What is energy?

– ability to do work

Cars need energy to move

Animals need energy to grow, move, make noise, etc

Where do cars get energy?

– from burning fuel

–Specifically oil and gasoline

Chemical Energy is stored in fuels

- Burning oil and gasoline release energy in the form of heat and light ; The energy also allows the car to move.

- Gasoline is organic. When gasoline reacts with oxygen you get a combustion reaction. The products of ALL combustion reactions are carbon dioxide (CO2) and Water (H20)

What is our fuel?

- Food!

- Specifically Glucose (simple carb)

But where does the glucose in our food come from?

THE SUN!!!

Really? How?• Let go through step by step.

1. Where did your glucose come from?

2. How did the glucose get in the food?

3.How did she get the glucose?

4. How did the glucose get in the grass?

5. Where did the energy to make the glucose come from?

SO, long story short,

- the chloroplasts take energy from the sun and put it into a glucose molecule (Photosynthesis)

- through the food chain, glucose gets passed from organism to organism

- eventually mitochondria of some organism takes the energy back out, by breaking down the glucose (Cell respiration)

Types of Batteries

• Adenosine Triphosphate: ATP– cycles between ATP (high energy)

and ADP (low energy) by adding or removing a phosphate

ADP and ATP

ADP/ATP cycle

Types of Batteries• Electron Carriers: cycle between low

energy “empty” form and high energy “full” form by adding or removing electrons.

–We can “empty” these electron carriers to charge ATP

Types of Batteries

–There are three different electron carriers: NADPH; NADH and FADH2

Let’s start by getting the energy from the sun into the glucose molecule

Photosynthesis

Key terms:

• Heterotrophs: Organisms that get food from somewhere else–Examples??

• Autotrophs: organisms that make food for themselves–Photoautotrophs use light energy to

make their food• Examples?

–Chemoautotrophs use the energy in inorganic compounds to make their food• Examples?

• Understanding a little about light is important! Refer to your “Science of light and Color” assignment to help!

Photoautotrophs undergo Photosynthesis

• So what organelle is in their cells?

Granum (plural Grana)

Thylakoid

Stroma

What makes it Green?

• Pigment called Chlorophyll (There are two chlorophylls)

• A pigment is a substance that absorbs light

What color light bounces off chlorophyll?

GREEN!!!

• Carotenes and xanthophylls*: other plant pigments (orange and yellow) that absorb different wavelengths of sunlight than the chlorophylls do.

• When can we see these??

* ZAN-tho-fills

FALL!!!

Overall Reaction• Photosynthesis requires MANY reactions but we can

summarize it with the following reaction

• Like all reactions, photosynthesis needs:

6CO2 + 6H2O + 6O2

(Glucose)

C6H12O6

• Two Phases of PhotosynthesisLight reactions: need light;

- uses light energy to “charge” two energy molecules: ATP and NADPH

- proteins needed for the reaction are embedded in the thylakoid membrane

- Uses: 6H2O produces: 6O2

• Two Phases of PhotosynthesisCalvin cycle: doesn’t need light;

- Uses the ATP and NADPH “charged” by the light reactions to link CO2 together to build C6H12O6

- Enzymes for the calvin cycle are found in the stroma

Reactant: 6CO2 Product: C6H12O6

Putting it Together

Glucose will do one of two things:

1. Move to the mitochondria to be converted into ATP through Cell respiration

2. Go through dehydration synthesis to build a big starch chain and be stored for future use

Follow the Energy

• Where did the energy start?

• Where did it go next?

• Where is it at the end of photosynthesis?

Factors that affect Photosynthesis

• Light intensity (how bright/strong)

• Wavelength (color of light)

• Temperature: 0 – 35 degrees C

• Water

• CO2 levels

Why do each of these affect photosynthesis?

Exceptions to the Rules:

• Autotrophic Protists:

–Example: Algae, volvox and Euglena

Exceptions to the Rules:

• Autotrophic Bacteria:

–Example: Cyanobacteria (“Blue” bacteria)

Exceptions to the Rules:• Heterotrophic plants: some plants

get food from other organisms

–Mistletoe: makes food AND takes sap (high in sugar) from other trees

Exceptions to the Rules:

Venus Flytrap: traps and digests insects as a food source

Exceptions to the Rules:

Dodder plant: roots grow into other plants and steals water and glucose

How do we get the energy back out?

Cell Respiration – a series of chemical reactions that extract energy from glucose to “charge” ADP to make ATP.

Starts in the cytoplasm and ends in the mitochondria.

How do we get the energy back out?

Overall reaction

+ 6O2 6CO2 + 6H2OC6H12O6

ATP

Two types of Cellular Respiration

Anaerobic: no free oxygen required

- performed by most bacteria

- Also by yeast and animal cells when lacking O2

- two steps: Glycolysis, fermentation

- makes 2 ATP per glucose

Two types of Cellular Respiration• Aerobic: requires FREE oxygen, O2 gas to get

ATP from glucose

– three steps: glycolysis, krebs, electron transport chain

– performed by plants, animals, yeast, protists, fungus.

– Generates 36 ATP per glucose

Anaerobic step 1: Glycolysis• Occurs in cytoplasm

• Summary: split glucose in half to charge a few ATP and NADH

• Reaction: Glucose 2 pyruvate

• Energy molecules used: 2ATP

• Energy molecules made: 4ATP and 2NADH

Fermentation• Occurs in cytoplasm• Summary: “empty” the NADH so we can

repeat glycolysis with the next glucose

–2Pyruvate CO2 and Ethanol (yeast)

or

- 2Pyruvate Lactic Acid (bacteria and muscle cells)• NO MORE ATP CHARGED!

ATP Tallies:

Anaerobic:

- Glycolysis: used 2, made 4

- Fermentation: used 0, made 0

Total: +2 per glucose

Aerobic step 1: Glycolysis

• SAME AS STEP 1 OF ANAEROBIC!

Krebs• Occurs in mitochondria

• Summary: break down pyruvate into CO2; use energy in pyruvate to charge ATP, NADH and FADH2

KrebsReaction:

–2Pyruvate 2Acetyl-CoA + CO2

–2Acetyl-CoA 4CO2

–Energy molecules made: 2ATP + 2FADH + 6NADH

–Can bacteria do Krebs??

Electron Transport Chain• Occurs in mitochondria

• Summary: Gather up ALL the electron carriers and “empty” them to “charge” lots of ATP

Electron Transport Chain• Reaction:

–O2 H2O

Energy molecules USED: 10 NADH (from krebs and glycolysis) + 2 FADH (from krebs)

Energy molecules MADE: 32 ATP

ATP Tallies:

Aerobic: - Glycolysis: used 2, made 4 - Krebs: used 0, made 2 - ETC: used 0, made 32Total: +36 ATP per glucose

Overall Energy Summary for Aerobic Respiration

Glucose + 2ATP 2 Pyruvate + 4ATP + 2NADH

Reactants (used up/broken down) Products (created/built up)

2 Pyruvate 2CO2 + 2Acetyl-CoA + 2NADH

2Acetyl-CoA 6NADH + 2FADH2 + 2ATP+ 4CO2

10NADH + 2FADH2 + 6O2 32ATP + 4CO2 + 6H2O

What’s Left?

Final Reaction for Aerobic Respiration

Putting it together:

Chloroplast

Sun

Mitochondria

C6H12O6 + O2CO2 + H2O

36ATP