• lipids.
• fatty acids.

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Use the graph

• The reaction with the enzyme occurs at a slower rate.
• More energy is released by the original reaction.
• The original reaction is catalyzed.
• Less energy is needed to start the reaction with the enzyme.

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Atoms connected by covalent bonds share

• pairs of electrons.
• hydrogen ions.
• ionic compounds.
• carbon and oxygen.

An ion is formed when an atom gains or loses

• electrons.
• protons.
• bonds.
• neutrons.

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