Warm-UP

List the products of the photosynthesis reaction.

Do we use these products for our own life processes?

If so, where do we get them?

Cellular RespirationGeorgia Performance Standards-

- Relate the complexity and organization of organisms to their ability for obtaining

& transforming the matter and energy used to sustain the organisms.

What is Cellular Respiration?• The process that releases energy by

breaking down food molecules in the presence of oxygen.

• Cellular Respiration is carried out by autotrophs and heterotrophs.

How do cells make use of the energy How do cells make use of the energy gained?gained?

Glucose- Glucose- One gram of glucose contains a lot of One gram of glucose contains a lot of energyenergy One gram of glucose (when burned in One gram of glucose (when burned in the presence of oxygen) releases 3811the presence of oxygen) releases 3811 calories calories of of energy.energy.

calorie- amount of energy needed to raise the calorie- amount of energy needed to raise the temperature of water 1 degree Celsius.temperature of water 1 degree Celsius.

This type of calorie is not the same as Calories in This type of calorie is not the same as Calories in food, these are kilocalories.food, these are kilocalories.

Cells can Cells can NOTNOT “burn” glucose, “burn” glucose, they must gradually they must gradually release the energyrelease the energy from glucose and other food from glucose and other food compounds.compounds.

Pathways of Cellular Respiration• Complete Cellular Respiration occurs in the presence of oxygen

and contains

glycolysis Krebs cycle electron transport chain

Each of the 3 stages captures some of the chemical energy available in food molecules.

If the energy was released all at once, it would be explosive!!!

Pathways of Cell Respiration AEROBIC- “w/

oxygen”

1. Glycolysis2. Krebs Cycle3. Electron transport chain (ETC)

NET GAIN ATP= 36 ATP

ANAEROBIC- “no oxygen”

1. Glycolysis2. Fermentation

(ex. Alcoholic and lactic acid)

NET GAIN ATP= 2 ATP

Stage ONE: GLYCOLYSIS

• Glycolysis- the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3 carbon compound.

• Energy releasing process, but needs to “invest” energy to utilize more in the long run.

• INVESTS 2 ATPs 4 ATPs • NET GAIN OF E = 2 ATPs• Glycolysis also removes 4 high energy electrons, passes

them to an ______ _______ called NAD+. • NAD+ NADH . NADH carries high energy electrons from

glucose other pathways in the cell.

What if Oxygen Isn’t Present??• If oxygen is not present, glycolysis is

followed by a different path called FERMENTATION.

- releases E without oxygen aka “anaerobic”

- cells convert NADH NAD+; passing high E electrons back to pyruvic acid.

Why? Allows glycolysis to make more ATPs.

2 Types of FermentationPurpose: To regenerate NAD+ so glycolysis can continue!

• Alcoholic Fermentation

pyruvic acid + NADH alcohol + CO2 + NAD+

Ex.

• Lactic Acid Fermentationpyruvic acid + NADH lactic acid + NAD+

Ex. Burning sensation caused by exercise due to loss of oxygen. Lactic acid ferm. Replaces energy w/ ATPs

If Oxygen Is Present: The Krebs Cycle

• Oxygen is required to release 90% of energy stored in glycolosis.

• We breath or respire to release oxygen into our cells, and obtain energy.

• The process is aerobic.• After glycolysis, When oxygen is

present , pyruvic acid is released, then cellular resp. continues to the Kreb’s cycle.

• During the Kreb’s cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

• This is why we release CO2 as we exhale.• The Krebs cycle occurs in the mitochondria…the cells

energy power house.• NADH and FADH2 produces from Krebs pass high E

electrons to the electron transport chain.

Electron Transport Chain

• As the Krebs Cycle produces energy, the electron carriers are passed to the electron transport chain to convert ADP to ATP (energy!)

• ETC is last phase of aerobic Cellular respiration• What is created from the ETC?

– ATP -H20 -O2

TOTALS FOR CELL RESPIRATION- 36 ATP

18X more efficient at producing/ releasing energy from glucose than glycolysis and fermentation.

What types of Energy are used during exercise?

• Stored ATP

• lactic acid fermentation

• Cellular respiration

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