Cellular Respiration

What is Cellular Respiration?• When organisms capture the _______

stored in the chemical bonds of food molecules such as glucose and other sugars made in photosynthesis.

• Cellular respiration builds a molecule called• ATP, which powers all work within cells.

energy

Sucrose: A disaccharide

Glucose Fructose

Monosaccharides

ATP

Why ATP?• Why do we transfer the energy in the

chemical bonds of glucose into ATP?– ATP is small– ATP is stable – but not too stable– The bond between the 2nd and 3rd phosphates

in ATP holds a lot of energy.

Aerobic Respiration

1. Requires Oxygen

2. Many ATP molecules are made by the mitochondria from the glucose.

Label the parts of the mitochondrion

Intermembrane space

3 Steps to Cellular RespirationBreaking the bonds of Glucose for ATP

1. Glycolysis: • Occurs in the cytoplasm • No O2 required

• 2 made

2. Krebs or Citric Acid Cycle:• Occurs in the matrix• CO2 gas is released here

• 2 made

3. Electron Transport Chain• Occurs in the folds of the inner membrane (crista)• Uses O2 and about 32 and water is made.

ATP

ATP

ATP

“Glyco” “lysis” literally means “sugar” “splitting”

Breaking the First Bond of Glucose: Glycolysis

P

P

Anytime bonds break, energy is released. Energy carriers can capture some of that

energy. The remainder is released as heat.

NAD+

NAD+NADH

NADH

NADH = +2

P

P

When bonds break, ATP can be made from that energy

ADP

ADP

ATP

ATP

ATP = +2

These smaller sugar molecules made from glycolysis are called Pyruvate

Just observe what happens next….

The Krebs Cycle takes place in the Matrix of the Mitochondrion, where more bonds are broken.

NAD+

NAD+NADH

NADH Food for thought… what gas am I?The CO2

that gets exhaled

Citric Acid

The Krebs Cycle takes place in the Matrix of the Mitochondrion, where more bonds are broken.

NAD+NADH

The Krebs Cycle takes place in the Matrix of the Mitochondrion, where more bonds are broken.

NAD+NADH

The Krebs Cycle takes place in the Matrix of the Mitochondrion, where more bonds are broken.

P

ADPATP

NADHNAD+

The Krebs Cycle takes place in the Matrix of the Mitochondrion, where more bonds are broken.

FADHFADH2

The Krebs Cycle takes place in the Matrix of the Mitochondrion, where more bonds are broken.

What is gained per glucose molecule during the Krebs Cycle?

NADH = +4

FADH2 = +1

• But there were two molecules of pyruvate that entered the Krebs Cycle…

• How many would actually be produced in this case?

+8

+2

Energy Carriers

ATP = +1+2

What kind of waste was made in the Krebs cycle?

6 CO2 gas!

Where is the Electron Transport Chain?

Inside the mitochondrion.

Folds of the inner membrane known as cristae.

Many ATP molecules willbe produced in these

Electron Transport Chains

What are the energy carriers NADH and FADH2 for?

• They power the Electron Transport Chain that make a lot of ATP!

FADH2

NADH

FADH2

FADH2

ATP

ATP

ATPATP

ATP

During this process, oxygen gas is used, LOTS of ATP is made, and water is created.

6 O2

NADHNADH and

FADH2

2 ATP 2 ATP 34 ATP

Electron Transport Chain

Cellular Respiration Equation:

C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP (Glucose)Light Reactions

• With a neighbor, fill in the steps in this cycle of Photosynthesis and Respiration.

• We will check your answers when you are done!

Photosynthesis and Respiration

Fermentation: Anaerobic

Respiration 1. Occurs when there is not

enough oxygen to sustain an activity, so ATP cannot be made in the mitochondria.

2. Two basic types:

a. Lactic Acid Fermentation (in animals)

b. Alcohol Fermentation (in micro-organisms such as yeast)

3. Fermentation keeps glycolysis going, so at least 2 ATPs can still be made, until oxygen levels are restored.

Glycolysis