Using Key Terms
1.Atoms share electrons in a(n) _____ bond.
a.covalent c.ionic
b.hydrogen d.nuclear
2.A weak attraction between polar molecules
is called a(n) _____ bond.
a.compound c.ionic
b.covalent d.hydrogen
3.A substance that forms hydrogen ions
when dissolved in water is called a(n)
a.atom. c.base.
b.acid. d.carbohydrate.
4.The energy needed to start a chemical
reaction is called _____ energy.
a.cohesive c.activation
b.adhesive d.ionic
5.Write a sentence that shows your under-
standing of each of the following terms:
carbohydrate, lipid, nucleic acid, and protein.Understanding Key Ideas
6.Most atoms contain one or more
a.neutrons. c.protons.
b.electrons. d.All of the above
7.Water dissolves ionic compounds because
water molecules
a.are nonpolar.
b.have a pH value of 14 or greater.
c.have partially charged ends.
d.do not contain atoms.
8.In cells, ATP temporarily stores
a.amino acids. c.energy.
b.DNA. d.lipids.
9.Energy needed for metabolism does not
come from
a.food.
b.lipids.
c.carbohydrates.
d.water.10.Most enzymes are
a.lipids.
b.carbohydrates.
c.proteins.
d.nucleic acids.
11.Explain the relationship between an enzyme
and the activation energy of the reaction in
which the enzyme participates.
12.Look at the water strider in the photograph
below. Using what you have learned about
the properties of water, explain how the
insect can stand on the water’s surface.- Ruby-throated humming-
birds migrate 2,000 km every fall. Before
migrating, they eat nectar and convert
much of the sugar in the nectar to fat. Why
is it advantageous for these birds to store
energy as fat rather than as glycogen?
14.Describe how molecules such as carbohy-
drates and lipids are important in home-
ostasis. (Hint:See Chapter 1, Section 1.) - Concept MappingMake a concept
map that illustrates the structure of matter.
Include the following key terms in your
map:atom, element, compound, molecule,
and ion.
Performance
ZONE
44 CHAPTER 2Review
CHAPTER REVIEW
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