PCC Biochemistry 2011

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PCC Biochemistry 2011
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 1.
The three particles that make up atoms are
a.
protons, neutrons, and isotopes.
c.
positives, negatives, and electrons.
b.
neutrons, isotopes, and electrons.
d.
protons, neutrons, and electrons.
 2.
The space surrounding the nucleus of an atom contains
a.
protons.
c.
neutrons.
b.
electrons.
d.
ions.
 3.
Democritus believed that atoms
a.
were composed of electrons.
c.
could be divided.
b.
were composed of protons.
d.
could not be divided.
 4.
If an atom contains 3 protons, 4 neutrons,  and 3 electrons, its mass number would be
a.
3.
c.
7.
b.
4.
d.
11.
 5.
If a chlorine atom had 17 protons and 18 neutrons, it would be called
a.
chlorine-17.
c.
chlorine-35.
b.
chlorine-18.
d.
chlorine-1.
 6.
Isotopes are atoms of the same element with the same number of protons and
a.
a different number of electrons.
c.
a different number of neutrons.
b.
a different number of molecules.
d.
the same number of neutrons.
 7.
Which of the following is a use of radioactive isotopes?
a.
can determine the ages of rocks and fossils
b.
can be used to treat cancer and kill bacteria that cause food to spoil
c.
can be used as “tracers” to follow the movements of substances within organisms
d.
all of the above
 8.
If an atom contains 11 protons and 12 neutrons, its atomic number is
a.
1.
c.
12.
b.
11.
d.
23.
 9.
Which of the following terms describes a substance formed by the combination of two or more elements in definite proportions?
a.
compound
c.
nucleus
b.
isotope
d.
enzyme
 10.
Which of the following makes up a molecule of water?
a.
one atom of hydrogen and one atom of oxygen
b.
one atom of sodium and one atom of chlorine
c.
one atom of hydrogen and two atoms of oxygen
d.
two atoms of hydrogen and one atom of oxygen
 11.
Which of the following is NOT true about chlorine?
a.
It is a poisonous, greenish gas.
b.
It combines with sodium to form table salt.
c.
It was used to kill many soldiers in World War I.
d.
It is not reactive.
 12.
Which of the following statements about a compound is true?
a.
The physical and chemical properties of a compound are usually very different from those of the elements from which it is formed.
b.
Only the physical properties of a compound are usually the same as those of the elements from which it is formed.
c.
Only the chemical properties of a compound are usually the same as those of the elements from which it is formed.
d.
The physical and chemical properties of a compound are usually the same as those of the elements from which it is formed.
 13.
A covalent bond is formed as the result of
a.
transferring electrons.
c.
transferring protons.
b.
sharing an electron pair.
d.
sharing a proton pair.
 14.
Which term does NOT apply to sodium chloride?
a.
molecule
c.
compound
b.
ionic bonding
d.
crystal
 15.
What type of electron is available to form bonds?
a.
valence
c.
ionic
b.
nucleus
d.
covalent
 16.
What type of ion forms when an atom loses electrons?
a.
neutral
c.
negative
b.
positive
d.
possibly positive or negative
 17.
Ice floats on water because
a.
of cohesion.
c.
water shrinks when it freezes.
b.
ice has a higher density than water.
d.
water expands when it freezes.
 18.
The most abundant compound in most living things is
a.
carbon dioxide.
c.
sodium chloride.
b.
water.
d.
sugar.
 19.
Water molecules are polar, with the
a.
oxygen side being slightly positive and the hydrogen side being slightly negative.
b.
oxygen and hydrogen sides being slightly positive.
c.
oxygen and hydrogen sides being slightly negative.
d.
oxygen side being slightly negative and the hydrogen side being slightly positive.
 20.
In a water molecule, shared electrons spend more time around the oxygen atom than the hydrogen atoms.  As a result, the oxygen atom is
a.
slightly negative.
c.
slightly positive.
b.
very negative.
d.
very positive.
 21.
A solution is a(an)
a.
combination of isotopes.
b.
chemical reaction.
c.
evenly distributed mixture of two or more substances.
d.
combination of two or more liquids.
 22.
If you stir salt into boiling water, you produce a
a.
mixture called a suspension.
c.
solution and suspension.
b.
mixture called a solution.
d.
mixture only.
 23.
When salt is dissolved in water, water is the
a.
reactant.
c.
solute.
b.
solution.
d.
solvent.
 24.
While preparing a cell culture, a scientist places a colony of bacteria into distilled water and stirs it up.  This mixture of water and living cells would best be called a(an)
a.
solution.
b.
suspension.
c.
buffer.
d.
adhesion.
 25.
If the pH of stomach acid and of oven cleaner were measured,
a.
both would be below 7.
b.
both would be above 7.
c.
the pH of stomach acid would be above 7, but the pH of oven cleaner would be below 7.
d.
the pH of stomach acid would be below 7, but the pH of oven cleaner would be above 7.
 26.
A map of eastern North America, showing the pH of rainfall in the various states, indicates that the pH of rain in New York State varies from 4.22 to 4.40. According to these figures, the most acidic rainfall in New York State has a pH of
a.
4.22.
c.
4.35.
b.
4.30.
d.
4.40.
 27.
A substance with a pH of 6 is called
a.
an acid.
c.
both an acid and a base.
b.
a base.
d.
neither an acid nor a base.
 28.
Solutions that contain concentrations of H+ ions lower than pure water
a.
have pH values below 7.
c.
are bases.
b.
are acids.
d.
are enzymes.
 29.
Amino acid is to protein as
a.
fat is to lipid.
c.
sugar is to fat.
b.
DNA is to RNA.
d.
simple sugar is to starch.
 30.
A monosaccharide is a
a.
carbohydrate.
c.
nucleic acid.
b.
lipid.
d.
protein.
 31.
Which of the following is NOT a monomer?
a.
a glucose molecule
c.
a nucleotide
b.
an amino acid
d.
a protein
 32.
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 and regulate cell processes
d.
build tissues such as bone and muscle
 33.
Which statement is true?
a.
Simple sugars are made of polysaccharides.
b.
Glycerol is made of fatty acids.
c.
RNA molecules are made of nucleotides.
d.
Amino acids are made of proteins.
 34.
In chemical reactions, atoms are
a.
created.
c.
rearranged.
b.
destroyed.
d.
neutralized.
 35.
When hydrogen and oxygen combine to form water, water is
a.
a product.
c.
both a product and a reactant.
b.
a reactant.
d.
neither a product nor a reactant.
 36.
Identify the reactant(s) in the chemical reaction, CO2 + H2O ® H2CO3.
a.
CO2, H2O, and H2CO3
c.
H2CO3
b.
CO2 and H2O
d.
CO2
 37.
What is the process that changes one set of chemicals into another set of chemicals?
a.
cohesion
c.
chemical reaction
b.
adhesion
d.
dissolving
 38.
What is the term used to describe the energy needed to get a reaction started?
a.
adhesion energy
c.
cohesion energy
b.
activation energy
d.
chemical energy
 39.
Chemical reactions that release energy
a.
will not occur.
c.
will always explode.
b.
will never explode.
d.
often occur spontaneously.
 40.
If a reaction in one direction releases energy, the reaction in the opposite direction
a.
also releases energy.
c.
destroys energy.
b.
absorbs energy.
d.
cannot occur.
 41.
Which of the following is a form of energy that may be released during a chemical reaction?
a.
heat
c.
light
b.
sound
d.
all of the above
 42.
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.
 43.
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.
 44.
A substance that accelerates the rate of a chemical reaction is called a(an)
a.
catalyst.
c.
molecule.
b.
lipid.
d.
element.
 45.
Enzymes affect the reactions in living cells by changing the
a.
products of the reaction.
c.
temperature of the reaction.
b.
speed of the reaction.
d.
pH of the reaction.
 

Short Answer
 46.
Why are atoms considered neutral?

 47.
What is a molecule?

 

Other

USING SCIENCE SKILLS

 

pH Values of Some Common Substances
Substance pH
Hydrochloric acid
1.0
Sulfuric acid
1.2
Tomatoes
4.2
Rainwater
6.2
Pure water
7.0
Sea water
8.5
Ammonium chloride
11.1
Sodium hydroxide
13.0

Figure 2–2
 48.
Applying Concepts What is the strongest acid listed in Figure 2–2?

 49.
Applying Concepts What is the pH of the strongest base listed in Figure 2–2?

 50.
Applying Concepts Using your knowledge of the pH scale, which of the chemicals in Figure 2-2 has the lowest concentration of H+ ions?

 

        
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