Krebs Cycle

Occurs here

ETC occurs here

Cellular Respiration:• A series of BIOCHEMICAL PATHWAYS… the

product of 1 reaction is the reactant of the next reaction

• Occurs in the mitochondria ( & cytoplasm)• Is the process of creating ENERGY…ATP!!!!• food broken down into organic molecules,

ultimately broken down into GLUCOSE– glucose changed into/converted into ATP (ENERGY)

• enzyme controlled

CR• Occurs in BOTH PLANTS AND ANIMALS• Has 3 stages:

1. Glycolysis – anaerobic: w/o Oxygen2. Krebs Cycle (aka: Citric acid cycle) – aerobic: require oxygen3. Electron Transport Chain (ETC) - aerobic

Glycolysis:

• Occurs in the cytoplasm (cytosol)• Chemical RXN where sugar-

GLUCOSE is broken down into 2 Pyruvic Acid molecules • Produces 2 ATP molecules for every

1 glucose molecule• NAD provides energy for the change

(an e- energy carrier)

Products from Glycolysis move into the Mitochondria

THE PRODUCT (Pyruvic Acid) WILL THEN BE USED AS THE REACTANT IN THE NEXT REACTION

Hence…Biochemical Pathway

CK ?? Topic CR Date: 10-11-101. What is the purpose of

Cellular Respiration?2. Where are the 2 places does

CR occurs?3. What are the 3 stages of CR?

CK ?? Topic CR Date: 10-11-10

4. How many usable ATP result from Glycolysis?

5. What is the second stage of CR?6. Where does the second stage take

place?7. What does the term aerobic

mean?

Stage 2Krebs (Citric Acid Cycle):

• Oxygen is required – Aerobic Respiration• A series of chemical rxns… a cycle

– Pyruvic Acid is further broken down:• into Acetyl CoA• CO2 is produced and • released into the air from animal cells• Or in plants move to the chloroplasts to be

used for photosynthesis

Pyruvic Acid is further broken down:

• 2 ATP are produced and• NADH & FADH are produced (high

energy electron carriers) which will provide the energy to bond the last phosphate in ADP to create ATP!

ENERGY

Citric Acid Cycle:

• Takes place in the matrix of the mitochondria

In summary:

Pyruvic Acid is further broken down into Acetyl CoA as it enters the Krebs Cycle

Stage 3-Electron Transport Chain:

Stage 3-Electron Transport Chain:

• Occurs in the inner Mitochondrial Membrane

• Majority of the ATP (34 ATP) are produced during ETC

• The high-energy electrons produced during the Krebs Cycle (NADH and FADH2) are used to convert ADP into ATP

Chemical Formula Cellular Respiration:

Sugar + Oxygen Energy + Carbon Dioxide + Water

C6H12O6 + 6O2 36 ATP + 6CO2 + 6H2O

Glycolysis:• Goal: To break down sugar into 2 Pyruvic

Acids• Who: Both plant and animals• Where: In the cytoplasm of the cell• Products: 2ATP, 2NADH, 2 Pyruvic

Krebs cycle:• Goal: convert (change) the pyruvic acid

into NADH and FADH2

• Where: mitochondria• Products: Energy carriers: NADH &

FADH2, CO2 (released to environment) and 2 ATP

Electron Transport Chain(chemiosmosis making ATP!!)

• Goal: break down NADH and FADH2 to produce ATP

• Where: Mitochondria membrane• Products: 32 -34 ATP

AS A RESULT OF AEROBIC CELLULAR RESPIRATION:

• 2 ATP FROM GLYCOLYSIS• 2 ATP FROM KREBS CYCLE• 32-34 ATP FROM THE ETC• TOTAL OF:

– 36-38 ATP FOR EVERY MOLECULE OF GLUCOSE

IF NO OXYGEN IS AVAILABLE…

• Anaerobic Respiration (FERMENTATION):– Begins with Glycolysis – DOES NOT REQUIRE OXYGEN

• Also known as FERMENTATION

2 types of FERMENTATION

1. Alcoholic fermentation2. Lactic acid fermentation

Lactic Acid Fermentation:

• Pyruvic acid converted (changed) into lactic acid

• Used to make cheese, yogurt, and is the stuff that accumulates in muscles (sore)

• 2 ATP only

Alcoholic Fermentation:

• Used to make beer, wine• Yeast used in process• 2 ATP only

Reproduce

Through

BUDDING!!

Clearly Not as efficient as

aerobic respiration

•Photosynthesis and cellular respiration are opposite rxns.

Photosynthesis & CRare opposite rxns.

Photosynthesis :• removes Carbon Dioxide from the

atmosphere and puts back oxygen.

Cellular Respiration:• Removes oxygen from the atmosphere

and puts back carbon dioxide.