Name: Date: Hour:
Study Guide Chapter 2.3 & 2.4
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____1.Why is carbon so special compared to other elements?
a. / Carbon atoms can bond to one another and form a lot of different structures.b. / Carbon atoms have four valence electrons and can form quadruple bonds.
c. / Only carbon atoms can form covalent bonds with oxygen and hydrogen.
d. / Only carbon atoms can be dissolved in water solutions and suspensions.
Figure 2–2
____2.What kinds of atoms are bonded to carbon atoms in the molecule shown in Figure 2–2?
a. / helium, oxygen, and nitrogenb. / calcium, hydrogen, and oxygen
c. / hydrogen, oxygen, and nitrogen
d. / helium, carbon, and sodium
____3.Carbon-12 is the most common isotope of carbon. It has 6 protons, 6 neutrons, and 6 electrons. Of its 6 electrons, 4 are valence electrons. How many covalent bonds can a carbon atom form?
a. / 1b. / 4
c. / 6
d. / 12
____4.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.
____5.Which of the following is NOT a monomer?
a. / a glucose moleculeb. / an amino acid
c. / a nucleotide
d. / a protein
____6.Which of the following is NOT a function of proteins?
a. / store and transmit genetic informationb. / help to fight disease
c. / control the rate of reactions
d. / move substances into or out of cells
____7.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.
____8.In chemical reactions, atoms are
a. / created.b. / destroyed.
c. / rearranged.
d. / neutralized.
____9.When hydrogen and oxygen combine to form water, water is
a. / a product.b. / a reactant.
c. / an enzyme.
d. / a catalyst.
____10.Identify the reactant(s) in the chemical reaction, CO2 + H2O H2CO3.
a. / CO2, H2O, and H2CO3b. / CO2 and H2O
c. / H2CO3
d. / CO2
____11.What is the process that changes one set of chemicals into another set of chemicals?
a. / Cohesionb. / hydrogen bonding
c. / chemical reaction
d. / Dissolving
____12.The energy needed to get a reaction started is the
a. / adhesion energy.b. / activation energy.
c. / cohesion energy.
d. / chemical energy.
____13.Chemical reactions that release energy
a. / will not occur.b. / need catalysts to occur.
c. / will always explode.
d. / often occur spontaneously.
____14.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.
____15.Which of the following diagrams correctly shows the reaction pathway of a reaction that absorbs energy?
a. /b. /
c. /
d. /
____16.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.
____17.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.
____18.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.
____19.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.
____20.The molecules of life are all carbon-based. ______
____21.Carbon-carbon bonds can be single, double, or triple ionic bonds. ______
____22.Lipids are important parts of biological membranes and waterproof coverings. ______
____23.The substances that are present when a chemical reaction begins are the products. ______
____24.The chemical reaction of and is irreversible. ______
____25.Proteins that speed up the rate of reactions in living things are substrates. ______
Completion
Complete each statement.
26.Because carbon atoms can bond to one another, they can form long ______that can be almost unlimited in length.
27.Complex carbohydrates are to monosaccharides as polymers are to ______.
28.The elements or compounds that come out of a chemical reaction are ______.
29.Chemical reactions that ______energy will not occur without a source of energy.
30.The energy need to start a chemical reaction is called the ______.
31.The name of an enzyme usually ends in ______.
Name: Date: Hour:
Study Guide Chapter 2.3 & 2.4
Answer Section
MULTIPLE CHOICE
1.ANS:A
2.ANS:C
3.ANS:B
4.ANS:D
5.ANS:D
6.ANS:A
7.ANS:C
8.ANS:C
9.ANS:A
10.ANS:B
11.ANS:C
12.ANS:B
13.ANS:D
14.ANS:B
15.ANS:D
16.ANS:B
17.ANS:D
18.ANS:A
19.ANS:B
MODIFIED TRUE/FALSE
20.ANS:T
21.ANS:F, covalent
22.ANS:T
23.ANS:F, reactants
24.ANS:F, reversible
25.ANS:F, enzymes
COMPLETION
26.ANS:chains
27.ANS:monomers
28.ANS:products
29.ANS:absorb
30.ANS:activation energy
31.ANS:-ase