exam review questions Flashcards
A molecule with the formula C18H36O2 is probably a
Fatty acid
) Which of the following statements regarding lipids is true?
A) They generally contain nitrogen.
B) They are made from glycerol and amino acids.
C) A gram of lipid stores less energy than a gram of carbohydrate.
D) They are insoluble in water
They are insouble in water
Hydrogenated vegetable oil is the primary ingredient in margarine. How does hydrogenated vegetable oil differ from nonhydrogenated vegetable oil?
A) Hydrogenated vegetable oil has a lower melting point than nonhydrogenated vegetable oil.
B) Hydrogenated vegetable oil is solid at room temperature, whereas nonhydrogenated vegetable oil is liquid.
C) Hydrogenated vegetable oil has more kinks in its fatty acid chains than does nonhydrogenated vegetable oil.
D) Hydrogenated vegetable oil contains more cis fatty acids than nonhydrogenated vegetable oil
B
Which of the following statements regarding saturated fatty acids is true?
A) They are the predominant fatty acid in corn oil.
B) They have double bonds between the carbon atoms of the fatty acids.
C) They are the principal molecules in lard and butter.
D) They are usually liquid at room temperature.
E) They are usually produced by plants.
C
Large organic molecules are generally synthesized by polymerization of a few types of simple subunits. Which of the following is an exception to this statement?
A) a steroid
B) cellulose
C) DNA
D) an enzyme
steroid
Which of the following large biological molecules will self-assemble into a bilayer when mixed with water?
A) proteins
B) triacylglycerols
C) cellulose
D) phospholipids
Phospholipid
Why are the vertebrate sex hormones estradiol and testosterone considered to be lipids?
A) They are essential components of cell membranes.
B) Their carbon skeletons are composed of primarily C–C and C–H bonds.
C) They are made of fatty acids.
D) They are hydrophilic compounds.
their carbon skeletons are composed of primarily C-C and C-H bonds
Which of the following molecules lacks amino acids?
A) hemoglobin
B) insulin
C) antibodies
D) spider silk
E) cholesterol
Chlolesterol
There are 20 different amino acids. What makes one amino acid different from another?
A) different side chains (R groups) attached to the carboxyl carbon
B) different side chains (R groups) attached to the amino groups
C) different side chains (R groups) attached to an α carbon
D) different asymmetric carbons
Different side chains attached to an α carbon
Which bonds are created during the formation of the primary structure of a protein?
A) disulfide bonds
B) hydrogen bonds
C) peptide bonds
D) phosphodiester bonds
Peptide bonds
Which bonds maintain the primary structure of a protein?
A) disulfide bonds
B) hydrogen bonds
C) ionic bonds
D) peptide bonds
Peptide bonds
What maintains the secondary structure of a protein?
A) peptide bonds between adjacent amino acids
B) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
C) disulfide bonds between the amino group of one peptide bond and the R group of another amino acid
D) hydrogen bonds between the carboxyl group of one peptide bond and the R group of another amino acid
hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?
A) hydrophobic interactions
B) ionic bonds
C) hydrogen bonds
D) peptide bonds
Hydrogen bonds
The α helix and β pleated sheet are examples of which level of protein structure?
A) primary
B) secondary
C) tertiary
D) quaternary
E) primary, secondary, tertiary, and quaternary
Secondary
Lactase is an enzyme composed of a single polypeptide that hydrolyzes the disaccharide lactose to produce monosaccharides. The optimal pH for lactase activity is 6. Transfer of lactase to pH 5 results in a substantial decrease in enzyme activity, likely due to the disruption of
A) only the primary structure of the enzyme.
B) the primary and secondary structure of the enzyme.
C) the secondary and tertiary structure of the enzyme.
D) the secondary, tertiary, and quaternary structure of the enzyme
the secondary and tertiary structure of the enzyme.
Polypetide forms through a heydration reaction
primary and tertiary structures are held together by
Collagen is a protein made of three identical polypeptides composed primarily of α helix structure. The α helix is an example of
A) secondary structure stabilized by covalent bonds.
B) secondary structure stabilized by hydrogen bonds.
C) secondary structure stabilized by ionic bonds.
D) tertiary structure stabilized by covalent bonds.
E) tertiary structure stabilized by hydrogen bonds.
secondary structure stabilized by hydrogen bonds.
The tertiary structure of a polypeptide is the
A) linear sequence of amino acids in a polypeptide.
B) localized region of a polypeptide chain that forms an α helix or β pleated sheet.
C) overall three-dimensional shape of a fully folded polypeptide.
D) overall three-dimensional shape of a protein composed of more than one polypeptide.
overall three-dimensional shape of a fully folded polypeptide.
A disulfide bridge is an example of which type of bond?
A) ionic bond between R groups
B) hydrophobic interaction between R groups
C) hydrogen bond between R groups
D) covalent bond between R groups
D) covalent bond between R groups
Interactions between the side chains (R groups) in a polypeptide are most important in stabilizing which of the following?
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
D) quaternary structure
two polypetide chains in a quatery structure
The side chain (R group) of the amino acid serine is –CH2–OH. The 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?
A) Serine would be on the exterior, and leucine would be in the interior of the globular protein.
B) Serine would be in the interior, and leucine would be on the exterior of the globular protein.
C) Both serine and leucine would be in the interior of the globular protein.
D) Both serine and leucine would be on the exterior of the globular protein.
Serine would be on the exterior, and leucine would be in the interior of the globular protein.
Likes dissolve likes
Changing a single amino acid in a protein consisting of 433 amino acids would
A) always alter the primary structure of the protein but never alter its tertiary structure or function.
B) always alter the primary structure of the protein and sometimes alter its tertiary structure or function.
C) always alter the primary and tertiary structure of the protein but never alter its function.
D) sometimes alter the primary and tertiary structure of the protein but always alter its function.
B) always alter the primary structure of the protein and sometimes alter its tertiary structure or function.
Normal hemoglobin is a tetramer, consisting of two molecules of β-globin and two molecules of α-globin. 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
A) altered primary structure.
B) altered secondary structure.
C) altered tertiary structure.
D) altered quaternary structure.
E) altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.
E) altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.
In a normal cellular protein, where would you expect to find a hydrophilic amino acid such as asparagine?
A) in the interior of the folded protein, away from water
B) on the exterior surface of the protein, interacting with water
C) in the transmembrane portion interacting with lipid fatty acid chains
D) on the exterior surface of the protein, interacting with water, or in a transmembrane portion interacting with lipid fatty acid chains
on the exterior surface of the protein, interacting with water
If cells are grown in a medium containing radioactive 35S, which of these molecules will be radioactively labeled?
A) phospholipids
B) nucleic acids
C) proteins
D) starch
Proteins
If cells are grown in a medium containing radioactive 32P, which of these molecules will be radioactively labeled?
A) triacylglycerols
B) nucleic acids
C) fatty acids
D) starch
nucleic acids
How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?
A) Unsaturated fatty acid tails will become saturated.
B) Proteins will unfold (denature).
C) Starch will hydrolyze into monomeric sugars.
D) Proteins will hydrolyze into amino acids.
Proteins will unfold (denature
Which of the following statements about the 5’ end of a polynucleotide strand of RNA is correct?
A) The 5’ end has a hydroxyl group attached to the number 5 carbon of ribose.
B) The 5’ end has a phosphate group attached to the number 5 carbon of ribose.
C) The 5’ end has phosphate attached to the number 5 carbon of the nitrogenous base.
D) The 5’ end has a nitrogenous base attached to the number 5 carbon of ribose.
The 5’ end has a phosphate group attached to the number 5 carbon of ribose.
One of the primary functions of RNA molecules is to
A) transmit genetic information to offspring.
B) function in the synthesis of proteins.
C) make a copy of itself, thus ensuring genetic continuity.
D) act as a pattern or blueprint to form DNA.
Function in the sythesis of proteins
If 14C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?
A) polysaccharides
B) proteins
C) DNA
D) RNA
E) both DNA and RNA
Both DNA and RNA
A nucleotide is composed of
A) a nitrogenous base and a phosphate group.
B) a nitrogenous base and a pentose sugar.
C) a nitrogenous base, a phosphate group, and a pentose sugar.
D) a nitrogenous base, a phosphate group, a pentose sugar, and an amino acid.
a nitrogenous base, a phosphate group, and a pentose sugar.
Which of the following are pyrimidines?
A) adenine and thymine
B) adenine and guanine
C) cytosine and uracil
D) cytosine and guanine
adenine and guanine
purines
cytosine and thymine, uracil in RNA
