You get energy from the food you eat.

Directly or indirectly, all of theEnergy in living systems needed for

Metabolism comes from the sun.

Metabolism involves either using energyTo build molecules or breaking

Down molecules in which energyIs stored.

Photosynthesis is the process by which

Light energy is converted to Chemical energy.

Autotrophs are organisms that useEnergy from sunlight or

Inorganic substances to make Organic compounds.

Like plants use sunlight to Make glucose.

Heterotrphs are organisms that Must get energy from food instead

Of directly from sunlight.

We are heterotrophs because We can’t make our own food

In our cells.

Instead we use cellular respirationTo “burn” fuel in our bodies.

Almost all of the food we eat goesTo heat, but some of the energy

Goes into making ATP.

ATP (adenosine triphosphate) Provides cells with the energy

they Need to carry out life’s processes.

6CO2 + 6H2O + Light C6H12O6 + 6O2

In stage 1, light energy is absorbed.

Structures that will absorb lightContain pigments.

Chlorophyll is the primary pigment That absorbs mostly blue and red

Light and reflects green and yellow.

That reflection is why plants Are green.

Plants contain 2 types of chlorophyll,a and b chlorophyll.

Both types of chlorophyll play a Role in photosynthesis.

The pigments that produce yellowAnd orange colors in fall or

In fruits and vegetablesAre called carotenoids.

Pigments involved in plant Photosynthesis are located in the

Chloroplasts of leaf cells.

Clusters of pigments are embeddedIn the membranes of disk Shaped structures called

Thylakoids.

When chlorophyll absorbs light this causes 1

pair of chlorophyll electrons to “bounce around”

Instead of being “trapped” in a wire they are stored in chemical

bonds.

These “excited” electrons that leaveThe chlorophyll molecules are used

To produce new molecules that Temporarily store chemical energy,

Including ATP.

The series of molecules through whichExcited electrons are passed alongA thylakoid membrane are called

Electron transport chains.

NADP+ (in plants) -accepts electrons and is converted to NADPH

NADPH is an electron carrier thatProvides the high-energy electrons

Needed to make C-H bonds in stage 3.

In stage 3, energy is stored inOrganic molecules.

In the 1st and 2nd stages of Photosynthesis, light energy is used

To make ATP and NADPH, whichTemporarily store chemical energy.

In the 3rd stage of photosynthesis, Carbon atoms from the CO2 in

The air are used to make Organic compounds in whichChemical energy is stored.

This energy is stored in the formOf sugar…Glucose.

The transfer of carbon dioxide To organic compounds is called

Carbon fixation.

The most common method for Carbon fixation is the Calvin Cycle.

The Calvin cycle is a series of enzymeAssisted chemical reactions that

Produce 3 carbon sugars.

Photosynthesis is affected by Various types of environmental factors.

The most obvious is lightThen there is CO2 concentration

Also temperature

Cells transfer the energy in organic compounds (carbs, proteins, fats)

back to ATP

So for the most part, this is the Reverse of photosynthesis.

Metabolic processes that requireOxygen are called aerobic.

Metabolic processes that can goOn without oxygen are called

Anaerobic.

The primary fuel for cellular Respiration is glucose, but fats and

Proteins can also be used.

In the first step of cellular respirationGlucose is broken down in the

Cytoplasm during a process calledGlycolysis.

Glycolysis is enzyme assisted and Breaks down a 6 carbon glucoseTo 3 carbon sugars of pyruvate.

As glucose is broken down, some of Its hydrogens are transferred to

An electron acceptor, NAD+.

This forms the electron carrierNADH.

For respiration to continue, theElectrons eventually are donated

To other organic compounds,This recycles the NAD+.

In stage 2, more ATP is madeBy aerobic respiration.

When oxygen is present, pyruvateProduced during glycolysis enters a

Mitochondria and is converted toA 2 chain compound.

This reaction produces a carbonDioxide molecule, 1 NADH

Molecule and a 2 carbon acetyl group.

The acetyl group is attached to a Molecule called coenzyme A, forming

A compound called acetyl-CoA.

Acetyl-CoA enters a series of enzymeAssisted reactions called the

Kreps Cycle.

After the Krebs cycle, NADH and FADH2 now contain much of the

Energy that was previously storedIn glucose and pyruvate.

When the Krebs cycle is completed,The 4 carbon compound that began

The cycle is recycled, and Acetyl-CoA can enter the

Cycle again.

In aerobic respiration, electrons Donated by NADH and FADH2

Pass through an electron transportChain.

In eukaryotic cells, the electron Transport chain occurs in the

Inner membranes of the Mitochondria.

Fermentation follows glycolysisIn the absence of oxygen.

What happens when there is not Enough oxygen for aerobic

Respiration?

Then anaerobic respiration occurs.

Two important types of fermentationAre lactic acid fermentation And alcoholic fermentation.

During vigorous exercise, pyruvateIn muscles is converted to Lactate when there is not Enough oxygen present.

The lactic acid then created buildsUp and is what causes cramps.

In other organisms, like yeast,The three carbon pyruvate is

Broken down to ethanol, a 2 carbon compound, through a

Process called alcoholic fermentation.

Carbon dioxide is released During the process.

Ethanol is actually toxic to yeast.

Yeast will die with ethanol Concentrations of about 12%.

So naturally fermented wine and Beer can only be a maximum

Of 12% alcohol.