1. CELLULAR RESPIRATION (An Introduction)
2.8 & & 8.2

2. The Need for Energy
- all organisms require energy and have evolved to take free energy from the environment and convert it into usable forms
AUTOTROPHS: create their own food (which will later be broken down into usable energy)

3. AUTOTROPHS 1) Photoautotrophs:
Organisms that through photosynthesis convert light energy into chemical potential energy in glucose
ex: green plants

4. Autotrophs.... 2) Chemoautotrophs:
microorganisms the are able to extract energy from inorganic compounds containing elements such as sulphur and iron
usually found in extreme environments such as volcanoes, sulfur springs
Ex: archaebacteria
Sulfolobus acidocaldarius

5. Heterotrophs…
HETEROTROPHS: must consume autotrophs or other heterotrophs in order to gain energy.
Includes the majority of organisms (including all animals and fungi, many protists and bacteria)
all organisms except chemoautotrophs use glucose (C6H12O6) as their primary source of energy.

6. Cellular Respiration
The process of extracting energy from organic, nutrient molecules (i.e. glucose) and storing it into a usable form (ATP) so the cell can use it for energy-requiring activities.
Overall equation:
C6H12O O CO2 + 6 H2O + 36 ATP
oxidized reduced ENERGY

7. Cellular Respiration It is a combustion reaction!
(Glucose is reacted with Oxygen to produce energy)
We will discuss cellular respiration with glucose as our nutrient molecule, however, other carbohydrates, lipids, and proteins can also be used.

8. Adenosine triphosphate

9. ATP
Nitrogen base (Adenine)
3 phosphate groups
Ribose sugar

10. ATP releases energy ATP ADP + Pi + Energy
Phosphate bonds are high energy bonds
Breaking the bonds releases the energy
ATP ADP + Pi + Energy

11. ATP is as Source of Energy
ATP is an energy-containing molecule used to supply the cell with energy.
Many cellular activities require ATP
The synthesis of molecules (such as DNA, RNA, proteins)
Transports of molecules via active transport (i.e., protein pumps such as the Na+/K+ pump
Movement of materials within the cell
Muscle contractions

12. ATP is Recycled ATP is continuously produced and consumed
ATP ADP + Pi + Energy
It is broken down to release energy
ADP and a free phosphate are reconverted into ATP by cellular respiration.
Phosphorylation = attaching a phosphate group to a molecule to make the molecule more unstable and therefore more reactive

13. ATP
When energy from ATP is used in cells, it is ultimately converted into thermal energy (heat)
Remember thermoregulation?
We increase metabolic reactions, such as cellular respiration when we are cold because it generates heat.
While heat can keep an organism warm, it cannot be reused for cell activities

14. Cellular Respiration & Enzymes
There is a lot of energy in a molecule of glucose
In cellular respiration, several enzymes are used to control the breakdown of glucose and to maximize the amount of energy produced and retained in a usable form.

15. Enzymes
Remember, enzymes speed up reactions without actually participating in the reaction.
In a chemical reaction, energy is required for the reaction to proceed and to break apart the bonds of reactant molecules. This is known as the ACTIVATION ENERGY

16. Enzyme
Enzymes speed up the rate of the reaction by lowering the activation energy. (Therefore, the system reaches the required energy level faster)

18. In cellular respiration, heat energy is lost to the environment is reduced because of enzymes!

19. Cellular Respiration is a Redox Reactions
Redox Reactions = Reduction – Oxidation
reactions
Reduction – when a compound gains an electron
Oxidation – when a compound loses an electron.

21. Helpful Memory Tricks: “LEO the lion goes GER”
LEO: Loss of electrons is oxidation
GER: Gain of electrons is reduction
“OIL RIG”
OIL: oxidation is loss (of electrons)
RIG: reduction is gain (of electrons)

22. Example Na + Cl  NaCl Na Cl  [Na]+ [ Cl ]- OXIDIZED REDUCED
(Oxidizing Agent – allows Na to be oxidized)
(Reducing Agent – allows Cl to be reduced)

23. Redox Reactions
During redox reactions, electrons are passed from molecule to molecule in a sequence (moves to more electronegative compounds)
Electronegativity = the measure of an atom’s tendency to attract electrons
As electrons passed along, the molecules will be reduced and oxidized.
This movement of electrons is a from of energy (electrochemical energy) and it can be converted into other forms.

24. Redox Reactions B C- D A- C B- D- A
Increasing electronegativity

25. Energy Transfer Cellular Respiration can be anaerobic or aerobic.
Aerobic Respiration (uses oxygen) and occurs via 2 different energy transfer mechanisms
Substrate-Level Phosphorylation
Oxidative Phosphorylation

26. A) SUBSTRATE LEVEL PHOSPHORYLATION
ATP is produced directly in an enzyme catalyzed reaction.
The enzyme transfers a phosphate group from a substrate molecule (for example PEP) to ADP to make ATP

27. the enzyme allows Pi group to transfer to ADP to make ATP
Page 95 figure 2
the enzyme allows Pi group to transfer to ADP to make ATP

28. B) OXDATIVE PHOSPHORYLATION
ATP is formed indirectly
It is more complex that substrate-level phosphorylation and makes much more ATP
ATP is formed via a series of redox reactions where O2 is the final electron acceptor
The energy released during the redox reactions is used to generate ATP (by phosphorylating ADP)

29. Co-enzymes
Cellular Respiration relies on electron carrier molecules, also known as co-enzymes
These are molecules can accept and give up electrons (so they a reduced and oxidised)
In doing so, they remove electrons from glucose and move them to other areas of the cells and to other more electronegative molecules.

30. Co-enzymes The 2 important co-enzymes in cellular respiration are:
Nicotinamide adenine dinucleotide (NAD)
Flavin adenine dinucleotide (FAD)

31. NAD – Nicotinamide adenine dinucleotide
nicotinamide base phosphates ribose sugar ribose sugar adenine base

32. The Reduction of NAD NAD is reduced by accepting atoms of hydrogen.
Remember : a hydrogen is made of 1 proton and 1 electron
Therefore a hydrogen ion (H+), is really just a proton

33. The Reduction of NAD NAD+ + 2H NADH + H + NAD+ + 2H + + 2é NADH + H +
2 hydrogen atoms are removed from the molecule being reduced
1 hydrogen atom is accepted by NAD+
The other is split into H + and 1é
The é is also accepted by NAD+ to produce NADH
The H + is released
Initially, NAD has a positive charge and exists in its oxidized form
NAD H NADH + H +
oxidized form reduced form
The equation is also written as this:
NAD H + + 2é NADH + H +

34. The Reduction of FAD
FAD is also reduced by the addition of 2 hydrogen atoms
FAD H + + 2é FADH2
oxidized form reduced form

35. Reduction and Oxidation of Co-enzymes
The reduced co-enzymes NADH and FADH2 carries a lot of energy in those gained electrons.
Most of that energy will be used to make ATP

36. Overall 3 goals of cellular respiration:
Break the bonds between 6 carbon atoms (of C6H12O6 ) to make 6 CO2 (convert organic carbon to inorganic carbon)
Move H atom electrons from C6H12O6 to O2 to make 6 H2O
Trap as much free energy as possible in ATP
This is accomplished in 4 mains stages.

37. 4 STAGES of Aerobic Cellular Respiration
GLYCOLYSIS – in cytoplasm
2) PYRUVATE OXIDATION – in mitochondrial matrix
3) KREB CYCLE – in mitochondrial matrix
4) ELECTRON TRANSPORT CHAIN and CHEMIOSMOSIS – inner mitochondrial membrane
Aerobic respiration

39. Annotate a Mitochondrion p387
OUTER MITOCHONDRIAL MEMBRANE
Similar function to cell membrane
Creates a separate compartment with ideal conditions for aerobic respiration
(MITOCHONDRIAL) MATRIX
Inner, fluid filled section
Site of Pyruvate oxidation and the Krebs Cycle
Contain ribosomes and mDNA
INNER MITOCHONDRIAL MEMBRANE
Folded inner membrane, embedded with many proteins for the ETC & Chemiosmosis
INTERMEMBRANE SPACE
- Small, fluid filled space between the inner and outer membranes
CRISTAE
- Folds of the inner membrane which increase surface area for more oxidative phosphorylation