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1. Which of the following statements is false?
A) An atom is the smallest unit of an element that still retains the properties of the element.
B) The neutrons and protons present in the nucleus of an atom are almost identical in mass; each
has a mass of about 1 dalton.
C) All atoms of a particular element have the same number of protons in their nuclei.
D) Atoms of the various elements differ in their number of subatomic particles.
E) Protons and electrons are electrically charged particles. Protons have one unit of
negative charge, and electrons have one unit of positive charge.
2. Each element is unique and different from other elements because of the number of protons in
the nuclei of its atoms. Which of the following indicates the number of protons in an atom’s
nucleus?
A) atomic weight
B) mass number
C) atomic mass
D) atomic number
E) mass weight
3) What is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15
electrons?
A) 30 daltons
B) 46 daltons
C) 15 daltons
D) 31 daltons
E) 16 daltons
4. Which drawing depicts the electron configuration of nitrogen
( 14 N)?
7
Answer: B
5. What is the maximum number of covalent bonds an element with atomic number 8 can
make with hydrogen?A) 1
B) 2 C) 3
D) 4
E) 6
6. The ionic bond of sodium chloride is formed when
A) sodium and chlorine both lose electrons from their outer valence shells.
B) chlorine gains an electron from sodium.
C) chlorine gains a proton from sodium.
D) sodium and chlorine share an electron pair.
E) sodium gains an electron from chlorine.
7. In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom
by
A) hydrogen bonds.
B) van der Waals interactions.
C) polar covalent bonds.
D) nonpolar covalent bonds.
E) ionic bonds.
8. One mole (mol) of a substance isA) 6.02 x 10^23 molecules of the substance.
B) 1 g of the substance dissolved in 1 L of solution.
C) the largest amount of the substance that can be dissolved in 1 L of solution.
D) the molecular mass of the substance expressed in grams.
E) A and D only
9. Which of the following ionizes completely in solution and is considered to be a strong base
(alkali)?
A) NH3
B) HCl
C) NaCl
D) NaOH
E) H2CO3
10) A given solution contains 0.0001(10-4) moles of hydrogen ions [H+] per liter. Which of the
following best describes this solution?
A) neutral
B) basic: H+ acceptor
C) acidic: H+ donor
D) acidic: H+ acceptor
E) basic: H+ donor
11) Buffers are substances that help resist shifts in pH by
A) releasing OH- in basic solutions.
B) donating H+ to a solution when they have been depleted.
C) releasing H+ in acidic solutions.
D) accepting H+ when the are in excess.
E) Both B and D are correct.
12) Pure, freshly-distilled water has a pH of 7. This means that
A) there are no H+ ions in the water.
B) The concentration of OH- ions in the water is 7 times the concentration of H+ ions in the
water.
C) there are no OH- ions in the water.
D) the concentration of H+ ions in the water is 7 times the concentration of OH- ions in the
water.
E) the concentration of H+ ions in the water equals the concentration of OH- ions in the
water.
13) The two molecules shown in Figure 4.1 are best described as
A) structural isomers.
B) nonradioactive isotopes.
C) geometric isomers.
D) radioactive isotopes.
E) optical isomers.
14) Which is the best description of a carbonyl group?
A) a nitrogen and two hydrogens joined to a carbon by covalent bonds
B) a carbon atom joined to an oxygen by a double covalent bond
C) a sulfur and a hydrogen joined to a carbon by covalent bonds
D) an oxygen joined to a carbon by a single covalent bond
E) a carbon joined to two hydrogens by single covalent bonds
15) Which molecule is water soluble because it has a hydroxyl functional group?
Answer: A
16) For this pair of items, choose the option that best describes their relationship.
(A) The number of purines in the DNA strand 5′-AAGAGGAGAAA-3′
(B) The number of pyrimidines in the DNA strand 5′-AAGAGGAGAAA-3′
A) Item (A) is exactly or very approximately equal to item (B).
B) Item (A) is less than item (B).
C) Item (A) is greater than item (B).
D) Item (A) may stand in more than one of the above relations to item (B).
17) Which of the following is not a polymer?
A) chitin
B) glucose C) starch
D) cellulose
E) DNA
18) Which of the following best summarizes the relationship between dehydration reactions and
hydrolysis?
A) Macromolecular synthesis occurs through the removal of water and digestion occurs through
the addition of water.
B) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
C) Dehydration reactions can occur only after hydrolysis.
D) Hydrolysis creates monomers, and dehydration reactions break down polymers.
E) A and B are correct.
19) Which of the following is a false statement concerning amino groups?
A) They are nonpolar.
B) They are found in amino acids.
C) They are basic in pH.
D) They contain nitrogen.
E) They are components of urea.
20) Which of the following statements is true regarding the molecule illustrated in Figure 5.2?
A) It is a saturated fatty acid.
B) A diet rich in this molecule may contribute to atherosclerosis.
C) Molecules of this type are usually liquid at room temperature.
D) A and B only
E) A, B and C
21) Which molecule has a carbonyl functional group in the form of an aldehyde?
Answer: B
22. Which of the following is true of both starch and cellulose?A) They are geometric
isomers of each other.
B) They are both used for energy storage in plants.
C) They are both polymers of glucose.
D) They are both structural components of the plant cell wall.
E) They can both be digested by humans.
23. All of the following contain amino acids exceptA) enzymes.
B) antibodies.
C) cholesterol.
D) hemoglobin.
E) insulin.
24. Which type of interaction stabilizes the alpha (!) helix and the beta (“) pleated sheet
structures of proteins?A) hydrogen bonds
B) hydrophobic interactions
C) peptide bonds
D) nonpolar covalent bonds
E) ionic bonds
25. The R group or side chain of the amino acid serine is —CH2″OH. The R group or side
chain of the amino acid alanine is —CH3. Where would you expect to find these amino
acids in a globular protein in aqueous solution?
A) Alanine would be in the interior, and serine would be on the exterior of the
globular protein.
B) Both serine and alanine would be in the interior and on the exterior of the globular
protein.
C) Both serine and alanine would be on the exterior of the globular protein.
D) Both serine and alanine would be in the interior of the globular protein.
E) Serine would be in the interior, and alanine would be on the exterior of the globular
protein.
26) In the double helix structure of nucleic acids, cytosine hydrogen bonds to
A) guanine.
B) adenine.
C) thymine.
D) ribose.
E) deoxyribose.
27) If a DNA sample were composed of 10% thymine, what would be the percentage of
guanine?
A) 80
B) impossible to tell from the information given
C) 20
D) 40
E) 10
28) Which of the following are nitrogenous bases of the pyrimidine type?
A) cytosine and uracil
B) adenine and thymine
C) ribose and deoxyribose
D) guanine and adenine
E) thymine and guanine
29) Altering which of the following levels of structural organization could change the function of
a protein?
A) secondary
B) tertiary
C) primary
D) quaternary
E) all of the above
30) Which of the following molecules consists of a hydrophilic “head” region and a hydrophobic
“tail” region?
A) 7
B) 11
C) 5
D) 2
E) 9