Bio Chapter 5 Exam
If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence
5'TGCAAT3'
At which level of protein structure are interactions between the side chains (R groups) most important?
tertiary
If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
40
All of the following contain amino acids except
cholesterol.
The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA
contains one less oxygen atom.
Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?
5'-ATGC-3' with 5'-GCAT-3'
If cells are grown in a medium containing radioactive ¹⁵N, which of these molecules will be labeled?
both proteins and nucleic acids
What is the structural feature that allows DNA to replicate?
complementary pairing of the nitrogenous bases
What is the term used for a protein molecule that assists in the proper folding of other proteins?
chaperonin
Which of the following polymers contain nitrogen?
chitin
The structural level of a protein least affected by a disruption in hydrogen bonding is the
primary level.
A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of
120 thymine and 120 adenine molecules.
How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long
10
How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?
20¹²
Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein?
99
Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?
Alzheimer's and Parkinson's only
The molecular formula for glucose is C₆H₁2O₆. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?
C₁₈H₃₂O₁₆
The molecular formula for glucose is C₆H₁₂O₆. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?
C₆₀H₁₀₂O₅₁
Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides. Among these biological polymers, which has the least structural variety
DNA
How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?
DNA duplexes will unwind and separate, and proteins will unfold (denature).
Which of the following statements best summarizes the differences between DNA and RNA?
DNA nucleotides contain a different sugar than RNA nucleotides.
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
Which of the following is true of cellulose?
It is a major structural component of plant cell walls
If ¹⁴C-labeled uridine triphosphate is added to the growth medium of cells, what macromolecules will be labeled?
RNA
The R group or side chain of the amino acid serine is -CH₂-OH. The R group or side chain of the amino acid leucine is -CH₂-CH-(CH₃)₂. Where would you expect to find these amino acids in a globular protein in aqueous solution?
Leucine would be in the interior, and serine would be on the exterior of the globular protein.
Which of the following statements about the 5' end of a polynucleotide strand of DNA is correct?
The 5' end has a phosphate group attached to the number 5 carbon of ribose.
The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to vegetable oil?
The hydrogenated vegetable oil stays solid at room temperature.
DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?
The phosphodiester bonds between deoxyribose sugars would be broken.
Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?
The phosphodiester linkages of the polynucleotide backbone would be broken.
of the following is true of both starch and cellulose?
They are both polymers of glucose.
Which of the following statements is true for the class of biological molecules known as lipids?
They are insoluble in water.
Why are human sex hormones considered to be lipids?
They are not soluble in water.
Which of the following is true regarding saturated fatty acids?
They are the principal molecules in lard and butter.
Which of the following statements concerning unsaturated fats is true?
They have double bonds in the carbon chains of their fatty acids.
Which of the following statements concerning saturated fats is not true?
They have multiple double bonds in the carbon chains of their fatty acids.
Which of the following descriptions best fits the class of molecules known as nucleotides?
a nitrogenous base, a phosphate group, and a pentose sugar
Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement?
a steroid
Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures?
adding hydrogens and trans double bonds to the fatty acids
Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two molecules of α hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits
altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.
Changing a single amino acid in a protein consisting of 325 amino acids would
always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and affect its biological activity.
Polysaccharides, triacylglycerides, and proteins are similar in that they
are synthesized from subunits by dehydration reactions.
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?
as a disaccharide
of the following techniques uses the amino acid sequences of polypeptides to predict a protein's three-dimensional structure?
bioinformatics
What methods may be used to elucidate the structures of purified proteins?
both X-ray crystallography and NMR spectroscopy
If cells are grown in a medium containing radioactive ³²P-labeled phosphate, which of these molecules will be labeled?
both phospholipids and nucleic acids
A molecule with the chemical formula C₆H₁₂O₆ is probably a
carbohydrate and monosaccharide only.
Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?
carbohydrates
On food packages, to what does the term insoluble fiber refer?
cellulose
Which of the following are nitrogenous bases of the pyrimidine type?
cytosine and uracil
What is the chemical reaction mechanism by which cells make polymers from monomers?
dehydration reactions
There are 20 different amino acids. What makes one amino acid different from another?
different side chains (R groups) attached to an α carbon
What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptide's specific three-dimensional shape?
disulfide bond
Molecules with which functional groups may form polymers via dehydration reactions?
either hydroxyl or carboxyl groups
A molecule with the formula C₁₈H3₆O₂ is probably a
fatty acid.
Which of these molecules is not formed by dehydration reactions?
fatty acids
One of the primary functions of RNA molecules is to
function in the synthesis of proteins.
Which of the following is not a polymer
glucose
The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?
glycogen
The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the α form. Which of the following could amylase break down?
glycogen, starch, and amylopectin
Which of the following are nitrogenous bases of the purine type?
guanine and adenine
Humans can digest starch but not cellulose because
humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.
Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?
hydrogen bonds
What maintains the secondary structure of a protein?
hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
The amino acids of the protein keratin are arranged predominantly in an α helix. This secondary structure is stabilized by
hydrogen bonds.
In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?
in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains
A new organism is discovered in the forests of Costa Rica. 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
is more closely related to frogs than to humans.
All of the following are polysaccharides except
lactose.
Which bonds are created during the formation of the primary structure of a protein?
peptide bonds
Professor Jamey Marth at the University of California, Santa Barbara, identified 70 molecules that are used to build cellular macromolecules and structures. These include at least 34 saccharides, 8 nucleosides, and 20 amino acids. In theory, then, which class of biological polymer has the greatest information-coding capacity?
polysaccharides
If cells are grown in a medium containing radioactive ³⁵S, which of these molecules will be labeled?
proteins
Which class of biological polymer has the greatest functional variety?
proteins
The bonding of two amino acid molecules to form a larger molecule requires which of the following?
removal of a water molecule
Which level of protein structure do the α helix and the β pleated sheet represent?
secondary
What aspects of protein structure are stabilized or assisted by hydrogen bonds?
secondary, tertiary, and quaternary structures, but not primary structure
Which of the following is an example of hydrolysis?
the reaction of a fat, forming glycerol and fatty acids with the consumption of water
The bonding of two amino acid molecules to form a larger molecule requires
the release of a water molecule.
Humans and mice differ because
their cells have some differences in the sequence of nucleotides in their nucleic acids.
Dehydration reactions are used in forming which of the following compounds?
triacylglycerides, polysaccharides, and proteins
Which of the following is not a monomer/polymer pairing?
triglyceride/phospholipid bilayer
The tertiary structure of a protein is the
unique three-dimensional shape of the fully folded polypeptide.
In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy. Only a small portion of these monomers are used for synthesis of new macromolecules. The net result is that
water is consumed by animal metabolism.
