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