Download Chapter 9 Cellular Respiration

Monday, October 27
• Label the diagram
Is this a process of turning food
into energy?
Rs - Equation
C6H12O6 + 6 O2
6 CO2 + 6 H2O
and energy
The energy is released from the chemical
bonds in the complex organic molecules.
Respiration - Preview
• The process of releasing Energy from
food.
• Food - Stored Energy in
chemical bonds.
• ATP - Useable Energy for cell
work.
Focus of Chapter
1. Purpose - what is the reaction
suppose to do?
2. Location - where is it at?
3. Requirements - what is needed to
make it run?
4. Products - what does it produce?
Oxidation - definitions
• Loss of electrons.
• Loss of energy.
• Loss of Hydrogens from Carbons.
Reduction - definitions
• Gain of electrons.
• Gain of energy.
• Gain of Hydrogens to Carbons.
Comment - be careful not to use “reduction”
in lay terms.
Redox reactions
Redox reactions
• Reactions are usually paired or linked
together.
• Look for these links as we study Rs.
• Many of the reactions will be done by
phosphorylation
Phosphorylation
• Adding a phosphate group to a molecule.
• The phosphate group adds “energy” to the
molecule for chemical reactions.
Phosphorylation
Cell Respiration - parts
1. Glycolysis
2. Krebs Cycle
3. Electron Transport Chain
Glycolysis
•
•
•
•
Glyco- glucose.
-lysis: to split
Universal step in all Rs types.
Likely to earliest type of cell energy
processes.
Glycolysis
• Function - To split glucose and produce
NADH and ATP.
• Location - Cytoplasm.
Electron Carrier Compounds
• Molecules that transport or shuttle
electrons within the cell.
• Exist it two forms:
• Oxidized (ox)
• Reduced (red)
NAD
• Nicotinamide Adenine Dinucleotide
NAD+ + 2 eNADH
NAD+ = oxidized form
NADH = reduced form
•
•
•
•
Glycolysis -Requirements
Glucose
2 ATP
4 ADP
2 NAD+
Glycolysis - Products
•
•
•
•
2 Pyruvic Acids (a 3C acid)
2 ADP
4 ATP
2 NADH
Net Result
• 2 ATP per glucose
• 2 NADH
Energy Investment Phase
Energy Harvest Phase
Tuesday, October 28
• Calculate the rate change of the reaction from
its initial rate to its rate after 120 seconds.
Explain why there is no further increase in
product after 100 seconds. Predict what
happens if more enzyme is added after 100
seconds. Predict what happens if more
substrate is added after 100 seconds.
Time (s)
0
20
40
60
80
100
120
Product
(ug)
0
0.25
0.5
0.7
0.8
0.85
0.85
Krebs Cycle
• Also called:
• Citric Acid Cycle
• Tricarboxylic Acid Cycle
Krebs Cycle
• Function: Oxidize pyruvic acid to CO2
• Produce NADH and FADH2
• Location: Mitochondria matrix
Formation of Acetyl CoA
Krebs Cycle -Requirements
•
•
•
•
•
•
Pyruvic acid (3C acid)
Coenzyme A
4 NAD+
1 ADP
1 FAD
Double this list for each glucose.
Krebs Cycle - Products
•
•
•
•
•
•
3 CO2
Acetyl CoA
4 NADH
1 ATP
1 FADH2
Double this list for each glucose.
Krebs Cycle
• Produces most of the cell's energy in the
form of NADH and FADH2
• Does NOT require O2
Comment
• The ATPs produced directly in Krebs
Cycle and in Glycolysis are by:
• Substrate-level phosphorylation
• The Pi group is transferred from a
substrate to ADP.
Electron Transport Chain
• ETC or Electron Transport System (ETS).
• A collection of proteins that are structurally
linked into units.
ETC
• Uses sets of Cytochromes, Fe containing
proteins to pass electrons.
• The Cytochromes alternate between RED
and OX forms and pass electrons down
to O2
ETC
• Function: Convert NADH and FADH2 into
ATP.
• Location: Mitochondria cristae.
ETC - Requirements
• NADH or FADH2
• ADP
• O2
ETC - Products
• NAD+ and FAD
• ATP
• H 2O
ETC - ATP Yields
• Each NADH -- 3 ATP
• Each FADH2 -- 2 ATP
Chemiosmotic Hypothesis
• ETC energy is used to move H+ (protons)
across the cristae membrane.
• ATP is generated as the H+ diffuse back
into the matrix.
ATP Synthase
• Uses the flow of H+ to make ATP.
• Works like an ion pump in reverse, or like
a waterwheel under the flow of H+ “water”.
ATP Synthase Animation
• http://www.youtube.com/watch?v=PjdPTY
1wHdQ
• You may also wish to watch other
animations at Youtube.
Wednesday, October 29
• For each step below, A, B, and C, identify
the name of the process. Then, state the
location where the process takes place in
the cell. Describe each step in term of
ATP production.
Alcoholic Fermentation
• Done by yeast, a kind of fungus.
Alcoholic Fermentation
• Uses only Glycolysis.
• An incomplete oxidation - energy is still
left in the products (alcohol).
• Does NOT require O2
• Produces ATP when O2 is not available.
Lactic Acid Fermentation
• Uses only Glycolysis.
• An incomplete oxidation - energy is still
left in the products (lactic acid).
• Does NOT require O2
• Produces ATP when O2 is not available.
Lactic Acid Fermentation
• Done by human muscle cells under
oxygen debt.
• Lactic Acid is a toxin and causes soreness
and stiffness in muscles.
Fermentation - Summary
• Way of using up NADH so Glycolysis can
still run.
• Provides ATP to a cell even when O2 is
absent.
Aerobic vs Anaerobic
•
•
•
•
Aerobic - Rs with O2
Anaerobic - Rs without O2
Aerobic - All three Rs steps.
Anaerobic - Glycolysis only.
Strict vs. Facultative
• Strict - can only do Rs this one way.
• Facultative - can switch Rs types
depending on O2 availability. Ex - yeast
Question
• Since yeast can do both aerobic and
anaerobic Rs, which is the better process
if given a choice?
• Check the ATP yields from both
processes.
ATP yields by Rs type
• Anaerobic - Glycolysis only Gets 2 ATPs
per glucose.
• Aerobic - Glycolysis, Krebs, and ETC.
Generates many more ATPs per glucose.
Aerobic ATP yield
•
•
•
•
Glycolysis - 2 ATPS, 2 NADHs
Krebs - 2 ATPS, 8 NADHs, 2 FADH2
Each NADH = 3 ATP
Each FADH2 = 2 ATP
ATP Sum
• 10 NADH x 3 = 30 ATPs
• 2 FADH2 x 2 =
4 ATPs
• 2 ATPs (Gly) = 2 ATPs
• 2 ATPs (Krebs) = 2 ATPs
• Max = 38 ATPs per glucose
However...
• Some energy is used in shuttling the
NADH from Glycolysis into the
mitochondria.
• Actual ATP yield ~ 36/glucose
Yeast
• Would rather do aerobic Rs; it has 18x
more energy per glucose.
• But, anaerobic will keep you alive if
oxygen is not present.
Importance of Rs
• Convert food to ATP.
• Provides materials for use in other cellular
pathways.
Other Importances of Respiration
• Alcohol Industry - almost every society
has a fermented beverage.
• Baking Industry - many breads use yeast
to provide bubbles to raise the dough.
Matching
Sugar Cane
Barley
Grapes
Juniper Cones
Agave Leaves
Rice
Potatoes
Gin
Saki
Tequila
Vodka
Beer
Wine
Rum
Question
• Why is the alcohol content of wine always
around 12-14%?
• Alcohol is toxic and kills the yeast at high
concentrations.
Swiss Cheese
• Holes are bubbles of CO2 from
fermentation.
Summary
• Know the 3 main reactions of Rs and the 4
required items for each.
• Appreciate the importances of Rs.
Regulation
• AMP
Stimulates
• ATP and
Citrate Inhibits
Rs - Equation
C6H12O6 + 6 O2
6 CO2 + 6 H2O
and energy
Which part of the equations represent which
of the 3 Rs reactions?