Biology 121 Exam Study Guide – Flashcards
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All living organisms share five fundamental characteristics. Which of the following is not one of these characteristics? -Sexual recombination -Cell -Information -Energy -Evolution
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sexual recombination
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Pasteur's experiment provided conclusive evidence to reject the spontaneous generation hypothesis, which states that cells arise from nonliving material. As a consequence, his results supported the all-cells-from-cells hypothesis. Which element of Pasteur's experimental design was most important and why? -His two treatments differed in the shape of the flask, the type of nutrient broth, and the amount of time the broth was boiled, allowing him to test multiple factors. -His two treatments differed in both the type of nutrient broth and the shape of the flask, resulting in the exposure of only one of the treatments to preexisting cells. -His two treatments differed only in the shape of the flask, resulting in exposure of only one of the treatments to preexisting cells. -His two treatments differed only in the type of nutrient broth used, resulting in the exposure of only one of the treatments to preexisting cells.
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His two treatments differed only in the shape of the flask, resulting in exposure of only one of the treatments to preexisting cells.
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Lance Armstrong just finished third (by about 5 minutes) in the 2009 Tour de France cycling race. This was an incredible feat for the 37-year-old father of 4. First and second-place winners, Alberto Contador (age 27) and Andy Schleck (age 24), respectively, have no children. Which of these three men shows the greatest evolutionary fitness? -Lance Armstrong, because he came in third at the advanced age of 37! -Andy Schleck, because he beat the highly experienced Lance Armstrong. -Lance Armstrong, because he has reproduced. -Alberto Contador, because he won the race.
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Lance Armstrong, because he has reproduced.
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Carl Woese et al. studied small __________molecules and established the concept of the ____________. -DNA; domains -rRNA; genus and species -rRNA; domains -DNA; genus and species
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rRNA; domains
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In the diagram below, "A" is _____ ; "B" is _____. -the common ancestor of life; the common ancestor of Archaea and Eukarya -the common ancestor of all life; the common ancestor of Bacteria and Archaea -the most recent species identified on Earth; the common ancestor of Archaea and Eukarya -the most recent species identified on Earth; an ancestor of group "A"
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answer??
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A hypothesis is considered a theory when: -the results of a single experiment support the hypothesis. -the hypothesis has been revised many times. -the results of several experiments do not support the hypothesis. -the results of several experiments support the hypothesis.
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the results of several experiments support the hypothesis.
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Which of the following statements is true about biological studies? -Hypotheses may be tested by a combination of observation, measurement, and experimentation. -Hypotheses must be tested by making observations or measurements in a natural environment. -Hypotheses must be tested by carrying out experiments. -Hypotheses about biological questions often cannot be tested.
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Hypotheses may be tested by a combination of observation, measurement, and experimentation
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Water has what type bonds? -covalent -ionic -polar covalent -charged -organic
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polar covalent
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How many electrons are involved in a double covalent bond? -one -two -three -four
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four
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An atom has six electrons in it's valence shell. How many single covalent bonds would you expect it to form in most circumstances? -three -two -six -one
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two
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If an atom is electrically neutral, which of the following must be true? -It has the same number of protons as neutrons. -It has the same number of protons as electrons. -It has the same number of neutrons as electrons. -It has at least one more electron than it does protons
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It has the same number of protons as electrons.
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Which of the following is a violation of the first law of thermodynamics? -A hydrogen bomb can destroy a large city with only a few pounds of explosive material. -The universe will eventually die, and it will have no energy left in it. -All of the energy in the universe today was present when the Big Bang occurred. -The amount of energy stored in a plant's cell as sugars after undergoing photosynthesis is less than the amount of sunlight it absorbed.
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The universe will eventually die, and it will have no energy left in it.
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Water also has several remarkable properties, largely due to its ability to form hydrogen bonds. Which property does NOT apply to water? -Adhesive -Denser as a liquid than a solid -Able to absorb large amounts of energy -All of the above are properties of water
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All of the above are properties of water.
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A pH of _____is considered neutral and a pH of ______ is acidic. -7; 9 -4; 6 -7; 3 -9;2 -3; 5
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7; 3
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The energy of movement is called __________ and produces an_______________ reaction. -kinetic energy; endothermic reaction -potential energy; endothermic reaction -kinetic energy; exothermic reaction -potential energy; exothermic reaction
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kinetic energy; exothermic reaction
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Why do chemical reactions tend to speed up when the concentration of the reactants is increased? -The reactants collide more often. -The reactants move faster. -The reactants have greater energy. -All of the above apply.
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The reactants collide more often.
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One carbon atom with four valence electrons combines with ____ hydrogens, each with one valence electron, to fill the outer orbital with _______electrons -2:6 -4:8 -1:5 -8:12
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4;8
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What aspects of amino acid structure vary among different amino acids? -the long carbon-hydrogen tails of the molecule -the glycerol molecule that forms the backbone of the amino acid -the components of the R-group -the presence of a central C atom
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the components of the R-group
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Which one of the following is not a component of each amino acid used to make proteins? -a phosphorous atom, P -an amino functional group, NH2 -a side chain, R -a carboxyl group, COOH
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a phosphorous atom, P
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Polymers of amino acids are formed via _____________ reactions that form ___________ bonds. -condensation; disulfide -hydrolysis; hydrogen -hydrolysis; phosphodiester -condensation; peptide -condensation; glycosidic
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condensation; peptide
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Which of the following observations is the strongest argument in favor of the hypothesis that protein structure and function are correlated? -Proteins have four distinct levels of structure and many functions. -Denatured (unfolded) proteins do not function normally. -Proteins function best at certain temperatures. -Enzymes tend to be globular in shape.
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Denatured (unfolded) proteins do not function normally
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An enzyme has a total of four active sites. When you denature the molecule and study its composition, you find that each active site occurs on a different polypeptide. Which of the following hypotheses does this observation support? -The protein's structure is affected by temperature and pH. -The enzyme is subject to allosteric regulation. -The enzyme requires a cofactor to function normally. -The protein has quaternary structure.
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The protein has quaternary structure.
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The lock-and-key analogy for enzymes applies to the _______. -specificity of enzyme primary, secondary, and tertiary structure -specificity of enzymes binding to their substrate -specificity of enzymes interacting with water -specificity of enzymes interacting with ions -specificity of enzyme tertiary subunits joining to form a quaternary structure
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specificity of enzymes binding to their substrate
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Several of the molecules called vitamins act as enzyme cofactors. Vitamin deficiencies cause disease. What is the most direct explanation for this? -Vitamins combine with nonprotein molecules to delay the onset of disease. -Cofactors inhibit enzymes found in disease-causing bacteria and viruses. When cofactors are absent, these disease-causing agents multiply. -Normal regulation cannot occur in the absence of cofactors. As a result, all enzymes will function all of the time. -If cofactors are missing, enzymes cannot function properly, and important reaction products will be absent from cells.
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If cofactors are missing, enzymes cannot function properly, and important reaction products will be absent from cells.
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The rate of an enzyme-catalyzed reaction depends on four factors. Which of these is not one of these? -Amount of energy available -The enzyme's intrinsic affinity for the substrate -pH -Substrate concentration -Temperature
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Amount of energy available
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When nucleotides polymerize to form a nucleic acid _____. -a covalent bond forms between the sugar of one nucleotide and the phosphate of a second -a hydrogen bond forms between the sugar of one nucleotide and the phosphate of a second -hydrogen bonds form between the bases of two nucleotides -covalent bonds form between the bases of two nucleotides
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a covalent bond forms between the sugar of one nucleotide and the phosphate of a second
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What is the difference between a ribonucleotide and a deoxyribonucleotide? -Ribonucleotides contain a phosphate group. -Ribonucleotides have a hydrogen atom on the 1 carbon of their sugar subunit. -Ribonucleotides contain a sugar with five carbon atoms. -Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit.
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Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit.
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Which of the following includes all of the pyrimidines found in RNA and/or DNA? -cytosine and uracil -cytosine, guanine and thymine -cytosine, uracil, and thymine -adenine and guanine
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cytosine, uracil, and thymine
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A nucleotide is made up of which of the following subunits? -a 5-carbon sugar, a phosphate group, and a nitrogenous base -a 5-carbon sugar and a phosphate group -a 5-carbon sugar and a nitrogenous base -a 5-carbon sugar, an amino group, and an "R-group"
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a 5-carbon sugar, a phosphate group, and a nitrogenous base
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Nucleic acids have a definite polarity, or directionality. Stated another way, one end of the molecule is different from the other end. How are these ends described? -One end has a hydroxyl group on the 2 carbon; the other end has a hydrogen atom on the 2 carbon. -One end contains a nitrogenous base; the other end lacks it. -One end has one phosphate group; the other end has two phosphate groups. -One end has an unlinked 3 carbon; the other end has an unlinked 5 carbon.
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One end has an unlinked 3 carbon; the other end has an unlinked 5 carbon.
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What forms the "backbone" of a nucleic acid? -purine and pyrimidine pairs, hydrogen-bonded to each other -a chain of sugar and phosphate groups, linked through phosphodiester bonds -a chain of amino and carboxyl groups, linked via peptide bonds -a double helix of antiparallel strands
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a chain of sugar and phosphate groups, linked through phosphodiester bonds
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Why do researchers think the first self-replicating molecule was RNA? -Self-replicating molecules of RNA exist today, in human cells. -RNA is the only type of molecule that can catalyze a chemical reaction. -Fossil evidence of such a molecule was recently discovered. -RNA has the capacity to provide a template and is known to catalyze reactions
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RNA has the capacity to provide a template and is known to catalyze reactions.
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In a DNA double helix, the chemical bonds that form between the complementary nitrogenous bases are _____. -phosphodiester bonds -hydrogen bonds -ionic bonds -covalent bonds
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hydrogen bonds
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Which of the following can vary among monosaccharides? -the presence of hydroxyl groups -the presence of a carbonyl group -the number of carbon atoms -all of the above
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the number of carbon atoms
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Which of the following carbohydrates contains a peptide bond? -Carbohydrates don't contain peptide bonds; only proteins do. -chitin -peptidoglycan -cellulose -glycogen
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peptidoglycan
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Carbohydrates perform a wide variety of functions in cell. Which of is not a function of carbohydrates? -serving as raw material for synthesizing other molecules -storing chemical energy -providing structural support -indicating cell identity -All of the above are functions of carbohydrates
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All of the above are functions of carbohydrates.
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Which complex carbohydrate is a storage form of energy in animals? -Cellulose -Glycogen -Starch -All of the above
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Glycogen
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Carbohydrates that function as structural molecules are extraordinarily resistant to degradation and decay. Which structural feature best explains why? -Structural polysaccharides are built with βbeta-1,4-glycosidic linkages, which only a few enzymes can break. -Structural polysaccharides exist as sets of long, parallel strands that are linked to one another. -Structural polysaccharides are built with αalpha-1,4-glycosidic linkages, which are very strong -Structural polysaccharides contain {N}-acetylglucosamine (NAc), which is extremely resistant to decay.
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Structural polysaccharides are built with βbeta-1,4-glycosidic linkages, which only a few enzymes can break
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How do the α and β forms of glucose differ? -Their ring structures differ in the location of a hydroxyl group. -Their linear structures differ in the location of a hydroxyl group. -The α form can be involved in 1,4 and 1,6 glycosidic linkages; the β form can participate only in 1,4 linkages. -The oxygen atom inside the ring is located in a different position.
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Their ring structures differ in the location of a hydroxyl group.
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Which of the following types of molecules have the highest capacity to store chemical energy? -a small molecule rich in C-H bonds, such as ethane -a six-carbon molecule rich in C-H bonds, such as a lipid -a six-carbon molecule rich in C-O bonds, such as a carbohydrate -a small molecule rich in C-O bonds, such as ethanol
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a six-carbon molecule rich in C-H bonds, such as a lipid
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If you were going to develop a new antibiotic, you would probably need to become an expert on which of these carbohydrates? -glycogen -chitin -cellulose -peptidoglycan -starch
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peptidoglycan
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Phospholipid bilayer membranes are selectively permeable. What is meant by the phrase "selectively permeable"? -allows some things to cross while restricting others -allows only water to cross -allows everything nonpolar to cross -allows everything but water to cross -All of these are properties of a selectively permeable membrane
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allows some things to cross while restricting others
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Which aspect of phospholipids is most important to the formation of bilayers? -Their hydrocarbon tails can consist of fatty acids or isoprene subunits -Their size is large, relative to cholesterol. -Their size is small, relative to fats. -They are amphipathic. -All of these are equally important to the formation of bilayers
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They are amphipathic.
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Lipid bilayers are highly selective. What diffuses across this membrane with the most ease? -small, uncharged polar molecules -hydrophilic molecules -large uncharged polar molecules -ions -all of these diffuse across at the same rate.
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small, uncharged polar molecules
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What membrane model is the most accepted by modern science concerning the cell membrane structure? -Sandwich model -Fluid-mosaic model -Cell motive force -Membrane motility model -Structural Functions model
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Fluid-mosaic model
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What distinguishes facilitated diffusion from simple diffusion? -Membrane proteins help move molecules across the membrane. -No energy is used to move molecules across the membrane. -Molecules move from a region of higher concentration to a region of lower concentration. -Water moves through membranes by facilitated diffusion. -ATP is used to move the molecules across the membrane.
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Membrane proteins help move molecules across the membrane.
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Which of the following means of transport would most likely be used for moving a medium-sized molecule (like a monosaccharide or an amino acid) from a low concentration on the outside of a cell to a high concentration on the inside of a cell? -facilitated diffusion through an ion channel protein -active transport through a "pump" protein -facilitated diffusion through a transporter protein -passive transport -all of these methods are used to move these medium sized molecules.
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active transport through a "pump" protein
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____________ fatty acids and ____________ hydrocarbon chains increase membrane permeability. -saturated; long -saturated; short -unsaturated; short -unsaturated; long
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unsaturated; short
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Steroids are ________. -a class of lipid with four-ring structure. -a class of transmembrane transport proteins. -a portion of all phospholipids. -powered by ATP.
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a class of lipid with four-ring structure.
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What will happen to a red blood cell (rbc) which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of pure water? -Nothing. -The cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the rbc. -The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the rbc. -The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the rbc.
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The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the rbc.
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Where would you most likely find an integral protein? -on the inside surface of the cell membrane -on the outside surface of the cell membrane -floating freely in the cytoplasm -spanning the cell membrane, with parts of the protein visible from both the inside and outside of the cell
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spanning the cell membrane, with parts of the protein visible from both the inside and outside of the cell
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Which of the following best explains why "carbs" (carbohydrates) are advertised by manufacturers of candy bars and sports drinks as a "quick energy boost"? -The energy in them can be stored as fat, which has high energy per unit weight. -The carbons in carbs are rich in energy because they are highly oxidized. -Carbs are reduced molecules that have high-energy electrons. -This is an advertising gimmick that has no scientific evidence to support it.
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Carbs are reduced molecules that have high-energy electrons.
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Nucleic acids have a definite polarity, or directionality. Stated another way, one end of the molecule is different from the other end. How are these ends described? -One end has a hydroxyl group on the 2 carbon; the other end has a hydrogen atom on the 2 carbon. -One end contains a nitrogenous base; the other end lacks it. -One end has an unlinked 3 carbon; the other end has an unlinked 5 carbon. -One end has one phosphate group; the other end has two phosphate groups
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One end has an unlinked 3 carbon; the other end has an unlinked 5 carbon.
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You are studying a protein that is shaped like a doughnut. The shape is a function of which level(s) of protein structure? -primary only -secondary only -tertiary only -secondary and tertiary only -primary, secondary, and tertiary
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primary, secondary, and tertiary
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Dairy cattle were unknown in Thai culture until recently, and 97% percent of Thai people are lactose intolerant as adults. Which explanation for such widespread lactose intolerance is most likely correct? -Evolutionarily, producing an enzyme to break down a sugar that will never be encountered is wasteful. -There is no good explanation for this situation in humans. -The ability to digest sugar in milk is determined by environment, and most humans are not exposed to milk as a food source beyond childhood years. -Allergies are becoming more common in humans as more chemicals are being encountered during longer lifetimes.
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Evolutionarily, producing an enzyme to break down a sugar that will never be encountered is wasteful.
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Which of the following phospholipid membranes would be most permeable to glycerol? -one with long and saturated fatty-acid tails -one with long and unsaturated tails -one with short and saturated tails -one with short and unsaturated tails
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one with short and unsaturated tails
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Kangaroo rats live in the desert of the southwestern United States. They have many adaptations to minimize water loss. They obtain a small amount of water from seeds that they eat. However, the rest of the water they obtain is from cellular respiration. -This cannot be true, as cellular respiration doesn't really "produce" water. -This cannot be true, as water is actually consumed in cellular respiration. -This could be true, as water is produced in cellular respiration. -This could be true, as water is produced in glycolysis. -This could be true, as water is produced in the citric acid cycle.
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This could be true, as water is produced in cellular respiration.
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The approximate yield of ATP molecules from the full oxidation of a molecule of glucose is: -2. -6. -12. -32. -64.
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32
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In which form are electrons transferred during typical redox reactions such as the oxidation of glucose? -as free electrons -as hydrogen atoms -as oxygen atoms -as carbon atoms -as phosphate groups
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as hydrogen atoms
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Which is not a stage of cellular respiration? -citric acid cycle -glycolysis -oxidative phosphorylation -photosynthesis
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photosynthesis
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Which one of the following represents the reduced forms of the two major electron carriers? -NAD+ and FAD -NAD+ and FADH2 -NADH and FAD -NADH and FADH2
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NADH and FADH2
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Cellular respiration is a series of _____ reactions. A. catabolic B. anabolic C. glycolytic D. phosphorylation E. carboxylation
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catabolic
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The electron transport chain is part of: -glycolysis. -the citric acid cycle. -oxidative phosphorylation. -fermentation. -pyruvate oxidation.
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oxidative phosphorylation.
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In the first three stages of cellular respiration, the chemical energy in glucose is transferred to: -ATP and cytochrome b. -electron carriers and ATP. -cytochrome b and coenzyme Q. -proton pumps and ATP. -only coenzyme Q.
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electron carriers and ATP.
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A molecule that is ______ loses electrons, and a molecule that is ______ gains electrons. -reduced; oxidized -negative; positive -oxidized; reduced -weak; polar -None of the other answer options is correct.
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oxidized; reduced
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In eukaryotes, pyruvate oxidation takes place in the: -cytoplasm. -outer mitochondrial membrane. -inner mitochondrial membrane. -intermembrane space of mitochondria. -mitochondrial matrix.
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mitochondrial matrix.
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Which of the following sequences correctly represents the flow of energy through living systems? -light --> photosynthesis --> carbohydrate --> cellular respiration --> ATP --> heat -water --> photosynthesis --> carbohydrate --> cellular respiration --> ATP --> CO2 -water --> photosynthesis --> carbohydrate --> cellular respiration --> ATP --> water -light --> photosynthesis --> carbohydrate --> cellular respiration --> ATP --> water -CO2 --> photosynthesis -> carbohydrate --> cellular respiration --> ATP --> heat
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light --> photosynthesis --> carbohydrate --> cellular respiration --> ATP --> heat
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In plants and algae, __________ is the source of the electrons needed for photosynthesis. -O2 -CO2 -H2O -NADPH -H+
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H2O
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During photosynthesis in plants and algae, __________ is oxidized and __________ is reduced. -O2; CO2 -CO2; H2O -H2O; O2 -H2O; CO2 -NADPH; ATP
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H2O; CO2
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Where does the oxygen come from that is produced as a by-product of photosynthesis? -from the reduction of CO2 -from breakdown of water -from the breakdown of carbohydrates -from the Calvin cycle
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from breakdown of water
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Beginning with the step catalyzed by rubisco, arrange the steps in the Calvin cycle in the proper sequence in which they occur. -carboxylation, reduction, regeneration -reduction, regeneration, carboxylation -regeneration, carboxylation, reduction -carboxylation, regeneration, reduction -reduction, carboxylation, regeneration
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carboxylation, reduction, regeneration
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The most abundant protein on Earth is thought to be: -chlorophyll. -cellulose. -rubisco. -water. -keratin.
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rubisco
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The primary reason surplus carbohydrates in plants are stored as starch is because: -they would otherwise be utilized as energy sources even if such energy were not needed at that time. -the space they occupy as carbohydrates is needed for other macromolecules. -energy is needed in the nucleus, and only starch is capable of being transported into the nucleus. -if they were left as individual monosaccharides, water would enter the cell by osmosis. -All of these choices represent equally important reasons why surplus carbohydrates in plants are stored as starch.
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if they were left as individual monosaccharides, water would enter the cell by osmosis.
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Which of the following correctly lists the path taken by electrons through the light dependent reactions of photosynthesis? -NADPH --> photosystem I --> cytochrome b6f --> photosystem II --> water -water --> photosystem I --> cytochrome b6f --> photosystem II --> NADPH -water --> photosystem II --> cytochrome b6f --> photosystem I --> NADPH -NADPH --> photosystem II --> cytochrome b6f --> photosystem I --> water
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water --> photosystem II --> cytochrome b6f --> photosystem I --> NADPH
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In photosynthesis, the electrons from _____________________ are used to reduce ___________________. A. water; carbon dioxide B. oxygen; carbohydrates C. oxygen; NADPH D. water; carbohydrates
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water; carbon dioxide
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ATP production in photosynthesis requires: -light. -electrons. -protons. -light and protons. -light, electrons, and protons.
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light, electrons, and protons.
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What occurs when the signal causes release of dopamine in the brain, which causes relaxation and feelings of well-being? -receptor binding. -receptor activation. -signal transduction. -response. -termination.
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response.
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A protein on a cell surface that binds to a signaling molecule is an example of which of the following elements of cellular communication? -a signaling cell -a signaling molecule -a receptor protein -a responding cell -None of the other answer options is correct.
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a receptor protein
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To have communication between cells, you must have a: -receptor. -signaling molecule. -responding cell. -All of these choices are correct.
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All of these choices are correct.
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The opening of an ion channel as a result of nicotine binding is an example of: -receptor binding. -receptor activation. -signal transduction. -response. -termination.
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receptor activation.
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What occurs when the signal causes release of dopamine in the brain, which causes relaxation and feelings of well-being? -receptor binding. -receptor activation. -signal transduction. -response. -termination
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response
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Choose from the following terms to fill in the blanks in the correct order. A. ligand B. signaling cell C. receptor D. responding cell In communication between cells, the _____________________ produces the signaling molecule, also known as the ________________; the ______________________ produces the _______________, to which the signaling molecule binds. -B, A, D, C -A, B, C, D -B, C, A, D -D, C, B, A
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B, A, D, C
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A cell that responds to an environmental condition by the release of a chemical is an example of which of the following elements of cellular communication? -a signaling cell -a signaling molecule -a receptor protein -a responding cell -None of the other answer options is correct.
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a signaling cell
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Signal transduction results in: -a change in the conformation of the receptor protein. - a response by the cell. - production of more signal molecules. - termination of the signal.
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-a response by the cell.
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Of the choices below, what is the most likely reason that paracrine signaling does not activate the cell that is producing the signaling molecule? - The concentration of the signaling molecule is not high enough. - The neighboring cells are too far away. -. The cell does not have the proper receptor. - The cell's receptors have a mutation.
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-The cell does not have the proper receptor
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Platelet-derived growth factor (PDGF) is a signaling molecule that functions in which of the following types of cell signaling? -contact-dependent - paracrine - autocrine - endocrine - All of these choices are correct.
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-paracrine
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Which of the following statements about mammalian skin is incorrect? .-The epidermis is an outer layer that provides a water-resistant, protective barrier. - The dermis is the layer below the epidermis containing connective tissue, blood vessels, and nerve endings that provides nutrients to the epidermis and a cushion layer for the body. - Epithelial cells in the epidermis are primarily composed of keratinocytes that protect underlying tissue. - A specialized form of extracellular matrix, called the basal lamina, underlies the dermis and separates it from tissues below. - Fibroblasts in the dermis produce extracellular matrix proteins to make the dermis strong and flexible.
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-A specialized form of extracellular matrix, called the basal lamina, underlies the dermis and separates it from tissues below.
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Which is the correct order from lesser to greater complexity for the following? -organs, tissues, cells - cells, tissues, organs -tissues, organs, cells - cells, organs, tissues
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cells, tissues, organs
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Which of the following structures are responsible for the shape of a cell? - microvilli - cytoskeleton - cell junctions - organelles
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cytoskeleton
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. The basal lamina is: - an area found beneath all connective tissues that helps them adhere to underlying muscle. - a specialized form of the extracellular matrix found beneath all epithelial tissues. - a specialized form of the extracellular matrix found only in the skin. - an area found wherever two different types of tissues meet.
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a specialized form of the extracellular matrix found beneath all epithelial tissues.
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A pathologist is carrying out an autopsy. Upon opening the chest cavity, the pathologist sees a thick, fibrous tissue surrounding the heart. This is likely: - neural tissue. - epithelial tissue. - muscle tissue. -connective tissue
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connective tissue
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Which of the following structures would be located in the dermis of the skin? - nerve endings -connective tissue - sweat glands - blood vessels - All of these choices are correct.
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all of these choices are correct
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The cytoskeleton of animal cells includes: -microtubules, microfilaments, and intermediate filaments. -actin, microfilaments, and intermediate filaments. - actin, microtubules, and intermediate filaments. - tubulin, microfilaments, and intermediate filaments. - microtubules and microfilaments.
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- microtubules, microfilaments, and intermediate filaments.
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Myosin motor proteins use ATP to: - carry vesicles along a microtubule within a cell in a minus-to-plus direction. - carry vesicles along a microfilament within a cell in a minus-to-plus direction. - carry vesicles along a microtubule within a cell in a plus-to-minus direction. - carry vesicles along a microfilament within a cell in a plus-to-minus direction. - slide along intermediate filaments to contract muscle cells.
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-carry vesicles along a microfilament within a cell in a minus-to-plus direction
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Cilia and flagella: - are specialized cells that move by rotary motion. - are specialized organelles that move by rotary motion. - are specialized organelles that propel some algae, plant, and animal cells. - contain microfilaments arranged in nine pairs around the periphery and two microfilaments in the center. - contain microtubules arranged in nine pairs around the periphery and two microfilaments in the center.
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are specialized organelles that propel some algae, plant, and animal cells.
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Dynamic instability is a: -feature of microtubules. - feature of microfilaments. - feature of intermediate filaments. - feature of microtubules and microfilaments. - universal feature of the cytoskeleton
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feature of microtubules
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The correct sequence of steps in the eukaryotic cell cycle is: -. G1 S phase G2 mitosis cytokinesis. - G0 S phase G1 S phase G2 mitosis cytokinesis. - G0 S phase G1 G2 cytokinesis mitosis. - G0 S phase G1 S phase G2 cytokinesis mitosis. - G1 S phase G2 cytokinesis mitosis.
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G1 S phase G2 mitosis cytokinesis.
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Prokaryotic cells and eukaryotic cells reproduce by mitotic cell division. Regardless of the type of cell, all cells must __________________ before they divide. - make a copy of their genetic information - separate sister chromatids from one another - complete mitosis - reconstruct their nucleus
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-make a copy of their genetic information
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. Which of the following is not true about the eukaryotic cell cycle? - There are two stages to the cell cycle: M phase and interphase. - The M phase consists of two events: mitosis and cytokinesis. - Interphase is typically the shortest of the two stages of the cell cycle. - There are three phases of interphase: the S phase and two gap phases. - Some cells pause between M phase and S phase for more than a year.
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-Interphase is typically the shortest of the two stages of the cell cycle.
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A skin cell in G2 of interphase has _______________ as much DNA as it had in G1. -. half - twice - exactly - one-fourth - four times
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twice
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All of the following happen during mitosis except: -. condensing of chromosomes. - synthesis of DNA. - formation of the spindle. - separation of sister chromatids at the centromeres
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synthesis of DNA.
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Paramecium is a single-cell eukaryotic organism that can reproduce by mitotic cell division. Prior to the M phase of the cell cycle, which of the following must occur? - The cell must replicate its chromosomes. -The cell must first be fertilized. - The nucleus must divide. - Sister chromatids must be separated. - The nuclear envelope must disintegrate.
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-The cell must replicate its chromosomes.
question
The division of the cell's cytoplasm in a eukaryotic cell is known as: -cytokinesis. - cell fission. - mitosis. - both cytokinesis and mitosis.
answer
cytokinesis.
question
The correct sequence of steps in the M phase of the cell cycle is: - prophase, prometaphase, metaphase, anaphase, telophase, nuclear division. - prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis. - prophase, metaphase, prometaphase, anaphase, nuclear division, telophase. - prophase, metaphase, anaphase, telophase, cytokinesis, nuclear division.
answer
-prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.
question
Sister chromatids are best described as two DNA molecules that have: - the same genes in the same order but having different alleles. - the same alleles of the same genes in a different order. - different genes in the same order and possibly having different alleles of some genes. - different alleles of the same genes arranged in a different order. - virtually identical sequences of nucleotides.
answer
virtually identical sequences of nucleotides
question
What is the function of histone proteins? - to package DNA in eukaryotic chromosomes - to connect chromosomes to the mitotic spindle - to organize the microtubules that make up the spindle - to attach sister chromatids together
answer
to package DNA in eukaryotic chromosomes
question
What is a major difference in the extracellular matrix (ECM) between plant and animal cells? - Plant ECM is composed primarily of proteins, whereas animal ECM is mainly carbohydrates. - Plant ECM is primarily carbohydrate in nature, whereas animal ECM is largely protein based. - Plant and animal ECMs are quite similar in structure and function. -Plant ECM components are released extracellularly by the Golgi stacks, whereas lysosomes function in this capacity in animal cells.
answer
Plant ECM is primarily carbohydrate in nature, whereas animal ECM is largely protein based.
question
The production of alcohol or lactate from pyruvate during __________ occurs as a means of regenerating __________ from __________. - aerobic respiration; ATP; ADP - fermentation; ADP; ATP - fermentation; NADH; NAD+ - aerobic respiration; NAD+; NADH - fermentation; NAD+; NADH
answer
fermentation; NAD+; NADH
question
Why are there several structurally different pigments in the reaction centers of photosystems? - Excited electrons must pass through several pigments before they can be transferred to electron acceptors of the electron transport chain. - This setup enables the plant to absorb energy from sunlight from a variety of wavelengths. - They enable the plant to absorb more photons from light energy, all of which are at the same wavelength. - They enable the reaction center to excite electrons to a higher energy level.
answer
This setup enables the plant to absorb energy from sunlight from a variety of wavelengths.
question
Which of the following statements is NOT true of mitosis? - A single nucleus gives rise to two identical daughter nuclei. - The daughter nuclei are genetically identical to the parent nucleus. - The centromeres divide at the onset of anaphase. - Homologous chromosomes synapse in prophase.
answer
Homologous chromosomes synapse in prophase.
question
A human cell has 46 total or 23 pairs of chromosomes. Following mitosis, the daughter cells would each have a total of ______ chromosomes. After meiosis I, the two daughter cells would have _____chromosomes, and after meiosis II ______ chromosomes. - 46, 46, 46 -. 46, 23, 23 - 23, 23, 23 -. 46, 12, 12
answer
46, 23, 23
question
A student was studying cell growth using cells grown in laboratory cultures. The cultures were synchronized so that all of the cells passed through the same stage of the cell cycle at the same time. The cells were examined during five different periods of time, intervals (A-E). The amount of DNA present per cell was determined for each interval. The graph shows the result of this study. 1. Most of the cells examined during interval A have half as much DNA as those measured in interval C. Therefore, most of the cells at interval B must have been in: -. G0. -. M phase. -. S phase. -. G1. -. G2.
answer
S phase
question
. Most of the cells examined during interval D were in: -S phase. - G1. -. G2. -. cytokinesis. -. mitosis.
answer
- cytokinesis
question
The correct sequence of steps in the eukaryotic cell cycle is: -. G1 S phase G2 mitosis cytokinesis. -. G0 S phase G1 S phase G2 mitosis cytokinesis. -. G0 S phase G1 G2 cytokinesis mitosis. -. G0 S phase G1 S phase G2 cytokinesis mitosis. -. G1 S phase G2 cytokinesis mitosis
answer
-G1 S phase G2 mitosis cytokinesis
question
Which of the following is not true about the eukaryotic cell cycle? -. There are two stages to the cell cycle: M phase and interphase. -. The M phase consists of two events: mitosis and cytokinesis. -. Interphase is typically the shortest of the two stages of the cell cycle. -. There are three phases of interphase: the S phase and two gap phases. -. Some cells pause between M phase and S phase for more than a year.
answer
Interphase is typically the shortest of the two stages of the cell cycle.
question
A skin cell in G2 of interphase has _______________ as much DNA as it had in G1. - half -. twice -. exactly -. one-fourth -. four times
answer
- twice
question
Paramecium is a single-cell eukaryotic organism that can reproduce by mitotic cell division. Prior to the M phase of the cell cycle, which of the following must occur? -. The cell must replicate its chromosomes. - The cell must first be fertilized. -. The nucleus must divide. -. Sister chromatids must be separated. -. The nuclear envelope must disintegrate.
answer
The cell must replicate its chromosomes.
question
A gene associated with promoting normal cell division is called: -. an oncogene. -. a proto-oncogene. -. a tumor suppressor. -. a proto-oncogene or a tumor suppressor
answer
a proto-oncogene
question
An enzyme that catalyzes the addition of a phosphate group from ATP to another molecule is called a: -. phosphatase. -. phosphorylase. -. kinase. -. cyclase.
answer
kinase.
question
. In observing DNA replication in the lab, you notice that in some cells, a defect occurs where DNA replication proceeds, but the RNA primers are not removed and replaced with DNA. Which enzyme is most likely to be defective in this system? -. RNA primase -. helicase -. single-strand binding protein -. DNA polymerase -. DNA ligase
answer
-DNA polymerase
question
The fact that DNA replication occurs in virtually the same way in all organisms reflects: -. its origin early in the history of life. -. its multiple origins in different lineages of organisms. -. the laws of thermodynamics. -. the fact that mutations are generally harmful. -. the universal genetic code.
answer
its origin early in the history of life
question
_________ relieves the tension on the double helix during DNA replication. -. Helicase - Topoisomerase -. DNA polymerase -. A single-stranded binding protein -. An RNA primer
answer
Topoisomerase
question
Which of the following statements about the strands of a newly replicated DNA molecule is correct? -. Both strands are made up of newly assembled nucleotides. -. One strand is new and the other is from the original molecule. -. Both strands contain some nucleotides from the original molecule. -. The sugar-phosphate chains are conserved and new bases are inserted between them. - The base pairs are conserved and new sugar-phosphate backbones are built up on them.
answer
One strand is new and the other is from the original molecule.
question
. Energy is required in order to add a nucleotide to the growing strand of DNA during replication. From where does that energy come? -. DNA polymerase -. DNA ligase -. helicase -. primase -. the incoming nucleotide
answer
the incoming nucleotide
question
RNA is involved in which of the following cellular processes? -. transcription -. transcription and translation -. translation and DNA replication -. DNA replication and transcription -. DNA replication, transcription, and translation
answer
DNA replication, transcription, and translation
question
Telomerase is fully active in _____ and _____ cells, but almost completely inactive in ____ cells. -. germ; somatic; stem -. germ; stem; somatic -. stem; blood; germ -. somatic; blood; germ -. somatic; germ; stem
answer
germ; stem; somatic
question
Which of the following statements is true regarding chromosome replication in eukaryotes? -. During chromosome replication, multiple origins of replication form for all DNA in a cell. -. Replication bubbles remain distinct, isolated structures during chromosome replication and never fuse with one another. -. In humans, it takes several days to replicate an entire chromosome. -. Replication begins at one end of the chromosome and proceeds until it reaches the opposite end. -. None of the other answer options is correct.
answer
During chromosome replication, multiple origins of replication form for all DNA in a cell
question
A shotgun sequencing project yields the following sequence for a strand of DNA. 5'-GGTTTGGAGTAT-3' Which of the following sequences overlap with the sequence above? -. 5′-GGTTTTTAGACT-3′ -. 5′-GTGTTGGAGCTT-3′ -. 5′-GAGTATCCAAAT-3′ -. 5′-GGCTTGAGGTTA-3′ -. None of the sequences overlaps with the sequence above
answer
. 5′-GAGTATCCAAAT-3′
question
Genome sequencing includes the following steps: 1. putting the sequences in the correct order 2. matching regions of overlap 3. breaking the DNA into small fragments 4. reconstructing the long sequence of nucleotides 5. sequencing the DNA In what order are these steps carried out? -. 1-2-3-4-5 -. 5-2-3-1-4 -. 3-5-2-1-4 -. 3-5-2-4-1 -. 5-4-3-2-1
answer
3-5-2-1-4
question
Sometimes a single-stranded molecule of RNA is able to fold back on itself because the nucleotide sequence on one part of the RNA is complementary to another part. This sequence motif results in a: -. transcription factor binding site. -. hairpin-shaped structure. -. chromosome scaffold. -. negative supercoil. -. positive supercoil.
answer
hairpin-shaped structure
question
. All of the genetic material transferred from a parent to an offspring is known as a: -. karyotype. -. genome. -. open reading frame. -. nucleoid. -. mRNA.
answer
genome.
question
. Which of the following would be found in DNA sequences but not in mRNA sequences? -. transcription start sites -. translation start sites -. open reading frames -. exons -. All of these choices are correct.
answer
. transcription start sites
question
The genome of a virus can contain which of the following? -. genes that code for surface proteins -. genes that code for components of the capsid -. genes that code for reverse transcriptase -. genes that code for proteases -. All of these choices are correct.
answer
All of these choices are correct
question
The size of a genome is measured by: -. the number of base pairs. -. gene size. -. the number of chromosomes. -. the size of organism. -. All of these choices are correct.
answer
the number of base pairs
question
Transposable elements are: -. proteins that can move outside of the nucleus. -. proteins that can move into the nucleus. -. DNA sequences that can insert themselves into RNA. -. DNA sequences that can insert themselves into new positions within the genome. -. None of the other answer options is correct.
answer
DNA sequences that can insert themselves into new positions within the genome.
question
Why do mutations associated with cancer almost always occur sequentially instead of simultaneously? -. The mutations are extremely unlikely to occur in the same cell at the same time. -. Each mutation increases cellular growth rate, allowing more cells to have a higher chance of the next mutation. -. Each mutation adds to the growth advantage of the ones occurring previously. -. All of these choices are correct.
answer
All of these choices are correct
question
A family can share a genetic risk of developing cancer if: -. the cancer is caused by somatic cell mutations. -. the cancer is caused by germ-line mutations. -. a germ-line mutation in one of the genes implicated in the cancer occurred in an ancestor. -. a somatic cell mutation in one of the genes implicated in the cancer occurred in an ancestor. -. All of these choices are correct.
answer
-a germ-line mutation in one of the genes implicated in the cancer occurred in an ancestor.
question
Sites in the genome that are more susceptible to mutations than others are called: -. mutation spots. -. hotspots. -. risk factors. -. genes. -. noncoding DNA.
answer
- hotspots.
question
Which of the following would you expect to have the lowest rate of point mutations per replication? -. bacteria -. DNA viruses -. RNA viruses -. fruit flies -. human
answer
human
question
Which of the following statements applies to frameshift mutations? -. They cause the insertion or deletion of a single amino acid from the polypeptide chain. -. They create a premature stop codon at the site of mutation. -. They change the amino acid sequence downstream from the mutant site. -. They are known risk factors in most forms of cancer, including breast and colon cancer. -. They are known risk factors in breast cancer, but not colon cancer.
answer
They change the amino acid sequence downstream from the mutant site.
question
Which of the following is most likely to result in a nonfunctional polypeptide? -. a silent mutation -. a missense mutation -. a nonsense mutation -. a transition mutation -. Silent and missense mutations are the most likely to result in a nonfunctional polypeptide.
answer
a nonsense mutation
question
Which of the following statements about mutations is true? A mutation: -. may leave the amino acid sequence of a protein unchanged. -. will result in a different phenotype. -. will be corrected. -. will be passed onto offspring. -. None of the other answer options is correct.
answer
may leave the amino acid sequence of a protein unchanged.
question
. A point mutation that changes a UAC codon into a UAG codon is a: -. missense mutation. -. nonsense mutation. -. silent mutation. -. frameshift mutation.
answer
-nonsense mutation.
question
The phenotype of an individual results from an interaction between: -. allele frequency and mutation rate. -. allele frequency and genotype. -. genotype and mutation rate. -. genotype and the environment. -. allele frequency and the environment
answer
genotype and the environment.
question
Which of the following statements best describes the effect of having the S allele, which codes for sickle-cell anemia? -. Having the allele is always harmful. -. Having the allele is always beneficial. -. The effect depends on whether the allele occurs in its homozygous or heterozygous form. -. The effect depends on the environment (i.e., whether malaria is present). -. The effect depends on whether the allele occurs in its homozygous or heterozygous form, and the environment (i.e., whether malaria is present).
answer
The effect depends on whether the allele occurs in its homozygous or heterozygous form, and the environment (i.e., whether malaria is present).
question
An individual is homozygous for a gene if: -. the mother is homozygous for the gene. -. the father is homozygous for the gene. -. they developed from a sperm and an egg that carried the same allele. -. they developed from a sperm and an egg that carried different alleles. -. None of the other answer options is correct.
answer
. they developed from a sperm and an egg that carried the same allele.
question
Which statements about mutations are false? -. Mutations make evolution possible. -. Mutations result in genetic variation among individuals. -. Mutations accumulate in a genome over time. -Mutations are usually caused by exposure to radiation. -. Mutations can be harmful, beneficial, or neutral
answer
Mutations are usually caused by exposure to radiation.
question
Any difference among individuals that is sufficiently common such that it would almost certainly be present in a group of 50 individuals chosen at random" is the definition of a(n): -. allele. -. genotype. -. polymorphism. -. restriction site. -. phenotype.
answer
polymorphism.
question
Which one of the following best describes genotype-by-environment interactions? -. Genetic and environmental factors combine to influence phenotype. -. The genotype of an organism determines how that organism will behave in its environment. -. The environment of an organism determines the genetic make-up of that organism. -. Under certain circumstances, two organisms with identical genotypes have different phenotypes. -. Under certain circumstances, two organisms with identical phenotypes have different genotypes.
answer
Genetic and environmental factors combine to influence phenotype.
question
Which one of the following statements about restriction fragment length polymorphisms (RFLPs) is correct? -. RFLPs are the product of cleavage by restriction enzymes. -. RFLPs are variations in restriction sites that result in DNA being cleaved into different-sized pieces. -. RFLPs are numerous in the human population. -. RFLPs can take the place of VNTRs in forensic analyses. -. All of these choices are correct.
answer
All of these choices are correct
question
In England, a man who is upset about the amount of dog feces on his lawn supposedly collected hair samples from neighborhood dogs and compared their DNA types with that of the feces, thereby identifying the offending dog (and the negligent owner). It this possible? -. This is not only possible, but it is fairly easy. -. This is ridiculous—no way. -. It might be possible, but it would cost hundreds of thousands of dollars. -. It's an urban legend, so forget it.
answer
This is not only possible, but it is fairly easy.
question
. ______ suggests that traits in offspring resemble the average of the parents. -. Mendelian inheritance -. Natural selection -. Blending inheritance -. Eugenic inheritance
answer
Blending inheritance
question
In a reciprocal cross: -. both parents are male. - both parents are female. -. heterozygous genotypes are crossed with homozygous genotypes. -. the sexes are interchanged relative to the trait.
answer
the sexes are interchanged relative to the trait.
question
In Mendel's garden peas, each cell in a pea plant has a total of: -. one allele for each gene. -. two alleles for each gene. -. one allele for each gene, if it is a true-breeding parent and two if it is an F1 offspring. -. one allele for each gene, if it has green seeds and two if it has yellow seeds. -. between one and four alleles for each gene.
answer
two alleles for each gene
question
. An allele is: -. one of several forms of a gene. -. the particular combination of genes for a given trait in a given organism. -. the expression of a trait in an individual. -. the location of a gene on a chromosome. -. None of the other answer options is correct.
answer
one of several forms of a gene.
question
In genetic crosses, the symbol Aa refers to a: -. genotype. -. phenotype. -. morphotype. -. holotype. -. archetype.
answer
genptype
question
Which of the following was not a trait that Mendel studied in pea plants? -. leaf size -. seed color -. flower color -. plant height -. seed shape or texture
answer
leaf size
question
Which of the following statements is true regarding Mendel's work? -. He did not use true-breeding pea strains. -. He provided no numerical or statistical data for any of his experiments. -. He focused on a subset of easily discernible traits in pea plants. -. His work utilized several different traits and several different strains of pea plants, some of which were not considered true-breeding. -. All of these choices are correct.
answer
He focused on a subset of easily discernible traits in pea plants.
question
Which of the following ratios is associated with Mendel's discoveries? -. 3:1 -. 1:2 -. 1:2:1 -. 9:3:3:1 -. All of these choices are correct.
answer
All of these choices are correct.
question
A wild-type fruit fly: -. exhibits a mutant phenotype. - exhibits the most common phenotype in the population. -. exhibits a phenotype that marks it as a party animal. -. expresses a large proportion of homozygous recessive alleles. -. will most likely have white eyes.
answer
exhibits the most common phenotype in the population.
question
. In fruit flies, an X chromosome carrying the allele for white eyes is transferred from a male to a female of the next generation and in the next generation is transmitted back to the male again. This is called: -. Morgan inheritance. -. crisscross inheritance. -. incomplete penetrance. -. epistasis.
answer
crisscross inheritance
question
. the development of cancer requires both the _______ of an oncogene and the ________ of a tumor suppressor. -. activation; activation -. activation; inhibition -. inhibition; activation -. inhibition; inhibition
answer
activation; inhibition
question
The enzyme _____ compensates for chromosomes shortening at the tips after each round of DNA replication. -. DNA polymerase -. telomerase -. topoisomerase II -. DNA ligase -. DNA replicase
answer
telomerase
question
The C-value paradox applies to: -. viruses -. archaea -. bacteria -. eukaryotes -. All of these choices are correct
answer
eukaryotes
question
Chromosomal mutations that are most likely to cause serious damage to an organism are those that affect the: -. centromere. -. telomere. -. long arm of the chromosome. -. short arm of the chromosome. -. None of the other answer options is correct
answer
centromere
question
You are working in a medical research lab and have to determine if a patient is heterozygous or homozygous for a particular restriction site. You isolate a region of DNA from each chromosome, the middle of which could contain the restriction site, if the patient has it. If you treat the DNA with the restriction enzyme, how many fragments will be produced if the patient is heterozygous for the presence of the restriction site? -. one -. two -. three -. four -. This question is impossible to answer based on the information provided.
answer
three
