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Bio12 Chapter2TestReview 1.Knowthedifferencebetweenionicandcovalentbonds Inordertocompleteoutershellsinelectronsbondscanbe Ionic;oneatomdonatesorreceiveselectrons Covalent;atomsshareelectrons 2.Knowwhatapolarcovalentbondis: bondthathasUNEQUALsharingofelectrons 3.Beabletoexplainwhywaterisapolarmolecule *Polarbondshavechargesoneitherendandoftenattracttoeachother *Atoms‘hogging’theelectronshaveanelectronegativecharge,andatoms ‘lacking’electronshaveanelectropositivecharge 4.Explainwhatahydrogenbondisandwhyitisimportant Electronegativeatomsononemoleculeareattractedtoelectropositiveatoms onadifferentmolecule.FormHydrogenbonds. 5.Explaintheuniquecharacteristicsofwaterandexplainhowtheyareuseful toorganisms(posteryoumade) *Watermoleculesareattractedtootherpolarmolecules cohesion–whenonewatermoleculeisattractedtoanotherwatermolecule adhesion–whenpolarmoleculesotherthanwatersticktoawatermolecule(Steady columnofwater) *Waterwarmsupandcoolsdownslowly(highheatcapacity) *Waterhasahighheatofvaporizationbecausesomanyhydrogenbondsmustbe brokenforwatertoevaporate *Asolutionconsistsofasolutedissolvedintoasolvent *Water’shydrogenbondshelpitdissolveotherpolarmolecules *FrozenWaterisLessDensethanLiquidWaterandfloatsonliquidwater 6.ExplainthedifferencebetweenanacidandabaseandwhatpHis. pHistheMeasurementofAcidity(acid)orAlkalinity(base)ofaSolution. ThepHscalegoesfrom0to14 -pH0isacidic -pH7isneutral -pH14isbasic ThegreatertheH+concentration, thelowerthepH Thelowerthehydrogenionconcentration,thehigherthepH 7.Definebufferandexplainitsroleinbiologicalsystems BuffersHelpKeepthepHofBodyFluidsRelativelyConstant BufferSystem:thecombinationofaweakacidandthebasethatformswhenthe aciddissolvesinwater BybindingorreleasingH+’s,itmaintainsaconstantconcentrationoffreeH+’sinthe solution 8.Explainhowdifferencesincarbonskeletonandattachedfunctionalgroups causeorganicmoleculestohavedifferentchemicalproperties Ahydrocarbonchaincanturnbackonitselftoformaringcompound,oraspiralor aseriesoffoldsduetotheinteractionbetweentheatomsandthefunctionalgroups. Functionalgroupsarespecificcombinationsofbondedatomsthatalwaysreactin thesameway. 9.Explainthedifferencebetweenhydrophobicandhydrophilic • Hydrophilic(water-loving)moleculesformhydrogenbondswithwater • Hydrophobic(water-fearing)moleculesdonotformhydrogenbondswith water 10.Differentiatebetweenthefourclassesofmacromoleculesandbeableto identifythemfromapictureoftheirstructure 1) Carbohydrates monomer 2) Proteins polymer(Chitin) 3) Lipids Which Is a Source of Unsaturated Fatty Acids? Linseed Oil Beef Fat Est 4) NucleicAcids-formedwithribosesugar,phosphateandnitrogenousbase P P P P 11.Explaintherelationshipbetweenmonomersandpolymersofthe macromolecules(glucosevsstarch,aminoacidsandproteins…) Monomerorbuildingblocks polymer glucose Starch,celluloseorglycogen,chitin Aminoacid proteins Glycerolandfattyacids Lipids(alsoSteroids,Waxes) Nucleotides(sugar,phosphategroupand DNA,RNA,ATP nitrogenousbase) 12.Differentiatebetweendehydrationsynthesisandhydrolysisandmake suretounderstandwhetherwaterisaddedorremovedandwhetherenergyis releasedorrequiredinthereaction Bytakingoutawatermolecule(hydroxyl-OHfromoneandHydrogen-Hfrom anothermonomer)betweenbuildingblocks,youcanlinkmonomersorbuilding blockstomakealargermolecule(polymer).Thisiscalleddehydration synthesis.Energyisrequired(endergonic) Byaddingawatermolecule,youcancutthelargerpolymerintoitsindividual monomersorbuildingblockcomponents.Thisiscalledhydrolysis(watercutting). Energyisgivenoff(exergonic) 13.Knowthedifferencebetweenglycogenandcellulose Glucoseconvertstoalong-chaincarbohydrate,Glycogen,tostoreintheliver,in animals. Glucoseconvertsintoalong-chaincarbohydrate,cellulose,tostoreinthecellwalls ofplantsthatgiveitstructuralsupport. 14.Explainwhyfatsandoilsareinsolubleinwater Bothfatsandoilsarehydrophobic.Thatis,theydonotattractwatersincethereis no–or+end.Theyarenon-polar. 15.Whatisthedifferencebetweensaturatedandunsaturatedfattyacids? Saturatedfatscontainnodoublebondsbetweenthecarbonsinthechainofthefatty acid. Unsaturatedfatscontaindoublebondsbetweenthecarbons.Theyarefluidasa resultofthespacecreatedbetweenthechainsduetothekinkswherethedouble bondsare. 16.Distinguishbetweenphospholipidsandtriglycerides Triglycerideshaveaglycerolbackboneandthreefattyacidchainsattached(FAT) PhospholipidshaveaglycerolbackboneandTWOfattyacidchainsandaphosphate group 17.Whatarewaxes?Whataresteroids? Waxes:lipidsthatprotectfromwater(plants,ears)andenergystorageinplankton; longchainfattyacidattachedtoanalcohol,solidatroomtemperature Steroids:lipidsthatarefusedcarbonringsthatcanbehormones(chemical messengersinthebody)orstructuralunits(cholesterolisapartofthecell membrane) 18.Beabletodrawandlabelthepartsofthephospholipidbilayer Lipids: Structure • Phospholipid—component of cell membranes Polar Head Glycerol Hydrophilic Fatty Acid Tails Hydrophobic 19.Knowthedifferenttestsonecanusetodetermineifthereisapresenceof proteins,simplesugarsorcomplexsugars(LAB) +forSimplesugars(likeglucose):benedict’ssolution(turnsfrompeacockblueto orangeorbrickred) +forComplexsugars(likestarch):Lugol’sIODINE(orange)turnsthesubstance black +forProteins(likemeat):Biuret’ssolutionturnsviolet 20. Give three examples of proteins composed of amino acids and describe the function of each. Keratin-structural support in nails Muscle (actin and myosin) for movement Collagen-maintains the elasticity of skin Hemoglobin-a protein in red blood cells that carries oxygen to tissues Dothesequestions: Multiplechoicequestions#1-39justthenumberandletteranswer(do correctionsafterwardsinadifferentcolourandexplainthecorrection) ShortAnswerquestions:#43,44,46,47,49,51-54,55-57,59,60,62,63,68, 72,77,79,81(docorrectionsafterwardsinadifferentcolourandexplainthe correction) Note:#19,insulinisaproteinandthereforehasaminogroupswithN Short Answer questions 43) The strong acid hydrogen chloride can be dissolved in water. The pH will decrease and cause the solution to be more acidic due to the release of hydrogen ions. 44) Bond X is a hydrogen bond. 46) Functions: acts as a solvent by dissolving substances, acts as a lubricant by lubricating joints, acts as a temperature regulator for body heat. 47) The electronegativity of the covalent bond causes the shared electron pair to spend more time around the nucleus of the oxygen atom than that of the hydrogen atom in a water molecule. This creates a slightly negative charge on the oxygen atom and slightly positive charges on the hydrogen atoms resulting in an unequal sharing of electrons and a polar covalent bond. 49) Runners eat meals with large quantities of carbohydrates a few days before a marathon because it provides quick fuel and short-term energy storage. The body will store the carbohydrates needed for the race and on the day of the race, glycogen will be converted into glucose so that glucose can be used to produce ATP during cellular respiration. 51) Dehydration synthesis is illustrated in the diagram. It shows the removal of a hydroxyl group of one amino acid and the hydrogen atom of the second amino acid, the equivalent of water, to allow the combining of the two into a dipeptide. 52) Bond X is a peptide bond. 53) A dipeptide and a water molecule will form as a result of this reaction. 54) 9 molecules of water will be produced if 10 amino acids are linked 55) Lactose is classified as a disaccharide that belongs to the carbohydrate family. 56) Water is required. 57) Hydrolysis is illustrated in the diagram. 59) a. The base sequences of specific sections of DNA contain a code that specifies the sequence of amino acids in the proteins of the cell. b. Nucleic acids are polymers of nucleotide monomers. c. A monosaccharide only has one sugar molecule whereas a polysaccharide contains many sugar molecules. d. A polypeptide is made up of amino acids joined together by peptide bonds. e. In the secondary structure of a protein, hydrogen bonding between the amino acids causes the polypeptide to form an alpha helix or a beta pleated sheet. f. The polarity in water molecules allows it stick together or cohesion to occur. Unequal sharing of electrons in water. 60) a. A glycerol has three carbon atoms, each of which has a hydroxyl (-OH) group bound to it. b. A triglyceride has three fatty acids attached to glycerol whereas a phospholipid has a phosphate group that replaces one of the fatty acids. c. A peptide bond forms between carboxyl group and the nitrogen of the amino group in a dipeptide. A hydrogen bond forms between different amino acids in the polypeptide chain. d. An unsaturated fatty acid has a double bond meaning it has one less hydrogen atom than a saturated fatty acid. 62) The positive result of both the disaccharide maltose and the monosaccharide glucose means there is a presence of sugar. It must have been positive because the monosaccharide glucose makes up maltose when two combine. 63) When a mixture of phospholipids and water is shaken, the phospholipids spontaneously assemble in vesicles surrounded by a lipid bilayer because the their polar heads are hydrophilic and their non polar tails are hydrophobic. 68) This is a change in the primary structure of the polypeptide chain as this is where a certain orientation is taken on. The hydrogen bonding between the altered sequence of amino acids will change the shape causing the tertiary and quaternary to also be affected as these are later stages in the protein organization where more bonding occurs. 72) Proteins are more structurally and functionally diverse than carbohydrates because the variety in its R group allows for a uniqueness in each amino acid. 77) CELLULOSE STARCH GLYCOGEN Monomer Glucose Glucose Glucose Description of Structure No side chains Less side chains More side branches (chains of glucose) that branch off from the main chain than starch Plant or Animal Cell plant plant animal Function Structural support in plants Long term storage in plants Long term storage in animals Characteristic DNA RNA PROTEIN Polymer? Yes Yes Yes 3-D Structure? Yes Yes Yes Contain nitrogen atoms? Yes Yes Yes Phosphorus atoms? Yes Yes No Hydrogen bonding? Yes No - YES Yes 79) 81) Protein organization bonding: a. primary – peptide bonds b. secondary – hydrogen bonding c. tertiary – covalent bonding, ionic bonding, H bonding and hydrophilic parts of proteins face outwards d. quaternary – bond between 2 or more polypeptides