Life and Chemistry: Large Molecules
3
Life and Chemistry: Large Molecules
TEST FILE QUESTIONS
Fill in the Blank
1.. Fluidity and melting point of fatty acids are partially determined by the number of ______bonds.
2. Many monosaccharides like fructose, mannose, and galactose have the same chemical formula as glucose (C6H12O6), but the atoms are combined differently to yield different structural arrangements. These varying forms of the same chemical formula are called ______.
3. The highly branched polysaccharide that stores glucose in the muscle and the liver of animals is ______.
4. In proteins, amino acids are linked together by ______bonds.
5. The only amino acid that has no stereoisomer is ______.
6. The amino acid that most limits rotation around the a carbon is ______.
7. The bonds between the units in a carbohydrate polymer are called ______bonds.
8. The linear arrangement of amino acids in the polypeptide chain is referred to as the ______structure of the protein.
9. Starch is a polymer of glucose subunits. The subunits of any polymer are called ______.
10. Fatty acids with more than one carbon–carbon double bond are called ______.
11. Cholesterol, vitamin D, and testosterone all have a multiple-ring structure and are members of a family of lipids known as ______.
12. Carbohydrates made up of two simple sugars are called ______.
13. The covalent bond forces between the sulfur atoms of two cysteine side chains is called a ______.
14. Disulfide bonds can form between ______residues in proteins.
15. All amino acids have a hydrogen atom, a carboxyl group, and an amino group attached to a carbon atom. The variability in the 20 different amino acids lies in the structure of their ______.
16. A(n) ______linkage connects the fatty acid molecule to glycerol.
17. The ______molecules found in humans are the same as those found in tomato plants.
18. The bonds that link sugar monomers together in a starch molecule are ______bonds.
19. Cholesterol is classified as a(n) ______.
20. The reaction A — H + B — OH → A — B + H2O represents a ______.
Multiple Choice
1. The major classes of biologically significant large molecules include all of the following except
a. proteins.
b. nucleic acids.
c. carbohydrates.
d. lipids.
e. triglycerides.
2. Lipids are
a. insoluble in water.
b. readily soluble in organic solvents.
c. characterized by their solubility.
d. important constituents of biological membranes.
e. All of the above
3. Which of the following is characteristic of proteins?
a. They are insoluble in water.
b. They are the structural units of glycogen.
c. They possess glycosidic linkages between amino acids.
d. Some function as enzymes.
e. a, b, and c
4. Molecules with molecular weights greater than 1,000 daltons are usually called
a. proteins.
b. polymers.
c. nucleic acids.
d. macromolecules.
e. monomers.
5. In condensation reactions, the atoms that make up a water molecule are derived from
a. oxygen.
b. only one of the reactants.
c. both of the reactants.
d. carbohydrates.
e. enzymes.
6. Which of the following is not a characteristic of lipids?
a. They are readily soluble in water.
b. They are soluble in organic solvents.
c. They release large amounts of energy when broken down.
d. They form two layers when mixed with water.
e. They act as an energy storehouse.
7. Cholesterol is soluble in ether, an organic solvent, but it is not soluble in water. Based on this information, what class of biological macromolecules does cholesterol belong to?
a. Nucleic acids
b. Carbohydrates
c. Proteins
d. Enzymes
e. Lipids
8. Which of the following is not a function in which lipids play an important role?
a. Vision
b. Storing energy
c. Membrane structure
d. Storing genetic information
e. Chemical signaling
9. In a biological membrane, the phospholipids are arranged with the fatty acid chains facing the interior of the membrane. As a result, the interior of the membrane is
a. hydrophobic.
b. hydrophilic.
c. charged.
d. polar.
e. filled with water.
10. The monomers that make up polymeric carbohydrates like starch are called
a. nucleotides.
b. trisaccharides.
c. monosaccharides.
d. nucleosides.
e. fatty acids.
11. The atoms that make up carbohydrates are
a. C, H, and N.
b. C and H.
c. C, H, and P.
d. C, H, and O.
e. C, H, O, and N.
12. Glucose and fructose both have the formula C6H12O6, but the atoms in these two compounds are arranged differently. Glucose and fructose are known as
a. isomers.
b. polysaccharides.
c. oligosaccharides.
d. pentoses.
e. steroids.
13. A nucleotide contains a pentose, a phosphate, and a(n)
a. lipid.
b. acid.
c. nitrogen-containing base.
d. amino acid.
e. glycerol.
14. Two important polysaccharides made up of glucose monomers are
a. guanine and cytosine.
b. RNA and DNA.
c. sucrose and lactose.
d. cellulose and starch.
e. testosterone and cortisone.
15. Polysaccharides that serve as energy storage molecules tend to have ______linkages.
a. a-1,4
b. a-2,3
c. b-1,4
d. b-2,3
e. Both a and c
16. Cellulose is the most abundant organic compound on Earth. Its main function is
a. to store genetic information.
b. as a storage compound for energy in plant cells.
c. as a storage compound for energy in animal cells.
d. as a component of biological membranes.
e. to provide mechanical strength to plant cell walls.
17. In animals, glucose is stored in the compound
a. cellulose.
b. amylose.
c. glycogen.
d. fructose.
e. cellobiose.
18. Which of the following monomer/polymer pairs is not correct?
a. Monosaccharide/polysaccharide
b. Amino acid/protein
c. Triglyceride/lipid
d. Nucleotide/DNA
e. Nucleotide/RNA
19. The side chain of leucine is a hydrocarbon. In a folded protein, where would you expect to find leucine?
a. In the interior of a cytoplasmic enzyme
b. On the exterior of a protein embedded in a membrane
c. On the exterior of a cytoplasmic enzyme
d. Both a and b
e. Both a and c
20. What is the theoretical number of different proteins that you could make from 50 amino acids?
a. 5020
b. 2050
c. 2050
d. 1050
e. 250
21. DNA molecules that carry different genetic information can be distinguished by looking at
a. the number of strands in the helix.
b. how much uracil is present.
c. the sequence of nucleotide bases.
d. differences in the base-pairing rules.
e. the shape of the helix.
22. The “backbone” of nucleic acid molecules is made of
a. nitrogenous bases.
b. alternating sugars and phosphate groups.
c. purines.
d. pyrimidines.
e. nucleosides.
23. According to the base-pairing rules for nucleic acids, purines always pair with
a. deoxyribose sugars.
b. uracil.
c. pyrimidines.
d. adenine.
e. guanine.
24. What type of amino acid side chains would you expect to find on the surface of a protein embedded in a cell membrane?
a. Cysteine
b. Hydrophobic
c. Hydrophilic
d. Charged
e. Polar, but not charged
25. A molecule with the formula C16H32O2 is a
a. hydrocarbon.
b. carbohydrate.
c. lipid.
d. protein.
e. nucleic acid.
26. A molecule with the formula C16H30O15 is a
a. hydrocarbon.
b. carbohydrate.
c. lipid.
d. protein.
e. nucleic acid.
27. Fatty acids are molecules that
a. contain fats bonded to a glycerol.
b. are composed of hydrogen, carbon, and a carboxyl group.
c. are carbohydrates linked to a hydrocarbon chain.
d. contain glycerol and a carboxyl group.
e. are always saturated.
28. Sucrose is a
a. hexose.
b. lipid.
c. disaccharide.
d. glucose.
e. simple sugar.
29. DNA and RNA contain
a. pentoses.
b. hexoses.
c. fructoses.
d. maltoses.
e. amyloses.
30. The 20 different common amino acids have different
a. amino groups.
b. R groups.
c. acid groups.
d. peptide linkages.
e. primary structures.
31. The primary structure of a protein is determined by its
a. disulfide bridges.
b. a helix structure.
c. sequence of amino acids.
d. branching.
e. three-dimensional structure.
32. A protein can best be defined as a polymer
a. of amino acids.
b. containing one or more polypeptide chains.
c. containing 20 amino acids.
d. containing 20 peptide linkages.
e. containing double helices.
33. The four nitrogenous bases of RNA are abbreviated as
a. A, G, C, and T.
b. A, G, T, and N.
c. G, C, U, and N.
d. A, G, U, and T.
e. A, G, C, and U.
34. DNA carries genetic information in its
a. helical form.
b. sequence of bases.
c. tertiary sequence.
d. sequence of amino acids.
e. phosphate groups.
35. A molecule often spoken of as having a head and tail is a(n)
a. phospholipid.
b. oligosaccharide.
c. RNA.
d. steroid.
e. triglyceride.
36. A molecule that has an important role in limiting what gets into and out of cells is
a. glucose.
b. maltose.
c. phospholipid.
d. fat.
e. phosphohexose.
37. A molecule that has an important role in long-term storage of energy is
a. a steroid.
b. RNA.
c. glycogen.
d. an amino acid.
e. hexose.
38. A peptide linkage (peptide bond) holds together two ______molecules.
a. protein
b. amino acid
c. sugar
d. fatty acid
e. phospholipid
39. In DNA molecules,
a. purines pair with pyrimidines.
b. A pairs with C.
c. G pairs with A.
d. purines pair with purines.
e. C pairs with T.
40. A type of molecule very often drawn with a single six-sided ring structure is
a. sucrose.
b. an amino acid.
c. glucose.
d. a fatty acid.
e. a steroid.
41. Maltose and lactose are similar in that they both are
a. simple sugars.
b. amino acids.
c. insoluble in water.
d. disaccharides.
e. hexoses.
42. Starch and glycogen are different in that only one of them
a. is a polymer of glucose.
b. contains ribose.
c. is made in plants.
d. is an energy storage molecule.
e. can be digested by humans.
43. Enzymes are
a. DNA.
b. lipids.
c. carbohydrates.
d. proteins.
e. amino acids.
44. The type of bond that holds two amino acids together in a polypeptide chain is a(n)
a. ionic bond.
b. disulfide bridge.
c. hydrogen bond.
d. peptide linkage.
e. dehydration bond.
45. Peptides have ______and ______end.
a. a start; a stop
b. a +; a –
c. an N terminus; a C terminus
d. a 5’; a 3’
e. an A; a Z
46. The ______structure of a protein concerns the way separate polypeptides are assembled together.
a. primary
b. secondary
c. tertiary
d. quaternary
e. helical
47. Quaternary structure is found in proteins
a. composed of subunits.
b. of membranes.
c. of the quadruple complex.
d. that change over time.
e. None of the above
48. In DNA, A hydrogen bonds with T and G with C; these are examples of a specific type of reaction called
a. complementary base pairing.
b. a dehydration reaction.
c. a reduction reaction.
d. a hydrophobic reaction.
e. a purine–purine reaction.
49. A fat contains fatty acids and
a. glycerol.
b. a base.
c. an amino acid.
d. a phosphate.
e. None of the above
50. There are ______different types of tripeptides (molecules with three amino acids linked together) that can exist using the 20 common amino acids.
a. 3
b. 20
c. 60
d. 900
e. 8,000
51. Chitin is a polymer of
a. galactosamine.
b. glucose.
c. glucosamine.
d. glycine.
e. All of the above
52. A type of protein that functions by helping other proteins to fold correctly is called
a. foldzyme.
b. renaturing protein.
c. chaperonin.
d. hemoglobin.
e. denaturing protein.
53. The composition of a protein is
a. its three-dimensional structure.
b. the number and kinds of amino acids present.
c. the particular side chain or R group present.
d. similar in every protein because every protein contains 20 different amino acids.
e. universal because all proteins have an equal number of amino acids.
54. Why does bread become hard and stale?
a. Cellulose molecules aggregate in the absence of water.
b. In the absence of water, unbranched starch forms hydrogen bonds between polysaccharides, which then aggregate.
c. The release of carbon dioxide causes the bread to harden.
d. Water and heat cause the polysaccharide chains to bind together.
e. Mold growth interferes with a linkages, causing the bread to harden.
55. The difference between α- and β- glucose is
a. in the number of covalent bonds present.
b. in the placement of OH and H atoms.
c. in the type of R group attached to the terminal carbon.
d. that a-glucose is polar, whereas b-glucose is nonpolar.
e. that a-glucose is a pentose, whereas b-glucose is a hexose.
56. Examination of meterorites has revealed that they contain the chemistry of life. All of the following have been found except
a. purines and pyrimidines.
b. amino acids.
c. glucose.
d. magnetite.
e. polycyclic aromatic hydrocarbons.
57. Examination of meteorites suggests that
a. life is not limited to Earth.
b. life originated in outer space from nonliving matter.
c. comets brought Earth most of its water.
d. meteorites brought life to Earth.
e. they are responsible for the Earth’s magnetic field.
58. Earth’s early atmosphere contained all of the following gases except
a. carbon dioxide.
b. sulfur dioxide.
c. hydrogen sulfide.
d. oxygen.
e. methane.
59. Incorrect folding of a protein can have serious consequences. For instance, an accumulation of misfolded proteins in the brain is a characteristic of
a. rickets.
b. Alzheimer’s disease.
c. hemophilia.
d. excessively dry skin.
e. night blindness.
60. It is important to know the exact shape of a protein because the knowledge allows scientists to
a. create specific proteins to block the action of another protein.
b. create multi-protein machines to synthesize RNA.
c. synthesize antibodies that kill viruses.
d. predict whether the protein will form an a or b chain.
e. predict the energy required to break the protein’s bonds.
61. The double helix structure of DNA is due to
a. complementary base pairings.
b. purines bonding with pyrimidines.
c. the phosphodiester bonds between deoxyribose and phosphate.
d. hydrogen bonding of the two complementary polynucleotide strands.
e. ionic bonding of base pairs.
62. Spontaneous generation was disproved by
a. Miller.
b. Urey.
c. Redi and Pasteur.
d. Allan Hills.
e. van der Waal.
63. RNA molecules that act as catalysts are called
a. ribozymes.
b. proteases.
c. chaperonins.
d. disulfide bridges.
e. triglycerides.