Chapter 2 Practice Test

Something with a pH of 5 would __________.

have more H+ ions than OH- ions

Which of the following is the primary energy-transferring molecule in cells?

ATP: main energy currency of a cell

Which of the following is NOT a way to distinguish an acid from a base?

An acidic substance will have a sticky feel.

Which of the following is a property of matter?

Matter can exist in solid, liquid, or gaseous state.

Which of the following is NOT one of the four basic elements that compose approximately 96% of a human's body weight?

Potassium

Which of the following best defines potential energy?

Potential energy is stored energy that has the capacity to do work but is not presently doing so

The atomic number of any atom is equal to the number of protons in its nucleus.

True

The major function of RNA is to carry out the genetic instructions for protein synthesis.

True

Which of the following is true of atoms?

Atoms of any given element will differ from those of all other elements and provide its unique physical and chemical properties.

Which of the following is FALSE regarding DNA?

DNA carries out the orders for protein synthesis issued by RNA.

Electrons bear a positive charge equal in strength to the negative charge of the proton.

False

Polar molecules are electrically balanced as a result of the equal sharing of electrons between the atoms of the molecules.

False

Which of the following is true of an isotope?

Isotopes have the same number of protons but differ in the number of neutrons they contain.

Match the following organic molecules to their biochemical building blocks, or monomers.

Triglycerides- glycerol and fatty acids Carbohydrates- monosaccharides Proteins-amino acids DNA- nucleotides

All organic molecules contain carbon.

True

Colloids (emulsions) are heterogeneous mixtures.

True

Enzymes are unchanged in a reaction; they can be reused, and are NOT needed in large quantities.

True: Three basic steps appear to be involved in enzyme action: The enzyme's active site binds to the substrate(s) on which it acts, temporarily forming an enzyme-substrate complex. The enzyme-substrate complex undergoes internal rearrangements that form the product(s). The enzyme releases the product(s) of the reaction. Because enzymes are unchanged by their catalytic role and can act again and again, cells need only small amounts of each enzyme.

Which of the following does NOT represent an accurate hierarchy in the natural combination of matter?

When two or more similar kinds of atoms bind, they form an isotope.

If the pH or temperature of the environment that contains a protein is altered dramatically, then the protein may __________.

become denatured

Buffers____________

stabilize pH

Which of the following types of chemical reactions always involves atoms or molecules combining to form a larger, more complex molecule?

synthesis: When atoms or molecules combine to form a larger, more complex molecule, the process is a synthesis, or combination, reaction.

In an ionic bond, __________.

there is a transfer of one or more electrons from one atom to the other

In biochemistry, and thus in the body, the universal solvent is __________.

water