Sec 4 2024 Biology Worksheet Answers

CELLS A–cellplasmamembraneB–centriolesC–golgiapparatusD–roughendoplasmicreticulum

A–flagellumC–peptidoglycancellwallD–chromosomeB–mesosome:locationofenzymesassociatedwithaerobicrespirationC– peptidoglycancell wall: maintainsshape/givestructure/provideturgidityE–starchgranules:storageofcarbohydrates Ribosomes:siteofproteinsynthesis

Mitochondria:releaseenergyasATPRBC: transport O ₂ through body, biconcave discshapeincreaseSA:VforefficientdiffusionofO ₂intoandoutofitRoothaircell:longandnarrowprotrusionincreasesSA:Vforefficientabsorptionofwateranddissolvedmineralsalts Plant cell: presence of chloroplast, large centralvacuole,cellulosecellwallA:ChloroplastB:NucleusC:Vacuole

A:cellplasmamembraneC:mitochondrionF:Golgiapparatus/smoothendoplasmicreticulumH:nuclearpore

Phospholipid bilayer: each layer consisting ofhydrophilic phosphate groups on theexterior andhydrophobichydrocarbonchainsoffattyacidsintheinteriorMembrane proteins (channel andcarrier proteins)arefoundinthephospholipidbilayerFluid=phospholipidmoleculesmoveaboutintheplaneofthemembraneMosaic = membrane proteins are scatteredrandomlythroughoutthephospholipidbilayerSecretorycell:PresenceofroughERthatproducespolypeptides,Golgiapparatuschemicallymodifiesandrepackagesproteins in secretory vesicles, and numerousmitochondriareleaseenergyintheformofATPforexocytosis.Bacteriaobtainnutrientseitherasaparasiteorasasaprotroph.parasite–derivesnutrientsfromcytoplasmoflivingcellsSaprophyte – derives nutrients from dead anddecayingorganicmatter(decomposition)Conditionsprovidedtoallowbacteriatoreproducerapidly:

suitable temperature, optimal pH, nutrients,moisture,availabilityofoxygen(forsomebacteria)

MOVEMENTOFSUBSTANCES ENZYMEEnzymescatalysereactionsbetweenreactants.Tempincreasetooptimum→kineticenergyofenzyme&andsubstrateincrease→rateofeffectivecollisions&enzyme-substratecomplexformationincreaseTempincreaseoveroptimum→thermalagitationbreaksnon-covalentbondsstabilising3Dconformationofactivesite→distorted→not

complementarytosubstrateshape→denaturedenzyme Concentration of enzyme & substrat, pH, andtemperatureaffectsrateofrxn Competitiveinhibitorswithstructuralresemblancetosubstratefitintoactivesitesofenzymesandblockentranceofsubstrate.Itsprogressivelydisplacedatactivesitebysubstrate. PLANTNUTRITIONSugarlevel:daylight→rateofphotosynthesis>respiration→sugarmadeinphotosynthesisDarkness→rateofphotosynthesis<respirationrate→sugarusedforrespiration Factorsaffectingphotosynthesis:Temperature,light,CO ₂ Destarchleafbyleavingentireplantindarknessfor2-3dayssothatstoragestarchisconvertedtosugarsandusedinrespiration.Starchdetectedat

theendoftheexperimentisonlyfromresultsofphotosynthesis Palisademesophylllayertightlypackedattopofleaf→maxabsorptionoflightenergybychlorophyll→maxphotosynthesisrate Spongymesophyllmanyairspaces→facilitatediffusionofcarbondioxideintoleafcellsforphotosynthesis Lightintensityincrease→higherrateofphotolysisofwater→higherrateofoxygenrelease→higherrateofproductionofATPandNADPH→higherrateofreducti