Energy Transfer In Plants

Changing the Sun’s Energy Into Useable, Stored Energy

All Life Needs Energy!!

Some life uses a process called chemosynthesis to make life possible.

Bacteria can get energy from thermal vents on the ocean floor!!!

Hydrogen sulfide chemosynthesis - CO2+O2+4{H2S}→CH2O+4{S}+3{H2O}

But even this depends on photosynthesis!! (O2 from plants)

Chloroplast

Plant Cell

Sunlight

Parts of the Plant Cell

Life Needs Useable Energy

Remember!! ATP is the useable form of energy in a cell!

In order for a plant to make ATP they must perform 2 processes, Photosynthesis & Cellular Respiration

Plants Do BOTHBOTH!!

Photosynthesis with Chloroplasts

And Cellular Respiration with Mitochondria

Where Does It Start?Photosynthesis

begins with Sunlight, when it hits the leaves of plants (and some protists or bacteria)

Photosynthesis has 3 stages

I. Capture Light Energy

II. Make Chemical Energy

III. Store Energy In Carbohydrates

Photosynthesis: Stage 1

Light hits the chloroplast and is absorbed by a pigment called chlorophyll

A pigment is any light absorbing substance

Stage 1: ContinuedIn Stage 1, the

energy from the light splits H2O into three parts: Oxygen (O2) Hydrogen Ions (H+) Electrons (e-)

Sunlight

2 H2O

O2

e-

4 H+

Chlorophyll

electron{membrane of chloroplast

Photosynthesis: Stage 2

The H+ and e- are pushed through the electron transport chain to make NADPH

NADPH is like a rechargeable battery

membrane of chloroplast

e-

NADPH

Electron Transport Chain ATP

Photosynthesis: Stage 3This stage DOES NOT require LIGHT. NADPH provides the energy to combine CO2

molecules into carbohydrates such as glucose (C6H12O6)

This process is called the “Calvin Cycle”

Calvin Cycle

CO2

ADP

ATPNADP+

NADPH

3 Carbon Sugars

Carbohydrates

Photosynthesis: The Reaction

(6) CO2 + (6) H2O C6H12O6 + (6) O2Light

Enzymes

Reactants: Carbon Dioxide & Water

Products: Glucose & Oxygen

What’s Next?

Some glucose is stored as starch.

The rest of it goes to the cytoplasm to begin to make ATP through Cellular Respiration!!