-
B2revision
1
May22,2012
DNAmolecule
FirstdescribedbyWatson&Crickin1953 DoubleStranded
Twistedintoahelix(spiral) SugarPhosphatebackbone
Complimentarypairingofbases
Adenine=ThymineCytosine=Guanine
SectionsofDNAcontaingenesresponsibleforproducingproteins
ProteinSynthesis
2stageprocess!
Transcription(transcribe/copy) DNAstrandunwinds
complimentarymRNAstrandmade mRNAleavesthoughthenuclearpore
Translation(translate) mRNAattachestoribosome
attractstRNAmoleculesshowingtripletcodons
tRNAcodonsstickspecificaminoacidstogetherTripletCode(3bases)controlorderofaminoacids
makesapolypeptidechain
-
B2revision
2
May22,2012
-
B2revision
3
May22,2012
Microorganisms
Canbeusedtoproducehumaninsulin Moreeffectivethanpiginsulin
Doesnotcauseallergicreactionsinpatients
-
B2revision
4
May22,2012
Advantages
Widerangeofproductse.g.humaninsulin,medicines,beer
Canbeusedtogrowmycoproteinse.g.quorn Quickandefficient
easytokeepandmanipulate cangrowanywherei.e.notclimatedependent
canusewasteproductsfromotherindustriese.g.quornusingwastefromflour
Disadvantages
optimumconditionsrequiredformostefficientgrowth
lowriskofcontamination humanviewsoneatingmicroorganisms
RespirationTheprocessbywhichcellsreleaseenergyfromglucose
AerobicInthepresenceofoxygen
glucose+oxygen carbon+water+energydioxide
glucosedigestionoxygenlungsviathebloodcarbondioxideremovedbyblood
Usesofenergy: temperaturecontrol musclemovement
sendingnerveimpulses transportaroundthebody growthandrepair
absorbingfood
Occursinmitochondria Largesurfacearea
Mitochondriamakeadenosinetriphosphate(ATP)
Actsasastoreofenergythatcanbereleasedinstantly
-
B2revision
5
May22,2012
Exerciseandrespiration
AnaerobicRespiration
Thepointatwhichyourheartcannolongersupplythemusclesfastenough.
glucose lacticacid+energy
Doesnotproducemuchenergy(0.8kJ/gcomparedwith16.1kJ/ginaerobic)
Lacticacidisapoisoncausescramp
OxygenDebt
Theamountofextraoxygenneeded(postexercise)tobreakdownanylacticacidbuildup.
Yeastcanrespireanaerobicallyandareusedtoproducebeerandwine
glucose ethanol+carbon+energydioxide
FadDiets
17%of15yearoldsareobese!
Fadfashionableadvicewithnoscientificevidence
BodyMassIndex(BMI)canbeusedtoworkoutifyouareoverweightorobese
BMI=mass(kg)height2(m)
Exceptionstotherule: pregnantwomen children
professionalsportsmen/women
Atkins
HighproteinverylowcarbohydrateLessinsulinproducedthereforelessfatstorageanduseofalreadystoredfatforenergyIncreasedriskofcancerfromeatinghighlevelsofproteinProductionofketonesmaydamageliver
Usedietbooks,magazinesandtheinternettoresearchsomeotherdietsandexplainhowtheyaresupposedtowork
Dangers Riskofheartdisease/heartattacks Diabetes
Strainonjoints
-
B2revision
6
May22,2012
Whatisgrowth?
AnincreaseinsizeorweightOrganismsofthesamespeciescanveryinsizeSomeanimalsareabletoregeneratee.g.starfish,gecko
Growthfactorscanbeusedtoenhanceperformance
Lookupexamplesofhowtheseworkandthereasonsbehindbanningthem.Whatsideeffectsdotheyhave?
-
B2revision
7
May22,2012
Growthdependsupon:
DifferentiationStemcellsbecomingothertypesofcelle.gskin,bone,blood,nerve
ElongationCellsgrowinsizeandlengthe.g.plantcells
CellDivisionmakingmanycopiesofcellstoallowfortissueconstruction
Genesinheritedfrommotherandfather
Hormoneshumangrowthhormone(hgh)plantauxins
Dietnutritiontoallowsubstratesforgrowth
Mitosiscelldivision
-
B2revision
8
May22,2012
MeiosisProductionofgametes
-
B2revision
9
May22,2012
Providescellsforgrowthandrepair
Createsgametes
Daughtercellsaregeneticallyidentical
Fourdaughtercells
Daughtercellsarediploid
mitosis meiosis
-
B2revision
10
May22,2012
Summarisetheviewsofpeoplewhoarefororagainstlegalinducedabortion.
Useevidencetodecidewhetherthelawshouldbechangedornot.Givereasonsforyouranswer
-
B2revision
11
May22,2012
Explorethescientificevidenceregardingtheageandlegalityoftermination
pregnancyupto24weekscanbeterminated
24weeksisthepointatwhichababycansurvivewithoutmedicalintervention
canbelaterifthemotherorbabyisatrisk 2doctorsmustagree
Pros
Womenfeelliketheyhaveachoice Riskstomotherreduced
Optionstoterminatedisabledoffspring Reducesunwantedbabies
Lessstrainonadoption/children'sservices/benefits Rape
Ageofmother
Cons
Religionbeliefinthesanctityoflife Seenasaformofcontraception
Notequalresponsibilityindecisionmaking
Possibilityoffuturecomplicationinconceiving
Foetusisabletosurviveoutsidethewombat20weeks Costsmoney
PlantGrowth
Howdoplantsgrow?(Whatdotheyneedtogrow)Howdotheyknowwhichwaytogrow?Howcouldwetestthis?
Canwetrickaseedintogrowingupsidedown?
Canweturnmustardgay?
-
B2revision
12
May22,2012
PlantResponsesTropisms
Alllivingorganismsaresensitivetochangesintheirsurroundings.
Plantsaresensitivetolight,moistureandgravity.
Theresponsetolightiscalledphototropism.Theresponsetogravityiscalledgeotropism.Theresponsetomoistureiscalledhydrotropism.
Shootsgrowupwardstowardslightandagainsttheforceofgravity.Rootsgrowdownwardstowardsmoistureandinthedirectionoftheforceofgravity.
Hormones
Thewaysinwhichaplantrespondstothesestimuliiscoordinatedbyhormones.
Hormonesalsocontrolthegrowthofaplant. Oneplanthormoneiscalledauxin.
Auxinismadebycellsinthetipsoftherootsandshoots.
Itspeedsupgrowthinshootsandslowsdowngrowthinroots.
Unequaldistributionofhormonescausesunequalgrowthratesindifferenttissues.
-
B2revision
13
May22,2012
-
B2revision
14
May22,2012
CommercialUsesofHormones
Rootingpowdercontainsauxin.Itisappliedtocuttingstostimulatethegrowthofroots.Largenumbersofplantscanbeproducedquickly,somoremoneycanbemade.
Hormonescontrolfruitripening.Producersusechemicalstoslowdowntheripeningoffruits,suchasbananas,duringtransport.Justbeforesale,ripeningcanthenbespeededupusingdifferentchemicalsandawarmertemperatureinthestorerooms.
Weedkillerscontainsynthetichormonesthatstimulatetheplantstogrowveryrapidly.Theirnormalgrowthpatternsaredisrupted.Theybecometallandspindly,andeventuallydie
SeedlessFruitisproducedbysprayingartificialauxinontotheunpollinatedflowers.Thisresultsinfruitwithnopips
-
B2revision
15
May22,2012
Howdoplantsgrowinspace?
Rootsarenegativelyphototropicsoareabletogrowdownwithouttheforceofgravity
-
B2revision
16
May22,2012
SelectiveBreeding
Processbywhichhumansdevelopcrops/herdswithdesirablecharacteristics
Advantages
Improvethequalityofmilkfromcattlehighyield/%calcium
Safer?thangeneticmodification MoreacceptedthanGM
Increasedyieldofwheatbydevelopingdwarfvarieties(lessenergygoesintothestalk)
Sheepabletohavemultiplebirths
Disadvantages
Decreaseingeneticdiversityinbreeding Mightnotwork
Ethicalissuese.g.BelgianBluemusclecows Takestimeovermanygenerations
Increaseingeneticdefects/susceptibilitytodisease
-
B2revision
17
May22,2012
Cloning
IdenticalTwinsareexamplesofclonesgeneticallyidenticaltoeachother
Aspiderplantproducesnaturalclonesknownas'plantlets'ontheendofrunners
Potatoesgrowbyplantingpotatotuberswhichwillallgrowintoclonedplants
Cuttingswillalsogrowtobeidenticaltotheoriginalplant
Cloning
Farmersabletoproduceexactcopiesoftheirbestcows,sheepandpigs
Lotsandlotsofcopiescanbemade
Plantsdoitnaturallystrawberries/spider
Takeslotsofattemptstogetitright(29/277triesbegantodevelop1/29washealthy)
Highnumberofgeneticrejects
Pronetodisease
Lackofvariationcanresultinwholespeciesbeingwipedoutbydisease(potatofamineinIreland)
Dollylivedaveryshortlife'trueage'oftheoriginaluddercell
-
B2revision
18
May22,2012
GeneticModificationinplants
GeneticModification
Genesareswitchedoffe.g.'Flavrsavr'tomatoeskeepfresherforlongerwithoutgoingmushy
Switchongenese.g.GoldenRicemakesVitaminAusefulfordevelopingcountrieswithlimiteddiet
GeneTransferUsefulgenesaretransferredintoplantsand/oranimalstoproducedesirablecharacteristicse.g.maizethatcontainsessentialfattyacids
potentialbenefits
ResistancetoPESTSandHERBICIDES
ResistancetoenvironmentalfactorsDROUGHT,TEMPERATURE
Animalscapableofproducingsubstancesindemande.g.FACTOR8(usedinbloodclotting)
moralðicalissues
Unnaturaltomesswithgenes
Mayleadtounplannedproblemscrosspollination
Transferofunwantedgenestootherorganisms costtofarmers
-
B2revision
19
May22,2012
GeneTherapyAmoveforwardinmodernmedicinethatwillallowdoctorstotreatpatientswithgeneticdefects
Problems difficultyindeliveringgenetomultipleareas
somediseasescausedbygenecombinationsdifficulttoidentifyandreplacingthedefectivegenes
findingasafewaytodeliverthegene1patientdiedafterreactingviolentlytothevirusused
riskofmutation
somedefectivegenesactuallyhavehiddenbenefitssicklecell/malaria
ethicsdevelopmentofaraceofsuperhumansagainstthewillof'God'
Longtermrisksareunknown
-
B2revision
20
May22,2012
Complete the diagrams - adding notes on the functions of each
organelle
-
B2revision
21
May22,2012
Plantsandphotsynthesis
As cells develop they can become specialised to perform specific
functions in the body
Identify the specialised cells and describe their adaptations in
relation to the job that they do
-
B2revision
22
May22,2012
Osmosis
-
B2revision
23
May22,2012
ActiveTransport
Movingparticlesagainsttheconcentrationgradient(lowhigh),Energyisneededto'pay'thecarriersinthemembrane
Requiresenergyfromrespiration
Movesdissolvednitratesfromsoilintoroothaircells
Movesmineralionsagainsttheconcentrationgradient
-
B2revision
24
May22,2012
Cellsaresurroundedbymembranesthatcontrolthemovementofsubstancesintoandoutofthecell.
Sketchthecellmembraneofacell.Adddotstoyourdiagramtoshowtheparticlesofaconcentratedsolutionoutsidethecell,andofadilutesolutioninsidethecell.
Explainwhyparticlescangetintothecell.
Addnotestoyourdiagramtoshowhowtheparticlesmove.Refertothesizeoftheparticles.
Includekeywordsinyourdescriptions
Usethediagramtohelpyouwritenotestoexplainhowactivetransportoccurs.
-
B2revision
25
May22,2012
Cyanideisapoisonthatstopscellscarryingoutrespiration.Ifcyanidewasaddedtothewatersurroundingaplantsroots,describewhatwouldhappentotheplantsabilitytotakein:
awaterbmineralsalts.
Explainyouranswers.
ExtensionWhenapottedplantbecomeswaterlogged,thelevelofoxygeninthesoildropsdramatically.Whydoesthisreducetherateofmineralsaltuptake?
Foode.g.fruitandvegetables Clothinge.g.hemp/cotton Fuele.g.wood
Medicinee.g.Quinine(totreatmalaria)comesfromthebarkofacinchonatree
Buildinge.g.wood/rubber
Listsomeusesofplantsandgiveexamples
Whyareplantssoimportant?
Describethechangesinhumansocietybroughtaboutbytheinventionofagriculture
noneedtomovearoundvillagesbecamefixed foodsuppliesbecamereliable
newcraftsweredevelopedtofarmandproducefood
moneywasinventedtopayforfood
lawsandsoldierswereneededtoprotectthevaluableland
writingwasinventedtokeeprecords
-
B2revision
26
May22,2012
RootHairCell
-
B2revision
27
May22,2012
Photosynthesis
-
B2revision
28
May22,2012
Investigating photosynthesis
HypothesisThe higher the light intensity the faster the rate of
photosynthesis
elodea
sodium hydrogencarbonate solution
beaker
funnel
distanceoflampfromelodea(cm)
Numberofbubbles
producedin1minute
LimitingFactors
Alimitingfactorissomethingthatslowsdownareaction.Agroupofwalkerswillhavetogoasslowlyastheslowestwalkerhebecomesthelimitingfactor.Inthesameway,photosynthesisisaseriesofcomplexreactions.Ifoneofthesereactionsisslowthentheothersjusthavetowait.
-
B2revision
29
May22,2012
PlantsandWater
Waterisnotalimitingfactor.Aplantthatislackingwaterhasmoreimportantproblemsthanitsrateofphotosynthesis.Plantsshutdowntheirphotosyntheticequipmentintimesofwaterstress.Theeffectofwaterstressisimportantandcanreducetheyieldoftheplantevenifmorewaterisaddedlater
Whatadvicewouldyougivetoagardeneraboutwateringtomatoplants?
-
B2revision
30
May22,2012
Explainwhyveryfewplantsgrowinthearctic.Usethetermsenzymesandphotosynthesisinyouranswer
Explainwhyveryfewplantscangrowinthedeserteventhoughithasamuchhigheraveragetemperaturethanarainforest?
PhotosynthesisandCarbonDioxide
Thegraphbelowshowsthechangesincarbondioxideconcentrationmeasuredinafieldofgrassduringawarmdayinthesummer
Explaintheshapeofthegraphincludethefollowingkeyideas.Photosynthesis,respiration,temperature,lightintensity
C
O
2
c
o
n
c
e
n
t
r
a
t
i
o
n
(
p
p
m
)
time(hours)0000 0400 0800 1200 1600 2000 2400
-
B2revision
31
May22,2012
ThecarboncycleTherateofphotosynthesisdependspartlyupontemperature.Usingthecarboncyclemodel,suggesthowglobalwarmingcouldaffecttheamountofcarbondioxideintheatmosphere
-
B2revision
32
May22,2012
carboncompoundsintheatmosphere
carboncompoundsinanimals
carboncompoundsinbiogas
carboncompoundsinplants
BA
C
D
E
Copythediagramandreplacetheletterswiththecorrectlabelfromthislist:respiration,photosynthesis,decaybybacteria,burning
OutcomeUse the carbon cycle to explain why for thousands of
years the amount of carbon dioxide in the Earth's atmosphere was
approximately constant and that, during the past two hundred years,
the amount of carbon dioxide in the atmosphere has been steadily
rising.
Global Warming - do the facts stand up?
Activity
-
B2revision
33
May22,2012
Complete the task about global warming and make a decision as to
whether there is enough evidence to support the theory that the
planet is warming up due to the greenhouse effect
Global Warming
Every story has 2 sides - this includes the causes for global
warming. One side says this is a natural phenomenon whilst the
other links rises in the Earth's temperature with human emissions
of greenhouse gases.
Who's to blame?
OutcomeWeigh up the evidence for this theory, as well as that of
the opposing theory that human activity causes global warming
Activity
-
B2revision
34
May22,2012
TheoryAHumanactivity TheoryBNaturalCauses
TheNitrogenCycle
-
B2revision
35
May22,2012
NitrifyingBacteria
inthesoilcanchangeammonia(foundinanimalwasteanddecayingmatterintonitrates.
NitrogenFixingBacteria
foundinsoilandrootnodulesOxidisenitrogeninsoilairspacesintonitrates(NO3
)whichplantsarethenabletoabsorbthroughactivetransport
DenitrifyingBacteria
foundinwaterloggedsoil.ChangenitratesbackintoNitrogen
RememberLightningcausesNitrogenandOxygentocombineandformNitrateswhicharewashedintothesoilbyrain
Amountofseedproduced(kg/ha)
Area Control +fertiliser +rootnodulebacteria
A 2341 2432 2462
B 2483 2660 3119
Resultsofaninvestigationintotheeffectofusingeithernitrogenfertiliserorrootnodulebacteriaontheamountofseed
producedbyalegumecrop
Presenttheresultsinasuitablegraph.Usethegraphtohelpyoudrawaconclusionabouttheeffectsofrootnodulebacteriaontheamountofseedproduced
-
B2revision
36
May22,2012
Howdofertilisersharmtheenvironment?
Thisprocessisknownaseutrophication
Organicfarmersoftenpracticecroprotation.Theywillgrowcropplantsinafieldfortwoorthreeyears.Thenextyeartheydonotplantanycropsbutallowclovertogrowandcattletograzethefield.Explainhowthissystemhelpstokeepthesoilfertilewithouttheuseofchemicalfertilisers.
-
B2revision
37
May22,2012
Whydofarmersusefertilisercontainingnitrateontheirfields?
Readtheinformationinthebox
FishDieinMillPond
ThefishingclubhasblamedlocalfarmersforthedeathoffishinMillppond.Afisherman
-
B2revision
38
May22,2012
Problems with a rising population
http://www.worldometers.info/worldpopulation/
more roomneeded for houses-less land for farming
-
B2revision
39
May22,2012
Intensive Farming is an example of how we can maximise food
production.Explain some of the cultural, moral and ethical issues
attached to intensive farming.
-
B2revision
40
May22,2012
Use an example of a greenhouse to compare the growth of
tomatoes
Biospheresareclosed,selfregulatingsystemscontainingecosystemsincludingartificialonessuchasBiosphere2and,potentially,onesonotherplanetsormoons.
Thefollowingmustbeinbalance(usemustequalproduction)
CarbonDioxideOxygenFood
Howcouldweusetheideaofabiospheretocolonisemars.Whatthingsdoweneedtobeawareof?
-
B2revision
41
May22,2012
Indicators of Air PollutionLichens are plants that grow in
exposed places such as rocks or tree bark. They need to be very
good at absorbing water and nutrients to grow there, and rainwater
contains just enough nutrients to keep them alive. Air pollutants
dissolved in rainwater, especially sulphur dioxide, can damage
lichens, and prevent them from growing. This makes lichens natural
indicators of air pollution. For example:
Blackspot FungusAnother indicator of air quality is the
blackspot fungus on roses. Blackspot fungus grows well on roses in
unpolluted areas because it is killed by the presence of sulphur
dioxide that would be found in polluted air.
-
B2revision
42
May22,2012
-
B2revision
43
May22,2012
The diagram shows the contents of a typical household waste bin
in 1990. Since 1990 many local councils have introduced recycling
schemes
Complete the worksheet to explain why we need to recycle more
and landfill less
B2.4 7c
Reasons for recyclingH
Chart A shows how long the estimated
reserves of some non-renewable resources are expected to last on
the basis of current and predicted use.
.
1 a What does non-renewable mean?
b Write down another example of a non-renewable resource.
2 How does the evidence in chart A
support the argument for recycling?
Chart B shows the percentage energy saved by recycling materials
to make new products rather than using raw materials.
3 How is the energy produced to power the manufacture of new
products?
4 Which two materials in household waste save the most energy if
they are recycled?
5 The raw materials to make glass are plentiful and the energy
savings are low. Does it make sense to recycle glass? Explain your
answer
6 Removing ink from paper so that it can be recycled can be both
expensive and polluting. If paper is recycled to make paperboard
and packaging, it does not
need de-inking. Is it still environmentally sound to recycle
paper? Explain your answer.
7 We could reduce the problem of rubbish in other ways, such as
the following:
l Burning rubbish in incinerators generates energy that can be
used for other processes.
RESOURCE
RESOURCE
Chart A.
Chart B.
l In some European countries, food and other home products have
much less packaging than we have in the UK. Less packaging means
less to throw away.
l Doorstep delivery of milk means that the glass bottles can be
used over and over again.
Carry out research to find the advantages and disadvantages of
solving our rubbish problem in different ways. Use your research to
write notes for a short talk to answer the question Is more
recycling the only solution to the problem of our rubbish in the
UK?
128GCSE Additional Science Copymaster File Edexcel Limited
2007
ALUMINIUM
COPPER
IRON
ESTIMATED TIME UNTIL RESERVES RUN OUT (YEARS)
OIL
COAL
MAXIMUM ENERGY SAVING (%)
ALUMINIUM
GLASS
PAPERBOARD PULP
PLASTICS
STEEL
SMART Notebook
-
Attachments
Recycling.doc
B2.4 7c
Reasons for recyclingH
Chart A shows how long the estimated
reserves of some non-renewable resources are expected to last on
the basis of current and predicted use.
.
1 a What does non-renewable mean?
b Write down another example of a non-renewable resource.
2 How does the evidence in chart A
support the argument for recycling?
Chart B shows the percentage energy saved by recycling materials
to make new products rather than using raw materials.
3 How is the energy produced to power the manufacture of new
products?
4 Which two materials in household waste save the most energy if
they are recycled?
5 The raw materials to make glass are plentiful and the energy
savings are low. Does it make sense to recycle glass? Explain your
answer
6 Removing ink from paper so that it can be recycled can be both
expensive and polluting. If paper is recycled to make paperboard
and packaging, it does not
need de-inking. Is it still environmentally sound to recycle
paper? Explain your answer.
7 We could reduce the problem of rubbish in other ways, such as
the following:
l Burning rubbish in incinerators generates energy that can be
used for other processes.
RESOURCE
RESOURCE
Chart A.
Chart B.
l In some European countries, food and other home products have
much less packaging than we have in the UK. Less packaging means
less to throw away.
l Doorstep delivery of milk means that the glass bottles can be
used over and over again.
Carry out research to find the advantages and disadvantages of
solving our rubbish problem in different ways. Use your research to
write notes for a short talk to answer the question Is more
recycling the only solution to the problem of our rubbish in the
UK?
128GCSE Additional Science Copymaster File Edexcel Limited
2007
ALUMINIUM
COPPER
IRON
ESTIMATED TIME UNTIL RESERVES RUN OUT (YEARS)
OIL
COAL
MAXIMUM ENERGY SAVING (%)
ALUMINIUM
GLASS
PAPERBOARD PULP
PLASTICS
STEEL
SMART Notebook
Page 1Page 2Page 3Page 4Page 5Page 6Page 7Page 8Page 9Page
10Page 11Page 12Page 13Page 14Page 15Page 16Page 17Page 18Page
19Page 20Page 21Page 22Page 23Page 24Page 25Page 26Page 27Page
28Page 29Page 30Page 31Page 32Page 33Page 34Page 35Page 36Page
37Page 38Page 39Page 40Page 41Page 42Page 43Attachments Page 1