1. Cellular Respiration
The Energy in Food

2. The Energy in Food
Cellular Respiration – A chemical process that uses oxygen to convert the chemical energy stored in foods (organic molecules) into another form of chemical energy.
ATP – Adenosine Triphosphate
Cells in plants and animals use ATP as their main energy supply

3. The Energy in Food Rapid Oxidation – the release of chemical energy by
burning
This reaction is not controlled by enzymes
Results consist of an uncontrolled energy release

4. The Energy in Food Slow Oxidation – the release of energy
in a controlled fashion.
Enzymes catalyze a sequence of events that cause covalent bonds to break one at a time.
This is Metabolism!

5. Photosynthesis / Cellular Respiration
Recycle a common set of chemicals:
Water
Carbon Dioxide
Oxygen
Glucose (Organic Compounds)

7. ATP Phosphate part is most important
Because of the negative charge on all the attached oxygens, there is a lot of potential energy in these bonds
Removing the last phosphate group makes the molecule much “happier” (chemically stable)

8. ATP to ADP
“renewable” molecule; ATP ADP, energy to do this comes from food you eat

9. Three Types of work that Cells Perform “Review”
Chemical Work
Building large molecules like proteins
ATP provides energy for Dehydration Synthesis

10. Three Types of work that Cells Perform “Review”
Mechanical Work
Muscle Contraction
ATP causes change in shape of protein which then opens the door for Potassium (K) and Calcium (Ca) to cause the binding of Actin and Myosin.

11. Three Types of work that Cells Perform “Review”
Transport Work
Pumping Ions across a membrane

12. Respiration
Organic compounds contained stored (potential) chemical energy in their bonds
When that energy is released, cells can use it for metabolism
Glucose (from glycogen stores) typically used first as the source of energy
No glucose? Lipids next
then amino acids/proteins (only in extreme cases- i.e. starvation)

13. Respiration Glycolysis is the first step in respiration
Controlled release of energy from organic compounds in cells to form:
Adenosine Triphosphate (ATP)
Glycolysis is the first step in respiration
Two types of respiration:
Aerobic (uses oxygen)
Anaerobic (without oxygen)
2 types of anaerobic respiration:
Lactic Acid Fermentation (Humans / Mammals)
Alcoholic Fermentation (yeast)

14. Anaerobic Respiration Lactic Acid Fermentation
Normally in aerobic organisms that find themselves in a situation where oxygen is no longer available—why you breather harder when you work out
Pyruvate converted to lactate (3-C), no CO2 produced, no ATP produced
When O2 becomes available, lactate converted back to pyruvate and then pushed through the aerobic pathway

15. Anaerobic Respiration Lactic Acid Fermentation
DOES NOT MAKE YOU SORE
NO ATP IS MADE SO IT DOES CAUSE FATIGUE

16. Anaerobic Respiration Alcoholic Fermentation
Occurs in yeast cells
This is a “normal” situation for the yeast
Pyruvate converted to ethanol (2-C) and CO2 is released…both waste products for the organism
Bakers’ and brewers’ yeast allows bread to rise and beer to be carbonated (most commercial beer is forcibly carbonated as well)

17. Fermentation in Microorganisms

18. Oxygen and Cellular Respiration
Breathing and Cellular Respiration
Aerobic Process – means it requires
oxygen
Cells Exchange:
Oxygen into the cell
Carbon Dioxide out of the cell
Body: In your lungs – Blood Exchange:
Oxygen (in)
Carbon Dioxide (out)

19. Cellular Respiration Chemical Formula:
Each glucose molecule yields 38 ATP molecules

20. Reviewing the Mitochondria
Found in almost all Eukaryotic Cells
The Mitochondria structure is key to its role in cellular respiration
Have their own DNA
Have their own
ribosomes

21. Mitochondria Structure: Made – up of two membranes
There is a space between the inner and the outer membrane
Matrix – the highly folded inner membrane
enclosing a thick fluid
Inside the inner membrane you find many of the enzymes involved in cellular respiration
folds of the membrane allows a Large Surface Area for reactions to occur.
MAXIMIZES the area for ATP production

22. Cellular Respiration First:
Metabolism – all chemical processes in a cell
Metabolic Pathways – Term given to cellular
respiration; because it is
made up of a series of
reactions (thus the term
pathways)
Specific enzymes catalyzes each reactions in a pathways

23. The Metabolic Pathways
Three Steps or Stages
Stage 1: Glycolysis = “Splitting Sugar”
First stage in breaking down glucose molecule
Takes PLACE outside the mitochondria in the cytoplasm
2 ATP molecules are actually used to get things started.
2 ATP’s split the glucose molecule in half.
Investment Stage
Electrons are then transferred to a carrier molecule called NAD
NAD then turn into NADH
At this point 4 ATP are produced
Now your up by 2 ATP

24. The Metabolic Pathways
Glycolysis (Payback Stage)
Remember you used 2 ATP’s to start
Gained 4 (net gain)
End Result are:
Two Pyruvic Acid Molecules
Glucose + 2ATP Pyruvic Acid molecules
+ 4ATP
Pyruvic Acid Molecules still hold most of the energy of the original glucose molecules

25. The Metabolic Pathways
Stage 2: The Kreb Cycle
Named after biologist Hans Krebs
Blame this guy

26. The Metabolic Pathways
The Kreb Cycle
Finishes the breakdown of Pyruvic Acid molecules to CO₂ - releasing more energy.
Pyruvate loses a C as CO2, becomes acetyl-CoA
Enzymes are dissolved in the Matrix inside the Matrix
Called the Fluid Matrix

27. The Metabolic Pathways
The Kreb Cycle
Acetyl Co A joins a 4 Carbon Acceptor molecule
Produces 2 CO₂ + 1 ATP per Acetyl CoA
NADH and FADH₂ (another electron carrier) trap most of the energy
At the end you are left with a 4 carbon acceptor molecule
So the cycle can continue

28. The Metabolic Pathways

29. The Metabolic Pathways
The Kreb Cycle
Results:
Glycolysis produces 2 Pyruvic Acid molecules from 1 glucose molecule
Each Pyruvic Acid molecule makes 1 Acetyl CoA
Cycle turns 2 TIMES
Producing: 4 CO₂ + 2ATP’s

30. The Metabolic Pathways
Electron Transport Chain & ATP Synthase Action
First: (carrier molecules) NADH transfers electrons from the original glucose molecule to an electron transport chain.
Remember: eˉ move to carriers that attract them more strongly
This is why they move from carrier to carrier
One carrier attracts them more than the one carrying; moving the eˉ to the inner mitochondria
Finally being pulled by oxygen at the end of the chain.
2 H⁺ combines with oxygen forming H₂O

31. The Metabolic Pathways Electron Transport Chain & ATP Synthase Action

32. The Metabolic Pathways Electron Transport Chain & ATP Synthase Action
ATP Synthase – Protein structures inside the mitochondria that receives the H⁺ uses that flow to convert ADP into ATP.
Can make up to 34 ATP’s

33. Electron Transport Chain 34 ATP
The Final Count
Glycolysis 2 ATP
Kreb Cycle 2 ATP
Electron Transport Chain 34 ATP
Maximum ATP for 1 Glucose Molecule = 38
Notice most ATP is made after Glycolysis and Kreb Cycle – which are anaerobic (without O₂)

34. Aerobic respiration

35. Anaerobic Respiration
Types of Respiration
Anaerobic Respiration
Aerobic Respiration
Occurs in the absence of Oxygen
Occurs in presence of Oxygen
Occurs in the cells’ cytoplasm
Occurs in the cells’ mitochondria
Yields small amount of ATP (2 molecules) per molecule of glucose
Yields large amount of ATP (38 molecules) per molecule of glucose
Involves fermentation of pyruvate to lactate in muscles/CO2 & ethanol in plant & yeast
Does not involve fermentation

36. Comparison between Aerobic & Anaerobic Respiration -Animals