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In the light dependent reaction, solar energy is captured
by pigments in the thylakoid membrane in the
chloroplasts and used to attach phosphate groups to
energy-carrying molecules like ATP.
Previously, we learned that photosynthesis
takes place in the chloroplasts
A QUICK PSN REVIEW
In the CALVIN CYCLE, the ATP and NADPH made in the light dependent reaction are used to power the assembly of sugars in the stroma,
the fluid-filled interior of the chloroplasts.
This completes the equation for photosynthesis:
6 CO2 + 6 H20 C6H12O6 + 6 O2
So now we have energy stored in the form of
sugars. Very nice, but what if plants (or, for that
matter, people) want to release that energy?
THEY MUST USE A DIFFERENT PATH….
RETAKE QUIZ TOMORROW
CELLULAR RESPIRATION
HARVESTING CHEMICAL ENERGY
ATP
CELLULAR RESPIRATION (RSP)
Next, we’ll need another organelle to do these
reactions in! Not chloroplasts this time, but
instead another organelle with its own DNA….
FIRST, WE REVERSE THE EQUATION:6 CO2 + 6 H20 C6H12O6 + 6 O2
MITOCHONDRIA:
CELLULAR RESPIRATION:HARVESTING ENERGY FROM FOOD
The “Furnace” for making energymitochondria
Fuel food: carbohydrates, fats, proteins
HelpersOxygen enzymes
ProductATP
Waste productscarbon dioxidewater
O2
food
ATP
enzymes
CO2 H2O
MITOCHONDRIA ARE IN
animal cells plant cells
3 STAGE PROCESS
STAGE 1:
GLYCOLYSIS •Break a sugar into 2 pyruvic acids• Small 3 Carbon chunks easier to use
•Happens in cytoplasm•Net 2 ATP gain•Make NADH • Energy storage
•NO O2 needed
STAGE 2:
KREBS CYCLE
•Break pyruvic acid into CO2 releasing ENERGY
•Happens in matrix•Net 2 ATP gain•Make NADH •O2 needed
STAGE 3:
ELECTRON TRANSPORT
CHAIN•Uses high energy electrons from Glycolysis and Krebs Cycle to change ADP to ATP
TOTAL ENERGY
Glycolysis, in cytoplasm, no O2
Krebs Cycle, in matrix, with O2
Electron transport chain, with O2
2 ATP
2 ATP
32 ATP
36 ATP per 1 molecule Sugar
ATP + CO2 + H2O (+ heat)
OUR CELLS NEED TO RELEASE ENERGY SLOWLY
ATP
aerobic respirationmaking ATP energy (& some heat) by burning fuels in many small steps
Food (carbohydrates)
O2
make energy
A BODY’S ENERGY BUDGET
eatfood
synthesis(building)
• energy needed even at rest
• activity• temperature
control{
• growth• reproduction• repair{
storage• glycogen
(animal starch)• fat{
ATP
1
2
3
Can’t store ATP too unstable only used in cell
that produces it only short term
energy storage carbohydrates & fats are long term energy storage
USING ATP TO DO WORK
A working muscle recycles over 10 million ATPs per second
ATP
ADP
work
Adenosine DiPhosphate
Adenosine TriPhosphate
ATP already in muscles quickly used upATP produced by cellular respiration (more ATP, but
not made fast enough)
QUICK ENERGY -90 SEC
Any sustained exercise depends almost solely upon cellular respiration. Even elite distance runners have to pace themselves to
keep their supply of oxygen high enough.
Will change over to anerobic respiration to keep up with energy demands
ENERGY +90SEC TO 20MIN
Start breaking down fats for energy.
ENERGY+20 MINUTES
WHAT IF OXYGEN IS MISSING?
No oxygen available = can’t complete aerobic respiration
Anaerobic respirationalso known as fermentation
alcohol fermentationlactic acid fermentation
no oxygen or no mitochondria (bacteria)
can only make very little ATP
large animals cannot survive
O2
yeast
bacteria
ANAEROBIC RESPIRATIONAKA FERMENTATION
alcohol fermentationyeast
glucose ATP + CO2+ alcoholmake beer, wine, bread
lactic acid fermentationbacteria, animals
glucose ATP + lactic acidanimals feel muscle fatigueOrganisms change our food
O2
FERMENATION
Aerobic? With oxygen What part(s) of the cellular respiration pathway is (are)
aerobic? Krebs Cycle and Electron Transport Chain Why Krebs Cycle?
Anaerobic? Without oxygen What part of the cellular respiration pathway is anaerobic? Glycolysis
Can happen without oxygen
ANAEROBIC VERSUS AEROBIC
STANDARDS:
“The gradual combustion of carbon-containing compounds within cells, called cellular
respiration, provides the primary energy source of living organisms”
“Students know that in both plants and animals,
mitochondria make stored
chemical bond energy available to cells
by completing the breakdown of glucose to carbon dioxide!”
Write and label the cellular respiration equation to show where the product or reactant is being used or produced.
G = glycolysis KC = Krebs Cycle ETC = Electron Transport Chain.
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy
OPENER 2/25 – PG. 119