Autotrophs= producers: organisms that use photosynthesis to make food

Heterotrophs= consumers: organisms that must eat other organisms to get their energy

Photosynthesis & cellular Respiration form a cycle in the environment. The products for one are the reactants for the other.

Sunlight energy

Photosynthesis

Oxygen & food

Cellular respiration

Carbon dioxide

Light comes from the sun in tiny packets called photons. Sun’s energy contains a whole range of types of light. Plants are most concerned with the visible spectrum of the light– the colors, ROYGBIV.

Objects appear certain colors because they reflect that wavelength of light. Example: plants appear green because chlorophyll absorbs all other colors of light and reflects green. Some plants have carotenoids, which reflect orange, red, yellow, and brown.

chlorophyllscarotenoids

• Chloroplasts are the organelles responsible for photosynthesis.

• Chlorophyll makes it appear green.

• Thylakoids– flattened disks inside the chloroplast

• Granum– a stack of thylakoids

• Stroma– fluid around the thylakoids

Thylakoids are made of membranes– what are the molecules that make up membranes?

Photosynthesis really occurs on the thylakoid membrane.

Steps of photosynthesis

• Light-dependent reactions (require light to begin, occur on the thylakoid membrane)

1. Light hits the chlorophyll molecule

2. electrons become excited or activated

3. electrons move down a series of proteins called the electron transport chain

4. water is split into H+ & oxygen

5. ATP & NADPH are made

Steps of photosynthesis (cont.)

• Light-independent reactions (do not require light to begin, occur in the stroma)6. NADPH and ATP travel from the light reactions and provide energy to make the Calvin Cycle7. Carbon dioxide reacts with other molecules8. a long chain reaction eventually produces glucose and other food molecules

6CO2 + 6H2O C6H12O6 + 6O2

The reaction of photosynthesis also starts with light and requires chlorophyll.

The reactants are carbon dioxide & water. The products are glucose & oxygen.

Helper molecules– are made during one part of the pathway and are used during another, later, part of the pathway

NADPH ATP

NADPH and ATP are made during the light reactions and are necessary for the dark reactions.

2 3

4

5 6

7

thylakoids

1

8

Remember that photosynthesis & cellular respiration are a continuous cycle– the reactants of one are the products for the other

C6H12O6 + 6O2 6CO2 + 6H2O

6CO2 + 6H2O C6H12O6 + 6O2

photosynthesis

Cellular respiration

ATP– adenosine triphosphate= energy

Cellular Respiration takes place in three phases:

• GlycolysisThe splitting of (6-carbon) glucose into 2 (3-carbon) pyruvates

• Krebs Cyclechain reaction producing ATP, NADH, &

FADH2, releasing of CO2

• Electron Transport Chainmassive production of ATP

Glycolysis

• Occurs in the cytoplasm right outside the mitochondria

• Splits (6-carbon) glucose into 2 (3-carbon) molecules called pyruvate

• Produces 2 ATPs

Cleavage– splitting in half

Krebs Cycle

1. Pyruvate is converted into Acetyl co-A

2. Carbon dioxide is produced

3. Acetyl co-A enters the cycle

4. A little ATP is produced

5. NADH & FADH2 (helper molecules) are produced.

Electron Transport chain

• Occurs on the inner membrane

• Energy from NADH & FADH2 provide electrons

• Over 30 molecules of ATP are made

• Oxygen is the final electron acceptor

Mitochondrial matrix

Electron Transport

Chain

Fermentation (anaerobic)

If oxygen is absent, the Krebs cycle and electron transport chain will not take place.

Fermentation happens after glycolysis if oxygen is absent.

1. lactic acid fermentation

2. alcoholic fermentation (produces ethyl alcohol)