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Unit 1: Chemistry



Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

 1. 

Which of the following is true regarding deoxyribonucleic acid (DNA)?
a.
Each deoxyribonucleic acid molecule is composed of two long chains of nucleotides arranged in a double helix.
b.
Genes are composed of deoxyribonucleic acid.
c.
DNA is composed of chemical building blocks called nucleotides.
d.
Only A and C are correct.
e.
A, B, and C are correct.
 

 2. 

Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of
a.
a bioinformatic system.
b.
positive feedback.
c.
negative feedback.
d.
feedback inhibition.
e.
both C and D
 

 3. 

Which of these provides evidence of the common ancestry of all life?
a.
the ubiquitous use of catalysts by living systems
b.
the universality of the genetic code
c.
the structure of the nucleus
d.
the structure of cilia
e.
the structure of chloroplasts
 

 4. 

Through time, the lineage that led to modern whales shows a change from four-limbed land animals to aquatic animals with two limbs that function as flippers. This change is best explained by
a.
natural philosophy.
b.
creationism.
c.
the hierarchy of the biological organization of life.
d.
natural selection.
e.
feedback inhibition.
 

 5. 

Why is it important that an experiment include a control group?
a.
The control group is the group that the researcher is in control of; it is the group in which the researcher predetermines the nature of the results.
b.
The control group provides a reserve of experimental subjects.
c.
A control group is required for the development of an "if; then" statement.
d.
A control group assures that an experiment will be repeatable.
e.
Without a control group, there is no basis for knowing if a particular result is due to the variable being tested or to some other factor.
 

 6. 

Which of the following is not a theme that unifies biology?
a.
interaction with the environment
b.
emergent properties
c.
evolution
d.
reductionism
e.
structure and function
 

 7. 

About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?
a.
carbon, sodium, chlorine, nitrogen
b.
carbon, sulfur, phosphorus, hydrogen
c.
oxygen, hydrogen, calcium, sodium
d.
carbon, hydrogen, nitrogen, oxygen
e.
carbon, oxygen, sulfur, calcium
 

 8. 

What is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15 electrons?
a.
15 daltons
b.
16 daltons
c.
30 daltons
d.
31 daltons
e.
46 daltons
 

 9. 

When two atoms are equally electronegative, they will interact to form
a.
equal numbers of isotopes.
b.
ions.
c.
polar covalent bonds.
d.
nonpolar covalent bonds.
e.
ionic bonds.
 

 10. 

Which of the following best describes chemical equilibrium?
a.
Forward and reverse reactions continue with no effect on the concentrations of the reactants and products.
b.
Concentrations of products are higher than the concentrations of the reactants.
c.
Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products.
d.
Reactions stop only when all reactants have been converted to products.
e.
There are equal concentrations of reactants and products, and the reactions have stopped.
 

 11. 

An example of a hydrogen bond is the bond between
a.
C and H in methane (CH4).
b.
the H of one water molecule and the O of another water molecule.
c.
Na+and Cl- in salt.
d.
the two hydrogen atoms in a molecule of hydrogen gas (H2).
e.
Mg+and Cl- in MgCl2.
 

 12. 

Which of the following is true when an ice cube cools a drink?
a.
Molecule collisions in the drink increase.
b.
Kinetic energy in the drink decreases.
c.
A calorie of heat energy is transferred from the ice to the water of the drink.
d.
The specific heat of the water in the drink decreases.
e.
Evaporation of the water in the drink increases.
 

 13. 

What would be the pH of a solution with a hydroxide ion [OH-] concentration of 10-12 M?
a.
pH 2
b.
pH 4
c.
pH 10
d.
pH 12
e.
pH 14
 

 14. 

The concept of vitalism is based on a belief in a life force outside the jurisdiction of physical and chemical laws. According to this belief, organic compounds can arise only within living organisms. Which of the following did the most to refute the concept of vitalism?
a.
Wöhler's synthesis of urea
b.
Berzelius's distinction between organic and inorganic compounds
c.
Miller's experiments with ancient atmospheres
d.
Rodriguez's studies of phytochemicals
e.
Kolbe's synthesis of acetic acid
 

 15. 

Which of the following is (are) true about the carbon atoms present in all organic molecules?
a.
They were incorporated into organic molecules by plants.
b.
They were processed into sugars through photosynthesis.
c.
They are ultimately derived from carbon dioxide.
d.
Only A and C are correct.
e.
A, B, and C are correct.
 

 16. 

Which two functional groups are always found in amino acids?
a.
ketone and aldehyde
b.
carbonyl and carboxyl
c.
carboxyl and amino
d.
phosphate and sulfhydryl
e.
hydroxyl and aldehyde
 
 
Use the molecules shown in the figure below to answer the following questions..

unit1_chemistry_files/i0180000.jpg
 

 17. 

Which molecule functions to transfer energy between organic molecules?
a.
Molecule A
b.
Molecule B
c.
Molecule C
d.
Molecule D
e.
Molecule E
 

 18. 

Polymers of polysaccharides, fats, and proteins are all synthesized from monomers by which process?
a.
connecting monosaccharides together (condensation reactions)
b.
the addition of water to each monomer (hydrolysis)
c.
the removal of water (dehydration reactions)
d.
ionic bonding of the monomers
e.
the formation of disulfide bridges between monomers
 

 19. 

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?
a.
as a pentose
b.
as a hexose
c.
as a monosaccharide
d.
as a disaccharide
e.
as a polysaccharide
 

 20. 

The molecule shown in the figure below is a

unit1_chemistry_files/i0220000.jpg

a.
polysaccharide.
b.
polypeptide.
c.
saturated fatty acid.
d.
triacylglycerol.
e.
unsaturated fatty acid.
 

 21. 

Polysaccharides, lipids, and proteins are similar in that they
a.
are synthesized from monomers by the process of hydrolysis.
b.
are synthesized from monomers by dehydration reactions.
c.
are synthesized as a result of peptide bond formation between monomers.
d.
are decomposed into their subunits by dehydration reactions.
e.
all contain nitrogen in their monomer building blocks.
 

 22. 

All of the following molecules are proteins except
a.
hemoglobin.
b.
transthyretin.
c.
collagen.
d.
lysozyme.
e.
glycogen.
 

 23. 

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA
a.
is a six-carbon sugar and the sugar in RNA is a five-carbon sugar.
b.
can form a double-stranded molecule.
c.
has a six-membered ring of carbon and nitrogen atoms.
d.
can attach to a phosphate.
e.
contains one less oxygen atom.
 



 
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