Chapter 2 Bio
A proteome is: A Option A: an inventory of all of the proteins in a tissue, cell, or cellular organelle. B Option B: all of the mRNA in a cell. C Option C: the cell's rDNA. D Option D: another name for a genome.
A
Fats that remain solid at room temperature are MOST likely to be: A Option A: saturated. B Option B: unsaturated. C Option C: polyunsaturated. D Option D: none of the choices is correct.
A
Water has extraordinary properties to support life such as the capacity to: A Option A: form hydrogen bonds with up to four other water molecules. B Option B: evaporate easily at relatively low temperatures. C Option C: dissolve a very limited number of substances. D Option D: prevent forming interactions with many other chemicals.
A
Which amino acid is MOST likely to be found in the core of a protein? A Option A: methionine B Option B: asparagine C Option C: serine D Option D: threonine E Option E: glutamic acid
A
Why are free ionic bonds of little importance and relatively unlikely to form in living organisms? 1)Cells are composed mostly of water, which interferes with ionic bonds between free ions. 2)Cells are largely hydrophobic. 3)They are crystals. A Option A: 1 B Option B: 2 C Option C: 3 D Option D: 1 and 2 E Option E: 2 and 3
A
A release of hydrogen ions to a solution would MOST likely ____________. A Option A: raise pH B Option B: lower pH C Option C: buffer pH D Option D: change salinity E Option E: keep pH steady
B
All of the following are parts of a nucleotide EXCEPT: A Option A: a five-carbon sugar. B Option B: a six-carbon sugar. C Option C: a phosphate group. D Option D: a nitrogenous base.
B
How do amino acids like hydroxylysine and thyroxine, which are NOT among the 20 amino acids that are inserted into proteins, get into proteins? A Option A: They are inserted directly. B Option B: They are the result of the alteration of R groups of the 20 amino acids after their incorporation into the polypeptide. C Option C: They are the result of the alteration of R groups of the 20 amino acids before their incorporation into the polypeptide. D Option D: There are more than the 20 amino acids that are said to be inserted into proteins. E Option E: Their atoms are altered by insertion into the polypeptide.
B
The primary structure of a polypeptide is: A Option A: the DNA sequence that encodes the protein. B Option B: the specific linear sequence of amino acids that constitutes the polypeptide chain. C Option C: the nucleotide sequence of the tryptophan tRNA. D Option D: the three-dimensional structure of the protein.
B
The β -pleated sheet is characterized by orientation of ______ the molecular axis. A Option A: H bonds parallel to B Option B: H bonds perpendicular to C Option C: ionic bonds parallel to D Option D: ionic bonds perpendicular to E Option E: peptide bonds perpendicular to
B
Water is sometimes called the 21st amino acid because of its importance in defining protein structure. The basis for this is the so-called hydrophobic effect. Which of the following BEST describes the hydrophobic effect? A Option A: Polar regions of the protein are repelled by water, driving them to the interior of the protein. B Option B: Non-polar regions of the protein are repelled by water, driving them to the interior of the molecule. C Option C: Water and the protein arrange themselves so that the nonpolar surface in contact with water is maximized. D Option D: All of the choices are correct.
B
What kind of bond results from an unequal sharing of electrons? A Option A: ionic bond B Option B: polar covalent bond C Option C: H bond D Option D: nonpolar covalent bond
B
Where are hydrophobic interactions MOST likely to occur? A Option A: on the surface of a water-soluble protein B Option B: the core of a water-soluble protein C Option C: in contact with water molecules D Option D: between two charged molecules E Option E: between two ions
B
Which of the following is NOT a macromolecule formed by polymerization? A Option A: proteins B Option B: lipids C Option C: polynucleotides D Option D: polysaccharides E Option E: DNA
B
Which of the following is NOT found in DNA? A Option A: adenine B Option B: uracil C Option C: cytosine D Option D: thymine
B
Which polysaccharide bond CANNOT be broken by mammalian enzymes that normally digest polysaccharides? A Option A: α (1—>4) glycosidic linkages B Option B: β (1—>4) glycosidic linkages C Option C: α (1—>6) glycosidic linkages D Option D: β (1—>6) glycosidic linkages E Option E: phosphate ester linkages
B
Why do sugars tend to be highly water soluble? A Option A: because they have only a few hydroxyl groups B Option B: because of their large numbers of hydroxyl groups C Option C: because of their large numbers of sulfhydryl groups D Option D: because of their large numbers of methyl groups E Option E: because of their small molecular weights
B
A molecule that is capable of releasing or donating a hydrogen ion is termed a(n) _______. A Option A: base B Option B: hydrion C Option C: acid D Option D: anachronism E Option E: pain
C
Amino acids are to proteins as __________ are to carbohydrates. A Option A: fatty acids B Option B: nucleic acids C Option C: monosaccharides D Option D: nucleotides
C
In a living organism, where are ionic bonds MOST likely to be found? A Option A: in the cytoplasm B Option B: between DNA strands C Option C: deep in a protein's core where water is excluded D Option D: on the surface of a protein E Option E: on the surface of a lipid
C
Proteins are often composed of two or more distinct modules that fold up independently of one another. They often represent parts of a protein that function in a semi-independent manner. These modules are called ______. A Option A: protein motifs B Option B: functionals C Option C: domains D Option D: dominoes
C
Scientists can produce novel proteins by modifying existing proteins using: A Option A: modular construction. B Option B: affinity-related targeting. C Option C: site-directed mutagenesis. D Option D: the yeast two-hybrid system.
C
Tertiary structure can be determined using: A Option A: X-ray crystallography. B Option B: nuclear magnetic resonance spectroscopy. C Option C: both X-ray crystallography and nuclear magnetic resonance spectroscopy. D Option D: thin layer chromatography.
C
The infectious agent for Creutzfeld-Jakob disease is a ________ A Option A: virus B Option B: bacterium C Option C: protein D Option D: fungus
C
The low-molecular-weight building blocks of polymers are called _______. A Option A: minipolymers B Option B: monoblocks C Option C: monomers D Option D: portions E Option E: octamers
C
Under which circumstances would electrons be MOST likely to be shared equally? A Option A: when they are equidistant from nuclei B Option B: when they are equidistant from each other C Option C: when atoms of the same element are sharing them D Option D: when the atoms sharing them are different
C
What is the consequence of placing a proline side chain within an alpha helix? A Option A: Proline stabilizes the folded alpha helical structure, causing it to kink. B Option B: Proline isomerizes to the trans form and the alpha helix is undisturbed. C Option C: Proline disrupts the structure of an alpha helix, causing it to kink. D Option D: All of the choices are correct.
C
What is the maximum number of 100 amino acid long polypeptides that could be made? A Option A: 10020 B Option B: 2,000 C Option C: 20^100 D Option D: 20101 E Option E: 20
C
What type of protein secondary structure is characterized as being highly extensible because of its coiled structure? A Option A: β -pleated sheet B Option B: double helix C Option C: α -helix D Option D: supercoiling
C
Which interaction is MOST important in enhancing the solubility of macromolecules in water? A Option A: hydrophobic interactions B Option B: nonpolar covalent bonds C Option C: H bonds D Option D: van der Waals forces E Option E: both hydrophobic interactions and nonpolar covalent bonds
C
Which of the following is NOT a structural polysaccharide? A Option A: chitin B Option B: cellulose C Option C: glycogen D Option D: glycosaminoglycan
C
Amino acids: A Option A: can form peptide bonds. B Option B: are composed of a central carbon surrounded by an amino group, a carboxyl group, a hydrogen atom and a variable side chain. C Option C: can have side chains that are polar, nonpolar, or with unique properties. D Option D: all of these statements are true.
D
Some of the functions of proteins include: A Option A: regulation. B Option B: antibodies. C Option C: growth factors. D Option D: all of the choices are correct.
D
The MOST stable atoms and thus those that are typically nonreactive are the atoms that have _______. A Option A: equal numbers of electrons and protons B Option B: equal numbers of electrons and neutrons C Option C: full inner shells D Option D: full outer shells E Option E: all covalent bonds
D
The chloride ion has an extra electron relative to the number of protons in its nucleus. Thus, chloride: A Option A: has a negative charge. B Option B: has lost an electron. C Option C: can bind a cation. D Option D: has a negative charge and can bind a cation.
D
The normal blood pH is about 7.4. What is the concentration of the hydrogen ion? A Option A: 6.6 M B Option B: 7.0 M C Option C: 7.4 M D Option D: None of the choices is correct.
D
The term "conformation" refers to: A Option A: the three-dimensional arrangement of the atoms of a molecule. B Option B: the spatial organization of atoms in a molecule. C Option C: the amino acid sequence of a polypeptide. D Option D: both the three-dimensional arrangement of the atoms of a molecule and the spatial organization of atoms in a molecule.
D
What level of structure in proteins is held together by intermolecular R group interactions? A Option A: primary structure B Option B: secondary structure C Option C: tertiary structure D Option D: quaternary structure
D
Which of the following is a nucleotide? A Option A: phosphate + ribose B Option B: adenine + deoxyribose C Option C: sugar + nitrogenous base D Option D: adenine + ribose + phosphate
D
Which of the following statements about phospholipids is TRUE? A Option A: Each one has three fatty acid chains. B Option B: The glycerol backbone is bonded to a small nonpolar group. C Option C: Their biological function remains unknown. D Option D: Each one has two fatty acid chains and the glycerol backbone is bonded to a small polar group.
D
Which of the following structures of proteins is composed of two or more polypeptide chains? A Option A: Primary B Option B: Secondary C Option C: Tertiary D Option D: Quaternary
D
help(s) unfolded or misfolded proteins achieve their proper three-dimensional conformation. A Option A: Ribosomes B Option B: Endoplasmic reticulum C Option C: Ribonuclease D Option D: Molecular chaperones
D
What kind of noncovalent interaction is typified by interactions between two molecules that are so close together that they can experience weak attractive forces bonding them together? A Option A: H bonds B Option B: ionic bonds C Option C: hydrophobic interactions D Option D: polar covalent bonds E Option E: van der Waals forces
E
