Chapter Test: The Chemistry of Life

The results of the experiment are MOST USEFUL for explaining which of these functions of lipids in organisms?

• forming a waterproof covering on feathers, leaves, and fruits.

• providing energy for the cell

• allowing water to pass through the cell membrane

• replacing water in dry environments

What event changes an atom into an ion?

• the sharing of electrons with another atom

• the gain or loss of one or more electrons

• the gain or loss of one or more neutrons

• a chemical reaction that forms a molecule

How does carbonic anhydrase change the reaction between carbon dioxide and water?

• It increases the total energy released.

• It alters the structure of the product.

• It decreases the activation energy.

• It decreases the total mass of the system.

Household bleach has a pH between 12 and 13. From this information, which of the following BEST describes the bleach solution?

• The solution is acidic, meaning it has more hydrogen (H⁺) ions than hydroxide (OH⁻) ions.

• The solution is basic, meaning it has fewer hydrogen (H⁺) ions than hydroxide (OH⁻) ions.

• The solution is neutral, meaning it has an equal number of hydrogen (H⁺) ions and hydroxide (OH⁻) ions.

• The solution is a buffer that reacts with solutions containing high concentrations of hydrogen (H⁺) ions.

After the enzyme releases a molecule of carbonic acid, what MOST LIKELY will occur next?

• The enzyme will be degraded, or broken apart.

• The enzyme will repeat its function of binding reactants and releasing carbonic acid.

• The enzyme will take on a new function and catalyze a different chemical reaction.

• The enzyme will take on a new function that does not involve chemical reactions, such as providing cell structure or support.

A team of scientists and engineers is working together to develop a new cleaning product. The team has identified a species of bacteria that gets energy by breaking apart lipids and oils. The team wants to isolate the key substance that the bacteria use for this process, and then adapt the substance for the new cleaning product. Which macromolecule should the team try to isolate from the bacteria?

• a lipid or oil that is unique to the bacteria

• a protein that specifically binds lipids or oils

• a carbohydrate that is about the same size as a typical lipid or oil molecule

• a nucleic acid that codes for the production of a lipid or oil

What allows the three atoms in a water molecule to stay together?

• covalent bonds formed by shared electrons between atoms

• covalent bonds formed by electrons that transfer between atoms

How do any two types of amino acids differ from one another?

• the number of amino groups in the molecule

• the number of carboxyl groups in the molecule

• the chemical structure of the R group in the molecule

• the number of chemical bonds formed by the central carbon atom

Which type of macromolecule has the function of storing and transmitting hereditary or genetic information?

• lipid

• carbohydrate

• nucleic acid

• protein

The diagram shows water at the molecular level. What property of a water molecule allows hydrogen bonds to form among adjacent molecules?

• the strong covalent bonds that hold the oxygen atom to each hydrogen atom

• the ionic bonds that form after the molecule separates into a hydroxide ion (OH⁻) and hydrogen ion (H⁺)

• the small size of the two hydrogen atoms compared to the oxygen atom

• the polarity of the molecule, which involves a slightly negative oxygen atom and slightly positive hydrogen atoms