73
CHAPTER TWO
Chemical Basis of Life
(4) The protein’s conformation determines its
function.
(5) Exposure to excessive heat, radiation,
electricity, or certain chemicals can denature
proteins.
d. Nucleic acids constitute genes, the instructions
that control cell activities, and direct protein
synthesis.
(1) The two types are RNA and DNA.
(2) Nucleic acid molecules are composed of
building blocks called nucleotides.
(3) DNA molecules store information used by
cell parts to construct speciF
c types of protein
molecules.
(4) RNA molecules help synthesize proteins.
(5) DNA molecules are replicated, and an exact
copy of the original cell’s DNA is passed to
each of the newly formed cells resulting from
cell division.
2. Organic substances
a. Carbohydrates provide much of the energy cells
require; their building blocks are simple sugar
molecules.
b. Lipids, such as fats, phospholipids, and steroids,
supply energy and are used to build cell parts;
their building blocks are molecules of glycerol and
fatty acids.
c. Proteins serve as structural materials, energy
sources, hormones, cell surface receptors,
antibodies, and enzymes that initiate or speed
chemical reactions without being consumed.
(1) The building blocks of proteins are amino
acids.
(2) Proteins vary in the numbers and types of their
constituent amino acids; the sequences of
these amino acids; and their three-dimensional
structures, or conformations.
(3) The amino acid sequence determines the
protein’s conformation.
2.1 Introduction
1
Def
ne
chemistry
. (p. 51)
2
Explain the diF
erence between chemistry and
biochemistry. (p. 51)
2.2 Structure of Matter
3
Def
ne
matter
. (p. 51)
4
Def
ne
compound
. (p. 52)
5
List the ±our most abundant elements in the human body.
(p. 52)
6
Explain the relationship between elements and atoms.
(p. 52)
7
Identi±y the major parts o± an atom and where they are
±ound within an atom. (p. 52)
8
Distinguish between protons and neutrons. (p. 52)
9
Explain why a complete atom is electrically neutral. (p. 52)
10
Distinguish between atomic number and atomic weight.
(p. 52)
11
Def
ne
isotope
. (p. 53)
12
Def
ne
atomic radiation.
(p. 53)
13
Explain the relationship between molecules and
compounds. (p. 53)
14
Explain how electrons are distributed within the electron
shells o± atoms. (p. 55)
15
Explain why some atoms are chemically inert. (p. 55)
16
An ionic bond ±orms when _____________. (p. 55)
a. atoms share electrons
b. positively-charged and negatively-charged parts o±
covalent molecules attract
c. ions with opposite electrical charges attract
d. two atoms exchange protons
e. an element has two types o± isotopes
CHAPTER ASSESSMENTS
17
A covalent bond ±orms when _____________. (p. 56)
a. atoms share electrons
b. positively-charged and negatively-charged parts o±
covalent molecules attract
c. ions with opposite electrical charges attract
d. two atoms exchange protons
e. an element has two types o± isotopes
18
Distinguish between a single covalent bond and a double
covalent bond. (p. 57)
19
Show the diF
erence between the molecular ±ormula and
the structural ±ormula o± a specif
c compound. (p. 57)
20
Explain how a hydrogen bond ±orms. (p. 57)
21
Identi±y two types o± macromolecules in which hydrogen
bonds are important parts o± the structure. (p. 58)
22
Identi±y three major types o± chemical reactions. (p. 58)
23
Def
ne
reversible reaction
.
(p. 59)
24
Def
ne
catalyst
.
(p. 59)
25
Def
ne
electrolyte,
acid, base,
and
salt
. (p. 59)
26
Explain pH and how to use the pH scale. (p. 59)
27
Def
ne
buf
er
. (p. 60)
2.3 Chemical Constituents of Cells
28
Distinguish between inorganic and organic substances.
(p. 60)
29
Distinguish between electrolytes and nonelectrolytes.
(p. 60)
30
Describe the ±unctions o± water and oxygen in the human
body. (p. 61)
31
List several ions that cells require and identi±y their
±unctions. (p. 61)
32
Def
ne
electrolyte
balance
. (p. 61)
33
Describe the general characteristics o± carbohydrates.
(p. 62)
(5
6
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