photosynthesis and cellular respiration
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Photosynthesis and Cellular Respiration. Photosynthesis in nature. According to the way they obtain energy, all living things can be divided into : Autotrophs : producers ; obtains organic food without eating other organisms - PowerPoint PPT PresentationTRANSCRIPT
Photosynthesis and Cellular Respiration
Photosynthesis in nature According to the way they obtain energy, all living things
can be divided into : Autotrophs: producers; obtains organic food without
eating other organisms Heterotrophs: consumers; obtains organic food by eating
other organisms or their by-products (includes decomposers)
How are they connected?
glucose + oxygen carbon + water + energydioxide
C6H12O6 6O2 6CO2 6H2O ATP+ + +
Heterotrophs
+ water + energy glucose + oxygencarbondioxide
6CO2 6H2O C6H12O6 6O2lightenergy
+ ++
Autotrophsmaking energy & organic molecules from light energy
making energy & organic molecules from ingesting organic molecules
Where’s the ATP?
oxidation = exergonic
reduction = endergonic
NPK
…
H2O
What does it mean to be a plplantant• Need to…
– collect light energy
– store light energy
– need to get building block atoms from the environment • C,H,O,N,P,K,S,Mg
– produce all organic molecules needed for growth• carbohydrates, proteins, lipids, nucleic acids
ATP
glucose
CO2
The chloroplast
Sites of photosynthesis Pigment: chlorophyll Plant cell: mesophyll Gas exchange: stomata Double membrane Thylakoids, stack-granum Stroma-fluid-filled interior
Photosynthesis
• Light reactions– light-dependent reactions– energy conversion reactions
• convert solar energy to chemical energy
• Calvin cycle– light-independent reactions– sugar building reactions
• uses chemical energy (ATP) to synthesize glucose (C6H12O6)
It’s not theDark Reactions!
Light reactions• Convert solar energy to chemical energy
– ATP
– NADPH
• What can we do now?
energy
reducing power
build stuff !!
photosynthesis
ATP
The Calvin CycleWhoops! Wrong Calvin…1950s | 1961
How is that helpful?• Want to make C6H12O6
– synthesis– How? From what?
What raw materials are available?
CO2
C6H12O6
NADPH
NADPreduces CO2carbon fixation
NADP
RuBisCo • Enzyme which fixes carbon from air
– ribulose bisphosphate carboxylase – the most important enzyme in the world!
• it makes life out of air!
– definitely the most abundant enzyme
I’m green with envy!
It’s not easy being green!
Putting it all together
CO2 H2O C6H12O6 O2lightenergy + ++
SugarBuildingReactions
Energy BuildingReactions
Plants make both: energy
ATP & NADPH sugars
sunlight
O2
H2O
sugars
CO2
ADP
ATP
NADPH
NADP
H2O
Energy cycle
Photosynthesis
Cellular Respiration
sun
glucose O2CO2
plants
animals, plants
ATPThe Great Circleof Life,Mufasa!
CO2 H2O C6H12O6 O2lightenergy + ++
even thoughthis equationis a bit of a lie…it makes a better story
CO2 H2OC6H12O6 O2ATPenergy+ ++
2007-2008
You can grow if you Ask Questions!
2006-2007
What’s thepoint?
The pointis to makeATP!
ATP
Cell Respiration
What is Cell Respiration? • A series of reactions that break down molecules to produce
energy – OR the catabolism of glucose to produce ATP
C6H12O6 6O2 ATP 6H2O 6CO2+ + +
CO2 + H2O + heatfuel(carbohydrates)
COMBUSTION = making a lot of heat, energy by burning fuels in one step
RESPIRATION = making ATP (& some heat)by burning fuels in many small steps
CO2 + H2O + ATP (+ heat)
ATP
glucose
glucose + oxygen energy + water + carbondioxide
resp
irati
on
O2 O2
+ heat
enzymesATP
The reactions are called REDOX Oxidation & reduction
• Oxidation– adding O– removing H – releases energy– exotermic
• Reduction– removing O– adding H – stores energy– endotermic
C6H12O6 6O2 6CO2 6H2O ATP+ + +
oxidation
reduction
(1)Glycolysis • Breaking down glucose
– “glyco – lysis” (splitting sugar)
– but it’s inefficient
• generate only 2 ATP for every 1 glucose
– occurs in cytoplasm
glucose pyruvate2x6C 3C
In thecytoplasm?Why doesthat makeevolutionarysense?
That’s not enoughATP for me!
Is that all there is?• Not a lot of energy…
– for 1 billon years+ this is how life on Earth survived• no O2 = slow growth, slow reproduction
• only harvest 3.5% of energy stored in glucose– more carbons to strip off = more energy to harvest
Hard wayto makea living!
O2
O2
O2
O2
O2
glucose pyruvate
6C 2x 3C
NADH
pyruvate
acetyl-CoA
lactate
ethanol
NAD+
NAD+
NADH
NAD+
NADH
CO2
acetaldehyde
H2O
Krebscycle
O2
lactic acidfermentation
with oxygenaerobic respiration
without oxygenanaerobic respiration“fermentation”
How many types of Cell Respiration?
which path you use depends on who you are…
which path you use depends on who you are…
alcoholfermentation
Fermentation (anaerobic)• Bacteria, yeast
1C3C 2Cpyruvate ethanol + CO2
Animals, some fungi
pyruvate lactic acid3C 3C
beer, wine, bread
cheese, anaerobic exercise (no O2)
NADH NAD+
NADH NAD+
back to glycolysis
back to glycolysis
recycleNADH
Alcohol Fermentation
1C3C 2C
pyruvate ethanol + CO2
NADH NAD+
Count thecarbons!
Dead end process at ~12% ethanol, kills yeast can’t reverse the reaction Generates only 2 ATP!
bacteria yeast
back to glycolysis
recycleNADH
Reversible process once O2 is available, lactate is converted back to
pyruvate by the liver Generates only 2 ATP
Lactic Acid Fermentation
pyruvate lactic acid3C 3C
NADH NAD+
Count thecarbons!
O2
animalssome fungi
back to glycolysis
Pyruvate is a branching pointPyruvate
O2O2
mitochondriaKrebs cycleaerobic respiration
fermentationanaerobicrespiration
ATP accounting so far…• Glycolysis 2 ATP
• Kreb’s cycle 2 ATP
A working muscle recycles over 10 million ATPs per second
There’s got to be a better way!
I need a lotmore ATP!
It is called ELECTRON TRANSPORT CHAIN and makes LOTS of ATP !!!
Counting the energy released in AEROBIC RESPIRATION
• Glycolysis brings : 2 ATP • Kreb’s Cycle brings: 2 ATP)• Electron transport brings: • From glycolysis = 6ATP • From acetyl CoA = 6ATP
From Kreb’s cycle = 22 ATP
• 38 TOTAL ATP/one molecule of glucose