Cellular Respiration and Fermentation

How energy goes from chemical bond to a usable form…

Metabolism Overview

3. PHOTOSYNTHESIS 5. RESPIRATION

1. SUN

2. LIGHT ENERGY

4. CHEMICAL ENERGY

6. ATP

(CELL ENERGY)

Energy Production and Use in Cells

Energy for Life

ATP

ADP and P

Organic Compounds &

Oxygen

Carbon Dioxide & Water

1) Cellular respiration - The process of respiration is where organisms convert chemical energy into cellular energy, which is known as ATP.

2) Cellular respiration is similar to burning fuel (like gasoline combustion in your car).

How do we use “food”?

3) It occurs in both heterotrophs and in autotrophs - they both need ATP to use for cellular energy.

4) In the cells it begins in the cytoplasm and usually ends in mitochondria

Who and Where?

C6H12O6 + 6O2 6H2O + 6CO2 + ATP

In and Out - The chemical formula

C6H12O6 +Carbohydrates

6O2

Oxygen

6CO2 +

Carbon Dioxide

6H2O +ENERGY

Water

ATP

A 6-carbon molecule of glucose is separated into two 3-carbon pyruvate molecules and makes some ATP and NADH.

This process occurs in 4 steps that take place in the CYTOPLASM and does not require oxygen to be present.

Stage 1 - Glycololysis

a. 2ATP is used to started the reaction…

b. 4 ATPs are formed from the reactions

c. The yield is therefore 2 ATPs

d. The other 2 ATPs go back into the cycle to start it over again.

6. Stage 1 steps:

7) Aerobic Respiration has 2 stages:

a) Krebs Cycle

b) Electron Transport Chain

Aerobic Respiration in Mitochondria

The Kreb’s Cycle

aka the Citric Acid Cycle

a) ATP

b) FADH2

c) NADH

d) The FADH2 and the NADH then enter the electron transport chain

8. Products of the Kreb’s Cycle

The electron transport chain

a) ATPb) At the end of the ETC hydrogen

ions and the spent electrons combine with oxygen molecules forming H2O

c) In aerobic respiration oxygen is the final (terminal) electron acceptor.

9. The products of the electron transport chain (ETC)

If oxygen is NOT present the pyruvate produced during glycolysis continues on to anaerobic respiration.

Anaerobic respiration takes place in the cytoplasm.

Wait!!! What if there is no oxygen?

11) Anaerobic Respiration has 2 types:

a) Lactic Acid Fermentation

b) Alcoholic Fermentation

Anaerobic respiration (Fermentation)

a) Pyruvate is changed to lactate by removing two hydrogen.

b) This process is by bacteria and fungi to produce foods like yogurt and cheese.

c) Also used by muscle cells when oxygen is not present (called lactic acid build up.)

12. Lactic Acid Fermentation

a) Pyruvate is changed to ethyl alcohol by first removing CO2 and then 2 hydrogen.

b) This process is used by yeast to prepare many foods and beverages.

c) The release of CO2 causes dough to rise.

13. Alcoholic Fermentation

a) The total amount of energy that a cell can harvest depends on the presence or absence of oxygen.

b) Aerobic (with oxygen) gains 36 ATP.

c) Anaerobic (without oxygen) gains 2 ATP.

14. Aerobic vs Anaerobic

Living on Earth is expensive, but it does include a free trip around the sun every year.” --Unknown

Questions?