Chapter 2 Practice Test
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. The three particles that make up atoms are
a. protons, neutrons, and isotopes.
b. neutrons, isotopes, and electrons.
c. positives, negatives, and neutrals.
d. protons, neutrons, and electrons.
____
2. What are found in the space surrounding the nucleus of an atom?
a. protons
b. electrons
c. neutrons
d. ions
____
3. Subatomic particles are
a. particles that are smaller than an atom.
b. made up of a single atom.
c. particles found beneath atoms.
d. composed of several atoms.
____
4. If an atom contains 3 protons, 4 neutrons, and 3 electrons, its mass number is
a. 3.
b. 4.
c. 7.
d. 11.
____
5. A chlorine atom that has 17 protons and 18 neutrons is called
a. chlorine-17.
b. chlorine-18.
c. chlorine-35.
d. chlorine-1.
____
6. Isotopes are atoms of the same element with the same number of protons and a different number of
a. electrons.
b. molecules.
c. neutrons.
d. ions.
____
7. If an atom contains 11 protons and 12 neutrons, its atomic number is
a. 1.
b. 11.
c. 12.
d. 23.
____
8. Which of the following is a substance formed by the chemical joining of two or more elements in definite
amounts?
a. compound
b. isotope
c. nucleus
d. enzyme
____
9. Which of the following makes up a molecule of water?
a. one atom of hydrogen and one atom of oxygen
b. one atom of sodium and one atom of chlorine
c. one atom of hydrogen and two atoms of oxygen
d. two atoms of hydrogen and one atom of oxygen
____ 10. Which of the following statements about a compound is true?
a. The physical and chemical properties of a compound are usually very different from those
of the elements from which it is formed.
b. Only the physical properties of a compound are usually the same as those of the elements
from which it is formed.
c. Only the chemical properties of a compound are usually the same as those of the elements
from which it is formed.
d. The physical and chemical properties of a compound are usually the same as those of the
elements from which it is formed.
____ 11. A covalent bond is formed as the result of
a. transferring electrons.
b. sharing electrons.
c. transferring protons.
d. sharing protons.
____ 12. Which term does NOT apply to sodium chloride?
a. molecule
b. ionic bonding
c. compound
d. crystal
____ 13. What type of electron is available to form bonds?
a. valence
b. nucleus
c. ionic
d. covalent
____ 14. What type of ion forms when an atom loses electrons?
a. neutral
b. positive
c. negative
d. radioactive
Figure 2–1
____ 15. Which property of water causes the curved surface shown in Figure 2–1?
a.
b.
c.
d.
pH
cohesion
adhesion
heat capacity
____ 16. Water molecules are polar, with the
a. oxygen side being slightly positive and the hydrogen side being slightly negative.
b. oxygen and hydrogen sides being slightly positive.
c. oxygen and hydrogen sides being slightly negative.
d. oxygen side being slightly negative and the hydrogen side being slightly positive.
____ 17. In a water molecule, shared electrons spend more time around the oxygen atom than the hydrogen atoms. As
a result, the oxygen atom is
a. slightly negative.
b. very negative.
c. slightly positive.
d. very positive.
____ 18. A solution is a
a. combination of isotopes.
b. chemical reaction.
c. mixture in which the substances are evenly spread out.
d. mixture in which undissolved substances do not settle out.
____ 19. If you stir salt into boiling water, you produce a
a. mixture called a suspension.
b. mixture called a solution.
c. solution and suspension.
d. mixture only.
____ 20. When salt is dissolved in water, water is the
a. reactant.
b. solution.
c. solute.
d. solvent.
____ 21. Which of the following is NOT a monomer?
a. a glucose molecule
b. an amino acid
c. a nucleotide
d. a protein
____ 22. Which statement is true about macromolecules?
a. Simple sugars are made of polysaccharides.
b. Glycerol is made of fatty acids.
c. Proteins are made of amino acids.
d. Nucleotides are made of nucleic acids.
____ 23. Chemical reactions that release energy
a. will not occur.
b. need catalysts to occur.
c. will always explode.
d. often occur spontaneously.
____ 24. If a reaction in one direction releases energy, the reaction in the opposite direction
a. also releases energy.
b. absorbs energy.
c. destroys energy.
d. cannot occur.
____ 25. Which of the following diagrams correctly shows the reaction pathway of a reaction that absorbs energy?
a.
b.
c.
d.
____ 26. Which of the following statements about enzymes is NOT true?
a. Enzymes work best at a specified pH.
b. All enzymes have the same shape as their substrates.
c. Enzymes are proteins.
d. The shape of an enzyme allows it to do its job.
____ 27. Which of the following statements is true about catalysts?
a. Catalysts slow down the rate of chemical reactions.
b. All catalysts are enzymes.
c. Catalysts are used up during a chemical reaction.
d. Catalysts lower the activation energy of a chemical reaction.
____ 28. Amino acid is to protein as
a. fat is to lipid.
b. DNA is to RNA.
c. sugar is to fat.
d. simple sugar is to starch.
____ 29. Which of the following is NOT a function of proteins?
a. store and transmit genetic information
b. help to fight disease
c. control the rate of reactions
d. move substances into or out of cells
____ 30. The energy needed to get a reaction started is the
a. adhesion energy.
b. activation energy.
c. cohesion energy.
d. chemical energy.
____ 31. A substance that speeds up the rate of a chemical reaction is called
a. a catalyst.
b. a lipid.
c. a molecule.
d. an element.
____ 32. Enzymes affect the reactions in living cells by changing the
a. products of the reaction.
b. speed of the reaction.
c. temperature of the reaction.
d. pH of the reaction.
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____
1. Lipids are important parts of biological membranes and waterproof coverings. _________________________
____
2. The chemical reaction of
____
3. Proteins that speed up the rate of reactions in living things are substrates. _________________________
and
is irreversible. _________________________
Completion
Complete each statement.
1. Complex carbohydrates are to monosaccharides as polymers are to ____________________.
2. Chemical reactions that ____________________ energy will not occur without a source of energy.
3. The energy need to start a chemical reaction is called the ____________________.
4. The name of an enzyme usually ends in ____________________.
Short Answer
1. What is the difference between a saturated fatty acid and an unsaturated fatty acid?
Figure 2–3
2. In Figure 2–3, the pieces labeled A and T are nitrogenous bases. What kind of macromolecule is shown?
Label the other parts of the molecule.
3. Where does the energy that enables you to breathe and think come from?
4. Name two essential roles that enzymes play in cells.
Science Skills
Figure 2–6
1. Interpret Graphs Based on Figure 2–6, which enzyme is active over the largest temperature range?
2. Apply Concepts According to Figure 2–6, which enzyme would you expect to find in a bacterium growing in
a hot spring?
3. Interpret Graphs According to Figure 2–6, at what temperature do the two enzymes have the same amount
of activity?
4. Interpret Graphs According to Figure 2–6, what are the optimum temperatures for each enzyme?
5. Apply Concepts Based on Figure 2–6, which enzyme would have the most activity in humans?
Essay
1. The four groups of macromolecules are carbohydrates, lipids, nucleic acids, and proteins. Which of these
groups are polymers and which are not? Explain your answer.
Figure 2–7
2. The graphs in Figure 2–7 show the same reaction: X + Y  XY, where X reacts with Y, producing XY.
Explain why the two graphs differ. Which graph shows a reaction that is easier to start? Explain your answer.
3. How is energy related to the reactants and products of a chemical reaction?