Download respiration - Learn Biology

GCSE Biology Week 5:
Cellular Respiration
B2 2.1 Respiration releases energy
B2 2.4 Aerobic respiration uses oxygen to release energy
from glucose
B2 2.9 Anaerobic respiration releases energy from glucose
B2 2.10 Anaerobic respiration releases less energy than
aerobic respiration
B2 2.11 A build-up of lactic acid requires extra oxygen to
break it down
AlllivingcellscarryoutRespiration– EVEN
Plants!(Theyphotosynthesize– whenits
light,andrespirewhenitsdark!)
Respirationisnotbreathing!Breathingis
ventilation (breathinginandout)which
actuallyprovidestheOxygen(O2)
neededforaerobicrespiration.
Respirationtakesplaceinthecytoplasm
&Mitochondria (rememberwhen
labellingyourcellsmitochondriaarethe
organellesthatproduceenergy!)
*sidenote– youdon’tneedto“revise”
this– butitisusefultoknow…
mitochondriaactuallyhaveinfolding’s
(calledcristae)thatincreasetheirsurface
area!
Whatdoesanincreasedsurfacearedo?
Itincreasestherateofdiffusion!
Cellular Respiration:
You need ENERGY to live.
Energy comes from the digested
chemicals from foods – respiration is the
process that releases the energy.
It is actually a process that
occurs in all your
CELLS in your body!
It is the process of
RELEASING ENERGY from
GLUCOSE.
Respiration is
NOT
BREATHING!
(ventilation)
There are 2 types of
RESPIRATION:
1. Aerobic – requires Oxygen!
Aerobic means “with O2” and aerobic respiration
occurs when there is lots of O2 present
2. Anaerobic – does not require
Oxygen!
2. Aerobic respiration releases more ENERGY
per molecule of GLUCOSE than anaerobic
respiration.
REMEMBER:
RESPIRATION is the
process of
RELEASING
ENERGY from
GLUCOSE
Mostly you are using AEROBIC
RESPIRATION:
turning GLUCOSE from your
food, and O2 from your LUNGS
into CARBON DIOXIDE and
WATER. Releasing LOTS of
ENERGY in the process!
You MUST
REMEMBER
THIS
EQUATION!
C6H12O6 + O2 à CO2 + H2O + ENERGY (ATP)
AerobicRespirationRecap.
Aerobicrespiration usesoxygen (O2)andthemostefficientwayofgetting
energy (ATP)fromglucose.
Infact,ifwecomparetoanaerobicrespiration,wefindthatforevery1molecule
ofGlucose(C6H12O6)aerobicrespiration (withO2)provides20timesmore
energythanwouldbeproducedanaerobically(withoutO2)!
BloodtransportsO2 andGlucose(C6H12O6)(Food)toourcells,whereenzymes
(biologicalcatalyst’s)speeduptheprocessofreleasingenergy.
SoWhatistheequationforRespiration? Remember,respirationusesoxygen
andfood(glucose)togetenergy!So,wehave:Oxygen+Glucose=Energy
Now,asaresultofrespirationcarbondioxide
(CO2)isalsoproduced(ourwasteproduct)
andsomewaterisproduced(H2O).So,we
mustalsoaddtheseproductstoourequation.
MakingthefullRespirationequationlooklikethis:
Oxygen+Glucoseà Energy+Carbondioxide+Water
Nowweshouldalsobeabletowritethis
out“Chemically”,So…
O2 +C6H12O6 à Energy(ATP)+CO2 +H2O
Oxygen (O2)andGlucose (C6H12O6)aretransportedinthe
bloodstream(O2 yougetfromventilation– breathingitin)
andGlucose(C6H12O6)comesfromyourdiet.
Energy (ATP– adenosinetriphosphatethe
energymolecule)isusedformanylifeprocesses.
Carbondioxide (CO2)isthewasteproduct,andis
returnedviathebloodstreamtoyourlungs
(ventilation– Breathingitout).
Water isalsoabyproductofrespiration,whichis
thenlostassweat;someinyoururine;andsome
asmoistbreath(ventilation– youbreathout
somewater).
Thisiswhatisgoingon
1. ATP is the ‘ENERGY CURRENCY’
of living things…
2. ATP is a small molecule
that is easily transported
around cells. It carries the
ENERGY released during
RESPIRATION to the places
where ENERGY is NEEDED
3. Energy released from both
aerobic and anaerobic
respiration is used to make
ATP
The energy released
by respiration is used
to make ATP
(adenosine
triphosphate)
Your muscles require energy (ATP)
from respiration to contract.
When you exercise some of
your muscles contract more
often, and so need more
ENERGY!
This ENERGY comes from
increased respiration!
MUSCLES NEED
ATP
This increase means you need to get more
O2 and GLUCOSE into the cells.
So… your BREATHING
RATE INCREASES to
get more O2 into the…
Blood.
BREATHING
RATE
INCREASES!
Your HEART RATE
INCREASES to get
GLUCOSE and
OXYGENATED
BLOOD around the
body supplying your
muscles quickly, and
removes CO2 quickly at
the same time!
HEART
RATE
INCREASES
How much you RESPIRE is dependent upon what you are doing!
e.g. you respire more when doing exercise…
ANAEROBIC RESPIRATION:
When you do vigorous
exercise your body cannot
supply enough O2 to your
muscles using anaerobic
respiration – even though
your Heart rate and
breathing rate increase as
a much as possible!
Does NOT
use O2 at all!
So, your muscles start to respire
without O2 – they respire
anaerobically.
(in addition to aerobic)
ANAEROBIC
simply means
‘without O2’.
It is NOT the best way to use
GLUCOSE because it releases
much LESS ENERGY.
ANAEROBIC =
‘without O2’.
During anaerobic
respiration GLUCOSE
is only PARTIALLY
broken down and
LACTIC ACID
is also produced!
You MUST
REMEMBER
THIS
EQUATION!
GLUCOSE à LACTIC ACID (+ ENERGY RELEASED)
The ADVANTAGE is
that you can continue using
your muscles!
However… The LACTIC
ACID produced can build up
in the muscles.
Oxygen Dept
This is why you continue to have an
increased BREATHING RATE for a while
after you have stopped Exercising.
After resorting to
anaerobic respiration, your
muscles have an O2 DEPT.
This is the amount of
extra O2 required to break
down the built up
LACTIC ACID.
The Lactic acid is BROKEN
DOWN in your MUSCLES and in
your LIVER…
…so
your
HEART
RATE has
to remain
HIGH to carry
The EXTRA
required to
Break the LACTIC ACID down.
AnaerobicRespirationRecap.
Anaerobic=withoutoxygen(O2)
Sometimesweneedtoproduceenergyveryquickly– i.e.explosiveactivitieslikesprinting.
So,anaerobicrespirationtakesplacewhenthereisn’tenoughoxygen(O2)availabletosupplythe
body(e.g.muscles)withtheO2 requiredfor‘normal’aerobicrespiration.
Anaerobicrespirationisveryusefulinemergencies!(thinkFightorFlight– whichwe’llcover
whenwecoverthenervoussystem).Onthewhole,anaerobicrespirationdoesnotproducesas
muchenergyasaerobicrespiration(about20timeslessremember)butisveryrapid.Thisis
becauseglucose(C6H12O6)isonlypartiallybrokendown.
Whenglucoseisonlypartiallybrokendownanotherwasteproductismade– Lacticacid!
Wecanshowthiswithour“wordequation”forAnaerobicrespiration:
Glucoseà Lacticacid+Energy(ATP)
Thisiswhat’sisgoingon…
Glucose (C6H12O6) isdeliveredtothecells(muscles)viathebloodstream.
Lacticacid isawasteproduct(thatbuildsupinthemuscles– andleadsto
“cramp”)
Energy(ATP) onlyasmallamountisproduced– butisenoughforshortterm/
explosiveactivity.
Abuildupoflacticacidrequiresextra
oxygentobreakitdown.
Asyouincreasephysicalactivity
(exercise)yourbreathing
(ventilation)ratewillalso
increase.Thisisbecauseyour
cells(yourbody)needsthe
extraoxygeninordertorespire
(carryoutaerobicrespiration)
efficiently,andprovidethe
extraenergyneeded.
So,asyourbreathing(ventilation)
rateincreaseslargeramountsofO2
entersyourbloodstream,yourheart
mustaccommodatebyspeedingup,
andsupplyingthisoxygenated
bloodtoallthecellsandtissues
thatrequireit.
Thequickeryoubreathe,thequickeryourheartrate!
ThissuppliesO2 whereneeded,butastherateof
respirationisincreasedsoarethewasteproducts.
Todealwiththistherateofdiffusionof(O2 andCO2)atthe
Alveoli(inthelungs)andattheMusclecellsincreases.
(Rememberthesegasesaremovingdowntheir
concentrationgradients).
However,thisincreaseddiffusionandsupplyofO2 /removalof
waste(CarbondioxideCO2)cannotgoonindefinitely.Asyou
performvigorousexercises(likeInsanity,Tapoutorsprintingaway
fromcrocodiles)yourbodyisunabletosupplyalltheO2 needed/
quicklyenough.
So,yourcellsstarttorespireanaerobically!(but
rememberthiscomeswithitsownwasteproduct–
Lacticacid).Theupsideisthatyoucancarryon
exercisingandusingthosemusclesalittlebitlonger!
Becauseyourbreathingrate
hasincreasedandyouhave
employedanaerobic
respirationyouwillbe“out
ofbreath”!Thisiscalled
oxygendept.
Afterallthiscrazyexerciseyou’ll
mostlikelybe“outofbreath”!
So,youwillhavetorepaytheO2dept.– which
iswhyyoubreatheheavilyfollowingvigorous
exercise.Thisisgiveaspecialacronym:
EPOC
Exercise/post-exerciseoxygenconsumption.
Thismeansyou’llcontinuetobreathe
heavily– takinginlotsofO2 intothe
bloodstream,supplyingthecellsand
muscles.Yourheartratewillremainhigh
todealwiththisextraO2demand.The
extraO2 isusedtoconvertLacticacidinto
CO2 andH2O– whereyoubreathethem
out(andsweatthemout– H2O).
*Whenwecoverthecirculatorysystems
andrespiratorysystemswewill
investigatetheeffectsofexercise,so,
howcellularrespiration– i.e.howcells
gettheirenergyandutiliseitwillbe
revisited. You will also need to remember
to connect cellular respiration with
Diffusion and active transport!
Question
time…