Download Big Idea 2 Exam - C2-5

Practice questions – Big Idea 2
____
1. Which of the following statements about atoms is false?
a. Atoms are mostly empty space.
b. Protons, neutrons, and electrons have approximately the same mass.
c. The nucleus is positively charged due to the presences of protons.
d. The further an electron is from the nucleus, the greater its potential energy.
____
2. The chemical behavior of an atom is determined most directly by the:
a. atomic number.
c. the number of valence electrons.
b. number of energy levels.
d. the total number of electrons.
____
3. If atom “X” contains 14 protons, 13 electrons, and 12 neutrons, and atom “Y” contains 14
protons, 14 electrons, and 12 neutrons, then you conclude that:
a. X and Y are isotopes of the same element.
b. X and Y are atoms of the same element.
c. X and Y both have filled valence shells.
d. X is an ion, but Y is not.
____
4. Van der Waals interactions result when
a. a hydrogen atom loses an electron.
b. electrons are not symmetrically distributed in a molecule.
c. molecules held by ionic bonds react with water.
d. two polar covalent bonds react.
____
5. Which of the following best describes a dynamic chemical equilibrium, as is shown for the
reversible chemical reaction below involving the salt barium chloride?
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 reach equilibrium only when all reactants have been converted to products
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6. Which of the following drawings best represents a water molecule?
a.
c.
+
+
-
-
+
+
b.
+
-
d.
-
+
-
____
7. In a lake, mineral nutrients accumulate at the bottom while the amount of dissolved oxygen is
greater near the surface. What property of water accounts for the mixing of surface and bottom
waters (turnover) during the annual temperature fluctuations as a result of the seasons?
a. Individual water molecules move less rapidly as water cools.
b. As warm water cools, it reaches its greatest density at 4°C; further cooling of
water (between 4 and 0°C) results in a decrease in density.
c. Water changes from liquid to solid at 0°C.
d. The distance between water molecules is greater in ice than in liquid form.
____
8. What is the pH of a solution with a hydrogen ion [H ] concentration of 10
a. pH 2
c. pH 6
b. pH 4
d. pH 8
____
9. One liter of a solution of pH 2 has how many more hydrogen ions (H ) than 1 L of a solution of
pH 6?
a. 3 times more
c. 1,000 times more
b. 100 times more
d. 10,000 times more
pH Values of Some Common
Substances
Substance
Hydrochloric acid
Sulfuric acid
Tomatoes
pH
1.0
1.2
4.2
M?
Rainwater
Pure water
Sea water
Ammonium chloride
Sodium hydroxide
6.2
7.0
8.5
11.1
13.0
____ 10. According to the pH values in the above table, the solution which has as many hydrogen ions
(H+) as hydroxide ions (OH-) is
a. hydrochloric acid
c. sodium hydroxide
b. pure water
d. sea water
____ 11. The weakest acid listed in the above table is
a. hydrochloric acid
c. rainwater
b. tomatoes
d. pure water
____ 12. A mole of table sugar and a mole of vitamin C are equal in their
a. mass in daltons.
c. number of molecules.
b. mass in grams.
d. number of atoms.
____ 13. Three of the following illustrations depict different structural isomers of the organic compound
with the molecular formula
. For clarity, only the carbon skeletons are shown; hydrogen
atoms that would be attached to the carbons have been omitted. Which one is NOT a structural
isomer of this compound?
a.
c.
b.
d.
____ 14. Based on the five molecules displayed above (A-E), which one(s) contain(s) a carbonyl group?
a. A
c. D
b. B and C
d. E
____ 15. Based on the five molecules displayed above (A-E), which one(s) is (are) considered an organic
acid?
a. A
c. D
b. B and C
d. E
____ 16. One of the buffers that contribute to pH stability in human blood is carbonic acid (
).
Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO ) and a hydrogen ion
(H+) according to the following chemical equation:
H2CO3 <--> HCO3- + H+
If the pH of the blood drops, one would expect
a. the concentration of the hydroxide ion (OH-) to decrease.
b. the concentration of the hydroxide ion (OH-) to increase.
c. the H2CO3 to act as an acid and release H+ with the formation of HCO3-.
d. the HCO3- to act as a base and remove excess H+ with the formation of H2CO3.
____ 17. Why are hydrocarbons insoluble in water?
a. The majority of their bonds are polar covalent carbon-to-hydrogen linkages.
b. The majority of their bonds are nonpolar covalent carbon-to-carbon linkages.
c. They are hydrophilic.
d. They exhibit considerable molecular complexity and diversity.
____ 18. Research indicates that Albuterol, a drug used to relax bronchial muscles, improving airflow and
thus offering relief from asthma, consists only of one enantiomer, the R-form. Why is it
important for this drug to consist of only one enantiomeric form, rather than a mixture of
enantiomers?
a. Different enantiomers may have different or opposite physiological effects.
b. It is impossible to synthesize mixtures of enantiomers.
c. It is much less expensive to synthesize one enantiomer at a time.
d. Albuterol is an example of a compound for which only one enantiomer exists.
Read each question carefully and choose the BEST answer.
WRITE ALL ANSWERS ON THE ANSWER SHEET
____
1.
The process illustrated in the picture
on the right is called:
a. condensation
b. denaturation
c. hydrolysis
d. polymerization
____
2. The products of the process in the picture above
a. store amino acids.
b. supply cells with energy and carbon skeletons.
c. function as hormones.
d. speed up chemical reactions.
____
3. The molecule depicted in the above diagram is a
a. polynucleotide
c. polysaccharide
b. lipid
d. polypeptide
____
4. Each organism is uniquely adapted to its environment even at the molecular level. Human fats
are about 3% polyunsaturated while that of cod, a fish living in cold ocean waters, is
approximately 50% polyunsaturated. Which of the following contributes to the cod’s ability to
survive in extremely cold waters?
a. Unsaturated fats act as hormones activating genes for proteins that act as
insulators.
b. Unsaturated fats dissolve in the aqueous portions of cells acting like antifreeze and
slow the formation of ice crystals.
c. Unsaturated fats remain fluid at lower temperatures than saturated fats due to their
shape.
d. Unsaturated fats can be assembled into thicker cell membranes providing
additional insulation against the cold
____
5. Symbiotic protists in the gut of termites can hydrolyze the cellulose in wood. What molecule
then becomes available to both host and symbiont?
a. glucose
c. glycerol and fatty acid
b. glucose and fructose
d. nucleotides
____ 6.
What i
What is the structure shown in the
picture on the right?
a. cholesterol
b. DNA
c. hemoglobin
d. glycogen
d.
____
7. Molecular chaperones are proteins that mediate the folding process of:
a. other proteins.
c. lipids.
b. amino acids.
d. DNA.
____
8. The structural level of a protein least affected by a disruption in hydrogen bonding is the
a. primary level.
c. tertiary level.
b. secondary level.
d. quaternary level.
____ 9.
What
The ester bond located within the
molecule on the right is labeled:
a. A
b. B.
c. C.
d. D.
____ 10. The molecule above is
a. saturated and liquid at room temperature.
b. unsaturated and liquid at room temperature.
c. saturated and solid at room temperature.
d. unsaturated and solid at room temperature.
____ 11. The diagram above displays six different amino acids (1-6). Which R groups are considered to be
both hydrophobic and nonpolar?
a. 1 and 3
c. 3 and 6
b. 2 and 4
d. 4 and 2
____ 12. Which of the following statements best summarizes the structural differences between DNA and
RNA?
a. RNA is a protein, whereas DNA is a nucleic acid.
b. DNA is a protein, whereas RNA is a nucleic acid.
c. DNA nucleotides contain a different sugar than RNA nucleotides.
d. RNA is a double helix, but DNA is single-stranded.
____ 13.
What
[this region is outside the cell]
The bilayer structure in the left figure represents a
portion of a cell membrane and is composed of
a. structural proteins.
b. polysaccharides.
c. triacylglycerols (triglycerides).
d. phospholipids.
[this region is inside the cell]
____ 14. The bilayer structure in the above figure is maintained because
a. of hydrogen bonding between the tails.
b. of van der Waals forces between the heads.
c. the tails are nonpolar and the heads are polar.
d. the tails are hydrophilic and the heads are hydrophobic.
____ 15. Which of the following are storage polysaccharides?
a. cellulose and chitin
c. cholesterol and triacyglycerol
b. glucose and sucrose
d. glycogen and starch
____ 16.
Which arrow within the cartoon
on the right is pointing towards
van der Waals forces?
a. A
b. B
c. C
d. D
____ 17. Humans can digest starch but not cellulose because
a. the monomer of starch is glucose, while the monomer of cellulose is galactose.
b. humans have enzymes that can hydrolyze the ester linkages of starch but not the
phosphodiester linkages of cellulose.
c. humans have enzymes that can hydrolyze the alpha () glycosidic linkages of
starch but not the beta () glycosidic linkages of cellulose.
d. humans harbor starch-digesting bacteria in the digestive tract.
____ 18. What is the type of bond that forms between monomers thereby joining them into polymers?
a. hydrogen
b. ionic
c. covalent
d. peptide
____ 19. Which of the following best describes the flow of information in eukaryotic cells?
a.
b.
c.
d.
____ 20.
The structure displayed in the picture on the right shows the
a. 1-4 linkage of the  glucose monomers of starch.
b. 1-4 linkage of the  glucose monomers of cellulose.
c. double helical structure of a DNA molecule.
d.  helix secondary structure of a polypeptide.
____ 21. All lipids
a. are made from glycerol and fatty acids. c. are polymers.
b. contain nitrogen.
d. do not dissolve well in water.
____ 22. In the structural formula above the peptide bond is labeled
a. A
c. C
b. B
d. D
____ 23. What happens to the shape and function of a protein if one of the amino acids is replaced with a
different type of amino acid?
a. The protein's quaternary structure will be damaged.
b. The protein will not change; several amino acids must be altered to have any effect
on protein function.
c. The protein will always denature and become entirely nonfunctional.
d. Depending on the chemical nature of the amino acid the protein may lose its
function or there may be no measurable effect on the protein’s function.
____ 24. Which protein is mismatched to its function?
a. antibody - protection for invading microoganisms
b. keratin - structural support, ex. hair
c. enzymes - transport oxygen
d. actin and myosin - muscle contraction
____ 25. A new organism is discovered in Indonesia. Scientists there determine that the polypeptide
sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65
differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data
suggest that the new organism
a. is more closely related to humans than to frogs.
b. is more closely related to humans than to rats.
c. may have evolved from gibbons but not rats.
d. is more closely related to frogs than to humans.
____ 26. At a cooking demonstration, the speaker’s grand finale was sautéing mealworm (insect larvae) in
butter and serving them to the audience. They were crunchy (like popcorn hulls) because their
exoskeletons contain the polysaccharide
a. collagen
c. cellulose
b. chitin
d. glycogen
____ 27. There are 20 different amino acids. What makes one amino acid different from another?
a. different carboxyl groups attached to an alpha () carbon
b. different amino groups attached to an alpha () carbon
c. different side chains (R groups) attached to an alpha () carbon
d. different alpha () carbons
____ 28. Lactose, a sugar in milk, is composed of a glucose molecule bonded to a galactose molecule.
How is lactose classified?
a. as a pentose
b. as a monosaccharide
c. as a disaccharide
d. as a polysaccharide
1. An AP Biology student was assigned the task of preparing a salt solution for her lab group to use
in the Diffusion and Osmosis Lab. Two liters (2 L) of 0.5 M NaCl was required. The molar mass
of sodium equals 23g and the molar mass of chlorine equals 35.5g.
How many grams of table salt will be needed to prepare this solution? (2 pts)
2a. The figure below represents the configuration of carbon and hydrogen atoms in a segment of a
fatty acid chain. Describe the resulting shape of the fatty acid chain and draw a solid line in the
appropriate shape to model your description. Provide an explanation as to the shape of your line
model. (2 pts)
2b. Provide a summary that links the shape of fatty acid chains to the density and melting point of
the triglycerides in which they are incorporated. (2 pts)
(A)
(B)
(C)
(D)
The drawings above illustrate monomers or polymers of the 4 types of macromolecules found in
cells.
1a. Identify the category of organic molecules to which your choice of TWO of the four
molecule above belongs and describe how you identified the molecule. (3 pts)
1b. Discuss the biological importance of your two chosen organic compounds in relation to
cellular structure and/or function. (3 pts)
ANSWER SHEET – Big Idea 2 Exam on The Chemical Context of Life, Water, Carbon and
Macromolecules
Name: _________________________________
Date: __________________
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Part B
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