PhotosynthesisThe process autotrophs use to

make glucose sugars from carbon sources, water, and light energy

6CO2 + 6H2O C6H12O6 + 6O2

sunlight

Radiant energycarbohydrates

Respiration

How energy flows through the ecosystem

Photosynthesis

HeterotrophsHeterotrophs

Autotrophs

heat

How organisms get carbon energy

1. Autotrophs: able to produce own glucose – Ex: plants, algae, cyanobacteria– Also called: producers

2. Heterotrophs: must take in glucose from outside source

– Ex: animals, fungus, most bacteria, protozoans

– Also called: consumers

RespirationPhotosynthesis

Stored Chemical Energy(in the form of Glucose)

Light Energyfrom the sun

Energy for Cellin the form of ATP

Using oxygen; releasing w

ater & CO

2

Usi

ng w

ater

& C

O 2; re

leas

ing

oxyg

en

Why is a carbon source from sugars so important?• The carbons are needed to make ATP

molecules, which provide energy for metabolic reactions.

Adenine Ribose 3 Phosphate groups

ADP and ATP

• To get energy out of ATP, the bond between two phosphate groups is broken.

ADP ATP

Energy

EnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)

Partiallychargedbattery

Fullychargedbattery

Where and how are sugars made?Light Energy

Chloroplast

CO2 + H2O Sugars + O2

Photosynthesis video

Click on image to play video.

Pigments

• Chlorophyll is a pigment, a molecule that can absorb light energy.

• Unused light is reflected.

• What is the color of the wavelength least used by chlorophyll?

Absorption of Light byChlorophyll a and Chlorophyll b

V B G YO R

Chlorophyll b

Chlorophyll a

2. Photosynthesis pigments

• A. chlorophyll a(light green)

• B. chlorophyll b(dark green)

• C. xanthophyll(yellow)

• D. carotenoid– (orange)

Chromatography

• The process of separating colored solutions to determine the number of pigments in the solution

How does photosynthesis work?

1. Light dependent reaction

2. Calvin cycle

ChloroplastLight

Sugars

CO2

Light-Dependent Reactions

CalvinCycle

NADPH

ATP

ADP + PNADP+

Chloroplast

H20

O2

Step 1: Light dependent reaction

HydrogenIon Movement

Photosystem II

InnerThylakoidSpace

ThylakoidMembrane

Stroma

ATP synthase

Electron Transport Chain Photosystem I ATP Formation

Chloroplast

Light dependent reaction

• Pigments (chlorophyll) inside of the chloroplasts are arranged into photosystems (PSI and PSII).

• Photosystems absorb sunlight.

• Electrons become energized and help to produce NADPH.

3. Light Dependent

reactions• location:

grana of chloroplast• Photosystem II: energized chlorophyll releases

energy to split water into Oxygen (released) and Hydrogen (the H is carried by NADP to be used later in Calvin cycle)

• Photosystem I: energized chlorophyll releases energy to add phosphate to ADP to make ATP (to be used later in the Calvin cycle)

Light dependent video (1)

Click on image to play video.

Light dependent video (2)

Click on image to play video.

Step 2: Calvin cycle

ChloropIast

CO2 Enters the Cycle

Energy Input

5-CarbonMoleculesRegenerated

Sugars and other compounds

6-Carbon SugarProduced

4. Light independent reactions(Calvin cycle)

• Location: stroma (fluid) of chloroplast

• Carbons? CO2 is “fixed” by RuBP & begins the cycle becoming PGA, then PGAL after hydrogen (from NADP) and energy (from ATP) are added

• Products? RuBP is recycled for next time & Glucose (sugar/food) is made (from 6 turns of cycle)

Calvin cycle

• The NADPH supplies the energy needed to change the CO2 taken into the cell into a 6 carbon molecule.

• This 6 carbon molecule is made into sugars.

glucose

Sunlight

Light-dependentReactions

water

oxygen

Calvin Cycle

Carbon Dioxide Glucose

NADPH2

ATP

Within chloroplasts

RuBP

PGA

PGAL

Calvin cycle video

Click on image to play video.