1. Cellular Respiration

2. Question of the Day
How are the products of photosynthesis related to cellular respiration? What organisms undergo cellular respiration?
Products of photosynthesis are the reactants in cellular respiration.
All organisms, including photosynthetic organisms, undergo cellular respiration.

3. Overview of Cellular Respiration
Stage 1 - Glycolysis
Glucose  Pyruvate
Producing NADH and ATP on the side
Stage 2 – Respiration
Requires oxygen to be present
Aerobic respiration:
Take pyruvate and NADH  ton of ATP
Occurs in mitochondria of eukaryotic cells
Occurs in cell membrane in prokaryotic cells
Anaerobic Respiration:
no oxygen needed
Pyruvate  lactate or ethanol and CO2

4. Glycolysis
An enzyme-assisted anaerobic process that breaks down one six-carbon molecule of glucose to two 3-carbon pyruvates
Pyruvate:
Ion of a 3-carbon organic acid (pyruvic acid)
Energy
Glucose breaks down
Hydrogens are transferred to NAD+
NADH electron carrier formed

6. Glycolysis Steps
Phosphate groups from two ATP molecules are transferred to a glucose molecule.
The resulting 6 carbon compound is broken down to two 3 carbon compounds, each with a phosphate group.
2 NADH molecules are produced, and one more phosphate group is transferred to each 2 carbon compound.
Each 3 carbon compound is converted to a 3 carbon pyruvate, producing four ATP molecules in the process

7. Glycolysis Energy Summary
Uses 2 ATP
Produces 4 ATP
Total gain 2 ATP

10. Aerobic Respiration Pyruvate enters mitochondria  Acetyl
Pyruvate = 3 Carbons  Acetyl = 2 Carbons
Products of Conversion = CO2, NADH, Acetyl group
Acetyl Group + coenzyme = compound Acetyl CoA
Krebs cycle
Enzyme-assisted chemical reactions in which acetyl-CoA enters

12. Krebs Cycle Stages
Acetyl CoA + 4C compound  6C compound releasing coenzyme A
CO2 released from 6C compound  5C compound. Electrons transferred to NAD+  NADH
CO2 released from 5C compound  4C compound, also creating ATP and NADH
4C reconfigured releasing. Electrons transferred to FAD  FADH2
4C reconfigured  original cycle starter. NADH produced.

13. Krebs Cycle Summary
NADH and FADH2 contain the energy from glucose and pyruvate
Electron Carriers
4 carbon compound recycled
Acetyl CoA can re-enter the cycle

14. Electron Transport Chain
Inner membrane of mitochondria
NADH and FADH2 contribute electrons
“passed like a ball down a line of people”
Energy used to pump H+ ions out of inner compartment of mitochondria
Concentration gradient formed
Ions diffuse back in through carrier protein
Carrier protein adds phosphates to ADP = ATP
Oxygen molecules form with Hydrogens = Water
Oxygen is the final electron acceptor

15. Anaerobic Respiration
When no oxygen is present we have no final electron acceptor
Instead the electrons from NADH are transferred to pyruvate (taken from glycolysis)
NAD+ recycled, ATP made
Organic hydrogen acceptor used instead of Oxygen
Fermentation

16. Types of fermentation in Anaerobic Respiration
Lactic Acid Fermentation
Used by some bacteria and fungi to make foods like yogurt and cheeses
3C pyruvate  Lactate ion used from organic lactic acid
Lets glycolysis continued making ATP as long as the supply of glucose remains.
Alcoholic Fermentation
Yeast used to make wine and beer
3C pyruvate  2C compound releasing CO2
Electrons NADH + 2C compound  ethanol