Energy in food is stored as carbohydrates, proteins & fats. Before you can use that energy, it must be released and transferred to ATP.

Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen.

Formula: C6H12O6 + 6O2 6CO2 + 6H2O + 34

ATP Glucose+ Oxygen CO2 + H2O +

Energy

If cellular respiration took place in just one step, all energy would be released at once and our cells need to control this.

GlucoseC6

Pyruvate Pyruvate

C3 C3

2 ADP + 2NAP+ 2 ATP + 2NADH

Takes place in the cytoplasm Net gain of 2 ATP Takes place without oxygen (anaerobic) NADH is formed (electron carrier)

Interesting Fact:Since bacteria don’t have any membrane-bound organelles such as mitochondrion, they can only produce ATP by glycolysis!

1. Anaerobic Respiration - If no oxygen is present, pyruvate goes through a process called “fermentation.”

2. Aerobic Respiration – If oxygen is present, pyruvate enters the mitochondria and enters the “Kreb’s Cycle.”

Glycolysis

C3

C6

Two Pathways

Anaerobic

Or:

Aerobic

What’s the difference?

2. Krebs Cycle – A stage of aerobic (requires oxygen) respiration in which pyruvate is converted into CO2, water and ATP.

~ Takes place in the mitochondria

The Kreb’s Cycle is a continuous cycle of electrons transferred to energy carriers.

Citric acid is broken down, CO2 is released (you exhale it out), and ATP is released to be used in cellular activities.

What happens to all of the high energy electrons???

Citric Acid

A protein in the membrane called ATP synthase. These enzymes convert ADP to ATP.

34 ATP are produced (Lots of energy!)

In the absence of oxygen, glycolysis produces just 2 ATP molecules per glucose.

In the presence of oxygen, everything changes.

The Kreb’s Cycle & electron transport chain allow the cell to produce 34 more ATP molecules.

36 total ATP!

18 times as much can be generated from glucose in the presence of oxygen.

The final waste products are water and carbon dioxide.

38% of the energy in glucose is used to make ATP. 62% is released as heat. (This is why you become warm when you exercise).

Photosynthesis Cellular Respiration

Function

Location

Reactants

Products

Equation

Photosynthesis & Cellular Respiration are almost opposite processes.

Photosynthesis “stores” energy Cellular Respiration “releases” energy What do you notice about the

equations????

Glycolysis

C3

C6

Two Pathways

Anaerobic

Or:

Aerobic

What’s the difference?

~ Takes place in the cytoplasm

Pyruvate

Alcohol Lactic Acid(plants) (animals)

2 ATPCO2

Lactic acid is produced in your muscles during rapid exercise when the body cannot supply enough oxygen to the tissues.

The buildup of lactic acid causes a painfull burning sensation.