Chemical Energy, ATP, & Photosynthesis Chapter 4 Sections 4.1, 4.2, and 4.3.

Chemical Energy, ATP, & Photosynthesis

Chapter 4 Sections 4.1, 4.2, and 4.3

4.1 How do living things get ATP?

ATP is the energy carrier in living things – it is usable energy for the cell (chemical potential energy).

ATP stands for Adenosine triphosphate.Living things get ATP from breaking down

carbon based molecules. (carbohydrates & lipids)

Starch molecule

Glucose molecule

This is how it works

phosphate removed

Let’s see how it works

https://www.youtube.com/watch?v=SCOPNyXy_aU

4.2 & 4.3 Photosynthesis

The process of photosynthesis captures energy from sunlight and converts it into sugar (glucose - CPE).

This process happens in organisms called autotrophs or producers. (Need to make their own food)

This process takes place in and organelle called the chloroplast.

The chloroplast has a green pigment in it called chlorophyll that is responsible for capturing the light energy.

Let’s label the inside of a chloroplast

C6H12O6 (glucose)

Contains: chlorophyll

4. thylakoidsunlight

1 six-carbon sugar

3. 6H2O

7. 6CO2 from the atmosphere

5. 6O2

chloroplast2

9

6. Energy carrying molecules are being transferred to light independent reactions

stroma (fluid outside the thylakoids)

8. Light independent reaction

1.

So how does photosynthesis work?

The first stage of photosynthesis is called the Light Dependent Stage.

Purpose: To capture and transfer energy.First, light is captured by the chlorophyll in

the thylakoid.Thylakoids: membrane enclosed

compartments; membrane contains chlorophyll & other light-absorbing molecules. Grana: stacks of thylakoids

The Light Dependent Stage

Second, the energy is transferred along the thylakoid membrane and water is broken down. Oxygen molecules get released at this point.

Third, energy is then transferred to ATP to be used for the second stage of photosynthesis.

So how does photosynthesis work?

The second stage of photosynthesis is called the Light Independent Stage/ Calvin Cycle/ Dark Cycle.This process takes place in the stroma.

Stroma: The fluid outside of the thylakoids.First, carbon dioxide is added from the

atmosphere to help in the chemical reactions.Second, a molecule of a simple sugar (glucose)

is formed. This molecule stores some of the energy captured from the sun.

The chemical formula for photosynthesis

6CO2 + 6H2O + light C6H12O6 + 6O2

(reactants)

(products)

Carbon dioxide plus water plus light

yields Glucose and oxygen

What kind of energy transformation takes place in photosynthesis?

Radiant (light) Chemical (with a loss of heat of course!)

http://www.youtube.com/watch?v=eo5XndJaz-Y

Chemosynthesis

Some organisms still make their own food, but they do not use light - they use chemicals.

Chemosynthesis is the process of using chemical energy to make carbon based molecules.

This is because they are found in areas (ex: deep in the ocean) that never receive light.