Energy FlowEnergy Flow““The Carbon Cycle”The Carbon Cycle”

Where do we get Where do we get all of our energy?all of our energy?

Directly or indirectly, almost Directly or indirectly, almost all organisms get the energy all organisms get the energy needed for metabolism from needed for metabolism from the sun. the sun.

Photoautotrophs use the Photoautotrophs use the sun’s rays to make organic sun’s rays to make organic compounds compounds These compounds store energy and These compounds store energy and

serve as food for heterotrophs)serve as food for heterotrophs)

What are What are chemoautotrophs?chemoautotrophs?

The PathThe Path

Building MoleculesBuilding Molecules

Photosynthesis – Photosynthesis – light energy is used light energy is used to build glucose – to build glucose – CC66HH1212OO66

Chemosynthesis – Chemosynthesis – chemical energy is chemical energy is used to build organic used to build organic molecules. molecules.

Breaking Down MoleculesBreaking Down Molecules

Heterotrophs break Heterotrophs break down glucose to gain down glucose to gain energy to carry out energy to carry out life activities.life activities.

They break down the They break down the glucose to make glucose to make ATP (Adenosine ATP (Adenosine Triphosphate)Triphosphate)

PHOTOSYNTHESISPHOTOSYNTHESIS

Diagram of ProcessDiagram of Process

Equation12 H2O + 6 CO2 + Light energy

C6H12O6 + 6 O2 + 6 H2O

Light is the Light is the main ingredientmain ingredient

White light is a combination of all colors White light is a combination of all colors of the visible light spectrum.of the visible light spectrum. Observe the visible light spectrum using a Observe the visible light spectrum using a

spectrophotometer. spectrophotometer.

Visible light ranges from wavelengths Visible light ranges from wavelengths measuring ~400 nm (violet) to ~700 nm measuring ~400 nm (violet) to ~700 nm (red) on the electromagnetic spectrum.(red) on the electromagnetic spectrum.

How do we see How do we see color?color? Pigments absorb Pigments absorb

certain wavelengths certain wavelengths of light and reflect of light and reflect all others.all others.

Look at the red Look at the red heart – What’s heart – What’s going on with the going on with the pigments?pigments?

Plant PigmentsPlant Pigments

Chlorophyll a Chlorophyll a

Chlorophyll bChlorophyll b

CaroteneCarotene

XanthophyllXanthophyll

Dark GreenDark Green

Yellow-greenYellow-green

OrangeOrange

YellowYellow

Light PhaseLight Phase Stage 1 – Energy is Stage 1 – Energy is

captured from sunlight.captured from sunlight. Photosystem 2 (PS2) – Photosystem 2 (PS2) –

Step 1Step 1 Photolysis – Light hits the Photolysis – Light hits the

thylakoid membrane of a thylakoid membrane of a plant and the electrons go plant and the electrons go through the electron through the electron transport chain to transport chain to produce a lot of energy produce a lot of energy (ATP) to split water (ATP) to split water moleculesmolecules

12 H12 H22O O 24 H 24 H++ + 6 O + 6 O22 + + EnergyEnergy

H+ trapped by NADPH+ trapped by NADP++ forming NADPH to carry the energy forming NADPH to carry the energy used during the dark phase (when glucose is made).used during the dark phase (when glucose is made).

Photosystem 1 (PS 1) – Step 2Photosystem 1 (PS 1) – Step 2 Phosphorylation – THE RECHARGEABLE BATTERY!Phosphorylation – THE RECHARGEABLE BATTERY! When ATP loses a phosphate, energy is released and ADP When ATP loses a phosphate, energy is released and ADP

is formed. is formed.

You gain phosphates by breaking down the food you eat.You gain phosphates by breaking down the food you eat. ATP is the energy needed to fuel the dark reaction. ATP is the energy needed to fuel the dark reaction.

Dark PhaseDark Phase Stage 2 – The chemical Stage 2 – The chemical energy stored in ATP energy stored in ATP and NADPH powers the and NADPH powers the formation of Glucose, formation of Glucose, using COusing CO22.. To fix carbon (change it To fix carbon (change it

into a useable form), you into a useable form), you use COuse CO22 and combine it, and combine it, split it and basically put it split it and basically put it through the wringer (the through the wringer (the Calvin Cycle) and then Calvin Cycle) and then combine it with ATP and combine it with ATP and NADPH to form CNADPH to form C66HH1212OO22 and give off Hand give off H22O.O.

The Process In GeneralThe Process In General

Light Hits Thylakoid

Light Phase

ExcitesElectrons

(move thru ETC)

H2O Splits(due to enzyme)

O2 ATP

NADPH

Dark Phase

CO2 GlucoseCalvin Cycle

ATP ADP

NADPH NADP+

RESPIRATIONRESPIRATION

Equation

C6H12O6 + 6 O2 + 6 H2O

12 H2O + 6 CO2 + Energy

Step One - GlycolysisStep One - Glycolysis CC66HH1212OO66 is broken is broken

down into two down into two 3-carbon molecules 3-carbon molecules called pyruvate called pyruvate (aka – pyruvic acid)(aka – pyruvic acid)

4 ATPs generated 4 ATPs generated but 2 ATPs required but 2 ATPs required so the net ATP so the net ATP production is???production is???

2

If OIf O22 is Present… is Present… Then it’s AEROBIC Then it’s AEROBIC

RESPIRATIONRESPIRATION1.1. Pyruvate enters Pyruvate enters

mitochondrionmitochondrion2.2. Pyruvate Pyruvate 2-carbon 2-carbon

molecule (acetyl) COmolecule (acetyl) CO22 is released here.is released here.

3.3. Acetyl attaches to Acetyl attaches to coenzyme A to form coenzyme A to form acetyl-CoAacetyl-CoA

Acetyl-CoA enters the Krebs Cycle…Acetyl-CoA enters the Krebs Cycle…

C C CO2

NADH

FADHThese are electron carrying molecules

which will dump electrons into ETC

CCCCCC

CCCCC

CO2CCCC

2ATPs

CCCC

Acetyl-CoAjoins 4-carbon

molecule

ELECTRON ELECTRON TRANSPORT TRANSPORT

CHAINCHAIN Occurs in the inner Occurs in the inner membranes of the membranes of the mitochondria.mitochondria.

NADH and FADH NADH and FADH donate electronsdonate electrons

Electrons pump Electrons pump hydrogen ions hydrogen ions across membrane across membrane

Phosphate added to Phosphate added to ADP to form ATPADP to form ATP

If OIf O22 is NOT is NOT Present…Present…

Then it’s ANAEROBIC RESPIRATION…Then it’s ANAEROBIC RESPIRATION… Another name for this is fermentation.Another name for this is fermentation. There are two types of fermentation There are two types of fermentation

LACTIC ACID LACTIC ACID ALCOHOLICALCOHOLIC

LACTIC ACID LACTIC ACID FERMENTATIONFERMENTATION

PyruvateGlucose Lactic

Acid

During vigorous exercise, lactate builds up In muscles when the tissue is deprived of oxygen. This allows glycolysis to still produce ATP as long as there is glucose but only 2 ATPs per molecule of glucose – MUCH LESS EFFICIENT THAN AEROBIC RESPIRATION.

ALCOHOLIC ALCOHOLIC FERMENTATIONFERMENTATION

PyruvateGlucose Ethyl

Alcohol

This happens in certain bacteria and fungus. For centuries this has occurred during the production of various alcoholic beverages such as beer and wine. This allows glycolysis to still produce ATP as long as there is glucose but only 2 ATPs per molecule of glucose – MUCH LESS EFFICIENT THAN AEROBIC RESPIRATION.

CO2

The Process In The Process In GeneralGeneral

GlycolysisGlucose (Net) 2 ATP

NoO

2O

2

Krebs Cycle

2 ATP

ETC34 ATP

Fermentation

LacticAcid

Ethanol