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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 nitrogen
b. / 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. / 1
b. / 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 molecule
b. / 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 information
b. / 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 H2CO3
b. / CO2 and H2O
c. / H2CO3
d. / CO2

____11.What is the process that changes one set of chemicals into another set of chemicals?

a. / Cohesion
b. / 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 ______.

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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