Biology 115 Exam 1: Multiple choice
A scientific theory is just a guess about how the natural world works. True or false.
False
DNA and RNA have the same nitrogenous bases. True or False?
False
1. If a DNA double helix contains 20% T nucleotides, then what is the percentage of A nucleotides? a. 20 b. 30 c. 40 d. 50 e. It is impossible to tell from the information given
a. 20
1. If one strand of a DNA molecule has the sequence bases 5' GCAATT 3', the other complementary strand would have the sequence ______. a. 3' CGTTAA 5' b. 5' CGTTAA 3' c. 3' GCAATT 5' d. 5' GCAATT 3' e. 3' TACCGG 5'
a. 3' CGTTAA 5'
1. When nucleotides polymerize to form a nucleic acid _____. a. A covalent bond forms between the sugar of one nucleotide and the phosphate of a second b. A hydrogen bond forms between the sugar of one nucleotide and the phosphate of a second c. Covalent bonds form between the bases of two nucleotides d. Hydrogen bonds form between the bases of two nucleotides
a. A covalent bond forms between the sugar of one nucleotide and the phosphate of a second
Which one of the following is NOT a component of each monomer (amino acid) used to make proteins? a. A phosphorus atom, P b. An amino functional group, NH c. A side chain, R d. A carboxyl group, COOH
a. a phosphorus atom, P
1. Both DNA and RNA _______. a. Are information-containing molecules b. Show primary, secondary, tertiary, and quaternary structure c. Are highly reactive catalysts in cells d. Naturally occur as a double helix
a. are information-containing molecules
1. Compare proteins to nucleic acids. Which of the following is true? a. Both have primary and secondary structure b. Both contain sulfur c. Both take on structural roles in the cell d. Both have monomers, which contain phosphorus.
a. both have primary and secondary structure
1. Simple carbs like glucose are used for 'fuel'.... What kind of fuel? a. Cellular energy through cellular respiration b. Cellular energy through hydrolysis c. Long-term fuel stored in your tissues
a. cellular energy through cellular respiration
1. Which polysaccharide is an important component in the structure of many animals and fungi? a. Chitin b. Cellulose c. Amylopectin d. Amylose
a. chitin
1. What property of water helps get water to the tops of giant redwoods? a. Cohesion b. Specific heat c. Heat of evaporation d. Expansion during freezing e. Universal solvent
a. cohesion
1. What type of chemical bond joins a functional group to the carbon skeleton of a large molecule? a. Covalent bond b. Hydrogen bond c. Ionic bond d. Double bond e. Disulfide bond
a. covalent bond
1. Polymers are made of connected monomer subunits that are joined by what type of bonds? a. Covalent bonds b. Hydrogen bonds c. Hydrophobic bonds d. Ionic binds
a. covalent bonds
Nitrogen (N) is more electronegative than hydrogen (H). Which of the following is a correct statement about the atoms in ammonia (NH)? a. Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge. b. Ammonia has an overall positive charge c. Ammonia has an overall negative charge d. The nitrogen atom has a partial positive charge; each hydrogen atom has a partial negative charge e. There are covalent bonds between the hydrogen atoms and polar bonds between each hydrogen atom and the nitrogen atom
a. each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge
1. The membranes of winter wheat are able to remain fluid when it is extremely cold by_______. a. Increasing the percentage of unsaturated phospholipids in the membrane b. Increasing the percentage of cholesterol molecules in the membrane c. Decreasing the number of hydrophobic proteins in the membrane d. Cotransport of glucose and hydrogen e. Using active transport
a. increasing the percentage of unsaturated phospholipids in the membrane
Suppose you discovered a new amino acid. Its R-group contains only hydrogen and carbon atoms. Predict the behavior of this amino acid. a. It is hydrophobic b. It is hydrophilic c. Relative to the amino acids found in organisms, its interactions with water will be intermediate d. Relative to the amino acids found in organisms, its interactions with water will be very high.
a. it is hydrophobic
1. Which of the following is the monomer for a carbohydrate? a. Monosaccharide b. Amino acid c. Nucleotide d. Fatty acid e. None of the above
a. monosaccaride
1. Nucleic acids are polymers made up of which of the following monomers? a. Nucleotides b. Sugars c. Amino acids d. Nitrogenous bases
a. nucleotides
A covalent bond is likely to be polar when __________ a. one of the atoms sharing electrons is more electronegative than the other atom b. the two atoms sharing electrons are equally electronegative c. carbon is one of the two atoms sharing electrons d. one of the atoms has absorbed more energy than the other atom e. the two atoms sharing electrons are the same elements
a. one of the atoms sharing electrons is more electronegative than the other atom
1. You have a membrane with equal amounts of saturated and unsaturated phospholipids. After testing the permeability of this membrane to glucose, you increase the proportion of unsaturated phospholipids in the bilayer. What will happen to the membrane's permeability to glucose? a. Permeability to glucose will increase b. Permeability to glucose will decrease c. Permeability to glucose will stay the same d. You cannot predict the outcome. You simply have to make the measurement
a. permeability to glucose will increase
1. You denature a protein, disrupting all of its hydrogen bonds. What level of structure will be preserved/ retained? a. Primary structure b. Secondary structure c. Tertiary structure d. Quaternary structure
a. primary structure
1. The bonding of two amino acid molecules to form a larger molecule requires the _____. a. Release of a water molecule b. Release of a carbon dioxide molecule c. Addition of a carbon dioxide molecule d. Addition of a water molecule e. Addition of a water molecule and a carbon dioxide molecule
a. release of a water molecule
An atom has four electrons in its valence shell. What types of covalent bonds is it capable of forming? a. Single, double, or triple b. Single and double only c. Single bonds only d. Double bonds only
a. single, double, or triple
1. Geckos are able to walk up vertical surfaces because their toes can form hydrogen bonds with the surface they are on. a. True b. False
b. False
1. Saturated fats come from animals and are a liquid at room temperature. a. True b. False
b. False
1. Which of the following molecules will diffuse most quickly across a lipid bilayer membrane? a. H2O b. O2 c. H2PO4- d. Glucose e. Na+
b. O2
1. What is the structural feature that allows DNA to replicate? a. Sugar-phosphate backbone b. Complementary pairing of the nitrogenous bases c. Disulfide bonding (bridging) of the two helixes d. Twisting of the molecule to form an α-helix e. Three-component structure of the nucleotides
b. complementary pairing of the nitrogenous bases
1. The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases. a. S-S bonds b. Hydrogen bonds c. Ionic bonds d. Covalent bonds
b. hydrogen bonds
1. Why is carbon so important in biology? a. It is a common element on earth b. It can form a variety of carbon skeletons and host functional groups c. It has very little electronegativity, making it a good electron donor d. It bonds to only a few other elements
b. it can form a variety of carbon skeletons and host functional groups
1. Suppose you discovered a new amino acid. Its R-group contains hydrogen, oxygen, and carbon atoms. Predict the behavior of this amino acid. a. It is hydrophobic b. It is hydrophilic c. It is basic d. It is nonpolar
b. it is hydrophilic
1. Complementary base pairing is possible only if two DNA strands align in antiparallel - instead of parallel - fashion. Which statement best explains why? a. Only antiparallel strands contain the nitrogenous bases necessary to form complementary base pairs b. Only antiparallel strands create the geometry that allows the complementary base pairs to form via hydrogen bonding c. Only antiparallel strands create the geometry that allows complementary base pairs to form via Van der Waals interactions d. Only antiparallel strands contain unusual backbone atoms which allow complementary base pairing
b. only antiparallel strands create the geometry that allows the complementary base pairs to form via hydrogen bonding
1. The bonding of two monomers to form a larger polymer requires the ______. a. Addition of a water molecule b. Release of a water molecule c. Addition of a carbon dioxide molecule d. Release of a carbon dioxide molecule e. Addition of a water molecule and carbon dioxide molecule
b. release of a water molecule
1. Nucleic acids RNA and DNA differ from each other in ______. a. The order in which the sugars, bases, and phosphate groups are put together to make their nucleotides b. The type of sugar in their nucleotides c. The type of phosphate in their nucleotides d. A and B e. B and C
b. the type of sugar in their nucleotides
How many electrons are involved in a single covalent bond? a. one b. two c. three d. four
b. two
1. Cellulose strands make good building material for plants due to their _______. a. Strong covalent bonds with each other b. Weak hydrogen bonds with each other c. Ring structure
b. weak hydrogen bonds with each other
1. How many covalent bonds can Carbon form? a. 2 b. 3 c. 4 d. 5
c. 4
1. Which of the following descriptions best fits the class of molecules known as nucleotides? a. A nitrogenous base and a phosphate group b. A nitrogenous base and a sugar c. A nitrogenous base, a phosphate group, and a sugar d. A phosphate group and an adenine or uracil e. A sugar and a purine or pyrimidine
c. a nitrogenous base, a phosphate group, and a sugar
When the atoms involved in a covalent bond have the same electronegativity, what type of bond results? a. An ionic bond b. A hydrogen bond c. A nonpolar covalent bond d. A polar covalent bond
c. a non polar covalent bond
1. Which one of the following is NOT a component of each monomer used to make proteins? a. A side chain, R b. A carboxyl group, COOH c. A phosphorous atom, P d. An amino acid functional group, NH2
c. a phosphorus atom, P
1. Which of the following best explains why "carbs" (carbohydrates) are advertised by manufacturers of candy bars and sports drinks as a "quick energy boost"? a. The energy in them can be stored as fat, which has high energy per unit weight b. The carbons in carbohydrates are rich in energy because they are highly oxidized c. Carbohydrates are reduced molecules that have high-energy electrons d. This is an advertising gimmick that has no scientific evidence to support it
c. carbohydrates are reduced molecules that have high-energy electrons
1. _____ atoms give organic molecules their overall shape; _____ atoms determine the overall chemical behavior of organic molecules. a. Carbon; H2O b. Hydrogen; C, N, and O c. Carbon; H, N, and O d. H, N, and O; carbon
c. carbon; H, N, and O
1. What is the difference between covalent bonds and ionic bonds? a. Covalent bonds require carbon while ionic bonds do not b. Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms c. Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms d. Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between charged atoms e. Covalent bonds involve the transfer of electrons between charged atoms; ionic bonds involve the sharing of electrons between atoms
c. covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms
There are 20 different amino acids. What makes one amino acid different from another? a. Different side chains (R-groups) attached to a 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 structural and optical isomers e. Different asymmetric carbons
c. different side chains (R groups) attached to an α carbon
1. Chitin is a major component of the _____. a. Skeleton of mammals b. Hydrostatic skeletons of earthworms c. Exoskeleton of insects d. Body hairs of mammals e. Skeleton in birds
c. exoskeleton of insects
1. The polysaccharide used by animals for fuel is ______. a. Glucose b. Starch c. Glycogen d. Chitin e. Saturated fat
c. glycogen
1. What type of interaction is directly responsible for the formation of the secondary structure in polypeptides? a. Peptide bonds between adjacent amino acids b. Peptide bonds between nonadjacent amino acids c. Hydrogen bonds between sections of the polypeptide backbone d. Hydrogen bonds between side chains of amino acids
c. hydrogen bonds between sections of the polypeptide backbone
1. Diffusion ______. a. Is very rapid over long distances b. Requires an expenditure of energy by the cell c. Is a passive process is which molecules move from a region of higher concentration to a region of lower concentration d. Requires integral proteins in the cell membrane
c. is a passive process is which molecules move from a region of higher concentration to a region of lower concentration
1. Which of the following classes of macromolecules are not involved in the composition of membranes? a. Lipids b. Proteins c. Nucleic acids d. Carbohydrates
c. nucleic acids
1. A covalent chemical bond is one in which _____. a. Electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged b. Protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms c. Outer-shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals d. Outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom e. Electrons from the same atom, but opposite spins, are paired
c. outer shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals
1. If you were going to develop a new antibiotic against bacteria, you would probably need to become an expert on which of these carbohydrates? a. Glycogen b. Chitin c. Peptidoglycan d. Cellulose e. Starch
c. peptidoglycan
1. Which of these correctly sequences the components of a nucleotide? a. Phosphate - sugar b. Phosphate - base c. Phosphate - sugar - base d. Sugar - base - phosphate
c. phosphate-sugar-base
1. A friend of yours calls to say that his car would not start this morning. He asks for your help. You say that you think the battery must be dead. If so, then jump-starting the car from a good battery will solve the problem. In doing so, you are _______. a. Testing a theory for why the car will not start b. Making observations to inspire a theory for why the car will not start c. Stating a hypothesis and using that hypothesis to make a testable prediction d. Comparing multiple hypotheses for why the car will not start
c. stating a hypothesis and using that hypothesis to make a testable prediction
1. At which level of protein structure are interactions between the side chains (R-groups) most important? a. Primary b. Secondary c. Tertiary d. Quaternary e. Primary, secondary, tertiary, and quaternary
c. tertiary
What component of amino acid structure varies among different amino acids? a. the long carbon-hydrogen tails of the molecule b. the presence of a central C atom c. the components of the R group d. the glycerol molecule that forms the backbone of the amino acid
c. the components of the R group
1. Which of the following can vary among monosaccharides? a. The presence of hydroxyl (OH) groups b. The number of sulfur (SH) groups c. The number of carbon atoms d. The presence of a carbonyl (=O) group
c. the number of carbon atoms
1. 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? a. The two strands of the double helix would separate b. The purines would be separated from the deoxyribose sugars c. The phosphodiester bonds between deoxyribose sugars would be broken d. The pyrimidines would be separated from the deoxyribose sugars e. All bases would be separated from the deoxyribose sugars
c. the phosphodiester bonds between deoxyribose sugars would be broken
1. How could two four-sugar polysaccharides be structurally different even if both consist of two glucose monomer and two galactose monomers? a. Only the sequence of monomers along the chain could vary b. Only the location and geometry of glycosidic linkages could vary c. The sequence of monomers along the chain or the location and geometry of glycosidic linkages could vary (or both) d. One polysaccharide could contain aldoses while the other contains ketose
c. the sequence of monomers along the chain or the location and geometry of glycosidic linkages could vary (or both)
1. Which of the following best describes the structure of a biological membrane? a. Two layers of phospholipids with proteins embedded between the two layers b. A mixture of covalently linked phospholipids and proteins that determines which solutes can cross the membrane which cannot c. Two layers of phospholipids with proteins either spanning the layers or on the surface of the layers d. A fluid structure in which phospholipids and proteins move freely between sides of the membrane e. Two layers of phospholipids (with opposite orientations of the phospholipids in each layer) with each layer covered on the outside with proteins
c. two layers of phospholipids with proteins either spanning the layers or on the surface of the layers
1. Upon chemical analysis, a particular polypeptide was found to contain 50 amino acids. How many peptide bonds are present in this protein? a. 52 b. 51 c. 50 d. 49 e. 48
d. 49
1. Why do researchers think the first self-replicating molecule was RNA? a. Fossil evidence of such a molecule was recently discovered b. RNA is the only type of molecule that can catalyze a chemical reaction c. Self-replicating molecules of RNA exist today, in human cells d. RNA can carry information and catalyze chemical reactions
d. RNA can carry information and catalyze chemical reactions
1. Cellulose is _____. a. A polymer composed of fructose monomers b. A storage polysaccharide for energy in plant cells c. Used by plants to make glycogen d. A major structural component of plant cell walls e. A monomer of starch.
d. a major structural component of plant cell walls
1. What affects membrane fluidity? a. Temperature b. % Unsaturated fatty acids c. Cholesterol d. All of the above e. None of the above
d. all of the above
1. What type of interaction is directly responsible for the formation of the tertiary structure in polypeptides? a. Peptide bonds between adjacent amino acids b. Peptide bonds between nonadjacent amino acids c. Hydrogen bonds between sections of the polypeptide backbone d. Hydrogen bonds between side chains of amino acids
d. hydrogen bonds between side chains of amino acids
Which of the following statements best distinguishes scientific hypotheses from scientific theories? a. Hypotheses are generally supported by more evidence than theories b. Hypotheses describe and theories explain c. Hypotheses are used in experiments. Theories are not tested d. Hypotheses are usually narrower in scope; theories have broader explanatory power
d. hypotheses are usually narrower in scope; theories have broader explanatory power
Side chains of amino acids ________. a. are all non polar b. are non polar if they contain N or S c. are all polar d. may be polar or non polar
d. may be polar or non polar
Bonds between two atoms that are equally electronegative are ______. a. hydrogen bonds b. van der waals interactions c. polar covalent bonds d. non polar covalent bonds e. ionic bonds
d. non polar covalent bonds
1. The secondary structure of a protein is the _____. a. Order in which amino acids are joined in a polypeptide chain. b. Bonding together of several polypeptide chains by weak bonds c. Unique three-dimensional shape of the fully folded polypeptide d. Organization of a polypeptide chain into an α-helix or β-pleated sheet via hydrogen bonds e. Overall protein structure resulting from the aggregation of two or more polypeptide subunits
d. organization of a polypeptide chain into an a-helix or B-pleated sheet via hydrogen bonds
1. Lipids that form membranes have what kind of structure? a. Completely nonpolar, because they are lipids b. Completely polar, which allows them to dissolve in water c. Polar heads and nonpolar tails; the nonpolar tails interact with water d. Polar heads and nonpolar tails; the polar heads interact with water
d. polar heads and non polar tails; the polar heads interact with water
1. Why does ice float? a. The high surface tension of liquid water keeps the ice on top b. The ionic bonds between the molecules in ice prevent the ice from sinking c. Ice always has air bubbles that keep it afloat d. Stable hydrogen bonds keep water molecules of ice farther apart that water molecules of liquid water e. The crystalline lattice of ice causes it to be denser that liquid water
d. stable hydrogen bonds keep water molecules of ice farther apart that water molecules of liquid water
1. In the process of science, which of these is tested? a. A conclusion b. An observation c. A result d. A control group e. A hypothesis
e. a hypothesis
1. Enzyme molecules require a specific shape to perform their catalytic function. Which of the following might alter the shape of an enzymatic protein? a. Heating the protein b. Denaturing the protein c. Treating the protein with a chemical that breaks hydrogen bonds d. A change in salt concentrations or pH e. All of the listed responses are correct
e. all of the listed responses are correct
1. Many of water's emergent properties, such as its cohesion, its high specific heat, and its high heat of vaporization, result from the fact that water molecules ______. a. Are in constant motion b. Are extremely large c. Tend to repel each other d. Are very small e. Are attracted to each other with hydrogen bonds
e. are attracted to each other with hydrogen bonds
1. A primary function of carbohydrates attached to the glycoproteins and glycolipids of animal cell membranes is to _____. a. Facilitate diffusion of molecules down their concentration gradients b. Actively transport molecules against their concentration gradients c. Maintain the integrity of a fluid mosaic membrane d. Maintain membrane fluidity at low temperatures e. Mediate cell-cell recognition
e. mediate cell-cell recognition
1. Which of the following is a form of active transport? a. Diffusion b. Osmosis c. Facilitated diffusion d. All of the above e. None of the above
e. none of the above
1. Which of the following specifically describes a polypeptide? a. Amino acids linked by hydrolysis b. Carbohydrates with a hydrogen bond holding them together c. Organic molecules linked by dehydration reactions d. Organic monomers covalently bonded e. None of the above
e. none of the above
1. The number of covalent bonds an atom can form with other atoms is determined by ____. a. The number of neutrons b. The number of protons c. The size of the atom; smaller atoms are chemically more reactive d. The nucleus e. The number of unpaired electrons in the valence shell
e. the number of unpaired electrons in the valence shell