Chapter 2
Chemistry Comes Alive
59
2
24.
Some energy is lost in every energy conversion. Explain the
meaning of this statement. (Direct your response to answering
the question: Is it really lost? If not, what then?)
25.
Provide the atomic symbol for each of the following elements:
(a) calcium, (b) carbon, (c) hydrogen, (d) iron, (e) nitrogen,
(f) oxygen, (g) potassium, (h) sodium.
26.
Consider the following information about three atoms:
12
6
C
13
6
C
14
6
C
(a) How are they similar to one another? (b) How do they differ
from one another? (c) What are the members of such a group of
atoms called? (d) Using the planetary model, draw the atomic
configuration of
12
6
C showing the relative position and numbers of
its subatomic particles.
27.
How many moles of aspirin, C
9
H
8
O
4
, are in a bottle containing
450 g by weight? (
Note
: Te approximate atomic weights of its
atoms are C
5
12, H
5
1, and O
5
16.)
28.
Given the following types of atoms, decide which type of
bonding, ionic or covalent, is most likely to occur: (a) two oxygen
atoms; (b) four hydrogen atoms and one carbon atom; (c) a
potassium atom (
39
19
K) and a fluorine atom (
19
9
F).
29.
What are hydrogen bonds and how are they important in the body?
30.
Te following equation, which represents the oxidative
breakdown of glucose by body cells, is a reversible reaction.
Glucose
1
oxygen
S
carbon dioxide
1
water
1
A±P
(a) How can you indicate that the reaction is reversible? (b) How
can you indicate that the reaction is in chemical equilibrium?
(c) Define chemical equilibrium.
31.
Differentiate clearly between primary, secondary, and tertiary
protein structure.
32.
Dehydration and hydrolysis reactions are essentially opposite
reactions. How are they related to the synthesis and degradation
(breakdown) of biological molecules?
33.
Describe the mechanism of enzyme action.
34.
Explain the importance of molecular chaperones.
35.
Explain why, if you pour water into a glass very carefully, you can
“stack” the water slightly above the rim of the glass.
Critical Thinking
and Clinical Application
Questions
1.
As Ben jumped on his bike and headed for the freshwater lake,
his mother called a²er him, “Don’t swim if we have an electrical
storm—it looks threatening.” Tis was a valid request. Why?
2.
Some antibiotics act by binding to certain essential enzymes in the
target bacteria. (a) How might these antibiotics influence the chemical
reactions controlled by the enzymes? (b) What is the anticipated effect
on the bacteria? On the person taking the antibiotic prescription?
3.
Mrs. Roberts, in a diabetic coma, has just been admitted to Noble
Hospital. Her blood pH indicates that she is in severe acidosis,
and measures are quickly instituted to bring her blood pH back
within normal limits. (a) Define pH and note the normal pH of
blood. (b) Why is severe acidosis a problem?
4.
Jimmy, a 12-year-old boy, was awakened suddenly by a loud
crash. As he sat up in bed, straining to listen, his fright was
revealed by his rapid breathing (hyperventilation), a breathing
pattern effective in ridding the blood of CO
2
. At this point, was
his blood pH rising or falling?
5.
A²er you eat a protein bar, which chemical reactions introduced
in this chapter must occur for the amino acids in the protein bar
to be converted into proteins in your body cells?
8.
Which of the following does
not
describe a mixture?
(a)
properties of its components are retained,
(b)
chemical
bonds are formed,
(c)
components can be separated physically,
(d)
includes both heterogeneous and homogeneous examples.
9.
In a beaker of water, the water-water bonds can properly be called
(a)
ionic bonds,
(b)
polar covalent bonds,
(c)
nonpolar covalent
bonds,
(d)
hydrogen bonds.
10.
When a pair of electrons is shared between two atoms, the bond
formed is called
(a)
a single covalent bond,
(b)
a double covalent
bond,
(c)
a triple covalent bond,
(d)
an ionic bond.
11.
Molecules formed when electrons are shared unequally are
(a)
salts,
(b)
polar molecules,
(c)
nonpolar molecules.
12.
Which of the following covalently bonded molecules are polar?
Cl
H
C
H
H
H
H
C
Cl
Cl
H
Cl
N
N
(a)
(b)
(c)
(d)
13.
Identify each reaction as one of the following:
(a)
a synthesis
reaction,
(b)
a decomposition reaction,
(c)
an exchange reaction.
______________
(1)
2Hg
1
O
2
S
2HgO
______________
(2)
HCl
1
NaOH
S
NaCl
1
H
2
O
14.
Factors that accelerate the rate of chemical reactions include all
but
(a)
the presence of catalysts,
(b)
increasing the temperature,
(c)
increasing the particle size,
(d)
increasing the concentration of
the reactants.
15.
Which of the following molecules is an inorganic molecule?
(a)
sucrose,
(b)
cholesterol,
(c)
collagen,
(d)
sodium chloride.
16.
Water’s importance to living systems reflects
(a)
its polarity
and solvent properties,
(b)
its high heat capacity,
(c)
its high
heat of vaporization,
(d)
its chemical reactivity,
(e)
all of
these.
17.
Acids
(a)
release hydroxyl ions when dissolved in water,
(b)
are
proton acceptors,
(c)
cause the pH of a solution to rise,
(d)
release
protons when dissolved in water.
18.
A chemist, during the course of an analysis, runs across a
chemical composed of carbon, hydrogen, and oxygen in the
proportion 1:2:1 and having a six-sided molecular shape. It is
probably
(a)
a pentose,
(b)
an amino acid,
(c)
a fatty acid,
(d)
a monosaccharide,
(e)
a nucleic acid.
19.
A triglyceride consists of
(a)
glycerol plus three fatty acids,
(b)
a sugar-phosphate backbone to which two amino groups are
attached,
(c)
two to several hexoses,
(d)
amino acids that have
been thoroughly saturated with hydrogen.
20.
A chemical has an amine group and an organic acid group.
It does not, however, have any peptide bonds. It is
(a)
a
monosaccharide,
(b)
an amino acid,
(c)
a protein,
(d)
a fat.
21.
Te lipid(s) used as the basis of vitamin D, sex hormones, and
bile salts is/are
(a)
triglycerides,
(b)
cholesterol,
(c)
phospholipids,
(d)
prostaglandin.
22.
Enzymes are organic catalysts that
(a)
alter the direction in
which a chemical reaction proceeds,
(b)
determine the nature of
the products of a reaction,
(c)
increase the speed of a chemical
reaction,
(d)
are essential raw materials for a chemical reaction
that are converted into some of its products.
Short Answer Essay Questions
23.
Define or describe energy, and explain the relationship between
potential and kinetic energy.
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