EnergyThe ability to do work

Energy LawsLaws of Thermodynamics (energy flow)

1. Law of the Conservation of Energy - Energy can not be created nor destroyed– Energy is converted (changed) from one form to

another – When we eat food

2. Law of Entropy - Energy can not be converted with out the loss of useable energy – The loss of energy is called Entropy– Light bulb – light energy, but looses heat

The Flow

Plants

Animals

How do organisms get their energy?

Autotroph – makes its own food (doesn’t eat)

Heterotroph – needs to eat to obtain energy

Autotroph Energy

Photosynthesis

• The process of turning light energy from the sun into chemical energy used by the cell.

Heterotroph Energy

Cellular Respiration

• The process of breaking down organic molecules to release energy used by the cell

PhotosynthesisThe process of turning light energy from the sun into chemical energy used by the cell.

Need:• Carbon dioxide – CO2

• Water – H2O• Sunlight

To Produce:• Glucose – C6H12O6

• Oxygen- O2

Put it all together……

6CO2 + 6H2O C6H12O6 + 6O2

Sunlight

Where?

• Photosynthesis takes place in the chloroplasts

• Chlorophyll absorbs the light and starts the photosynthesis reaction– Chlorophyll is a pigment found in the chloroplasts– It is what makes plants green

Parts of a Chloroplast

Outer MembraneGranum – Stacks of Thylakoids - where the chlorophyll is

Stroma

Lamellae

Cellular RespirationThe process of breaking down organic molecules to release energy used by the cell

Need• Glucose - C6H12O6

• Oxygen - O2

To Produce• Carbon Dioxide - CO2

• Water - H2O• Energy

Put it all together…..

C6H12O6 + 6O2 6CO2 + 6H2O + Energy

The Energy Currency of The Cell

ATP The unit of energy used in the cell

• Produced during cellular respiration• When the ATP molecule is broken it releases

energy• ATP breakdown takes place in the

mitochondria

Aerobic and Anaerobic Respiration

Aerobic – requires oxygen

Anaerobic – does not require oxygen

Aerobic Respiration

• Uses oxygen to make ATP• What happens during cellular respiration• Produces more ATP than anaerobic respiration• Preferred way to make energy

Anaerobic Respiration

• Some organisms do not use oxygen to make energy – yeast and some bacteria

• Will happen when there is not enough oxygen• This type of respiration does not produce as

much ATP as aerobic respiration

Two Kinds of Anaerobic Respiration

1. Lactic Acid Fermentation – produces lactic acid in the cells (muscle aches, sour cream)

2. Alcohol Fermentation – produces alcohol and carbon dioxide in the cells (bacteria and yeast)