Transcript Cellular Respiration - Ursuline High School
Cellular Respiration:
Harvesting Chemical Energy
Respiration is the process of extracting stored energy from glucose to make ATP.
Cellular Respiration Equation C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O and energy As a result of respiration, energy is released from the chemical bonds found in complex organic molecules (food).
Aerobic Respiration
Aerobic Respiration is respiration which takes place in the presence of oxygen
Respiration is controlled by Enzymes …rate is controlled by enzymes
Cell Respiration is divided into 3 stages. (components) 1. Glycolysis 2. Krebs Cycle 3. Oxidative Phosphorylation
Glycolysis
Glyco- glucose, -lysis: to split
Universal step in all forms of respiration
Likely used to supply energy for the ancient cells.
Glycolysis
Function - To split glucose and produce NADH, ATP and Pyruvate (pyruvic acid).
Location - Cytoplasm.
Occurs in 9 steps…. 6 of the steps use magnesium Mg as cofactors.
NAD + Energy carrier
Nicotinamide Adenine Dinucleotide NAD + + 2 e NADH NAD + = oxidized form NADH = reduced form
Requirements for Glycolysis
Glucose
2 ATP…. As activation energy
4 ADP
2 NAD +
Enzymes
The Products of Glycolysis
2 Pyruvic Acids (a 3C acid)
4 ATP
2 NADH
Net Energy Result
2 ATP per glucose
2 NADH
In summary, glycolysis takes one glucose and turns it into 2 pyruvate, 2 NADH and a net of 2 ATP.
Krebs Cycle Also called: Citric Acid Cycle or Tricarboxylic Acid Cycle
Function: Oxidize pyruvic acid to CO 2
Produce: 3NADH, 1FADH 2 and 1ATP
Location: Mitochondria matrix
Formation of Acetyl CoA: Acetyl CoA is formed when the pyruvate , from glycolysis, combines with Coenzyme A… tis takes place in the matrix.
Requirements for Krebs Cycle
Pyruvic acid (3C acid)
Coenzyme A
3 NAD +
1 ADP
1 FAD
Double this list for each glucose.
Products of Krebs Cycle
3 CO 2
Acetyl CoA
3 NADH
1 ATP
1 FADH 2
Double this list for each glucose.
Krebs Cycle
Produces most of the cell's energy in the form of NADH and FADH 2 … not ATP
Does NOT require O 2
The CO 2 produced by the Krebs cycle is the CO 2 animal exhale when they breathe.
Oxidative Phosphorylation
Process of extracting to energy from NADH and FADH ATP.
2 to form
Function: Convert NADH and FADH 2 into ATP.
Location: Mitochondria cristae.
Oxidative Phosphorylation
NADH or FADH 2
ADP
O 2
Oxidative Phosphorylation
Requires the Electron Transport Chain… the Electron Transport Chain is a collection of proteins, embedded in the inner membrane, used to transport the electrons from NADH and FADH 2
Cytochrome c
Cytochrome c: is one of the proteins of the electron transport chain… often used by geneticists to determine relatedness… exists in all living organisms.
The Cytochromes alternate between RED and OX forms and pass electrons down to O 2
ATP Yield
Each NADH energizes 3 ATP
Each FADH 2 energizes 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 through ATP Synthase
ATP Synthase
Uses the flow of H + ATP.
to make
Works like an ion pump in reverse, or like a waterwheel under the flow of H + “water”.
Alcoholic Fermentation
Carried out 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 O 2
Produces ATP when O 2 available.
is not
Lactic Acid Fermentation
Uses only Glycolysis.
An incomplete oxidation energy is still left in the products (lactic acid).
Does NOT require O 2
Produces ATP when O 2 available.
is not
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 O 2 is absent.
Aerobic vs Anaerobic
Aerobic - Respiration with O 2
Anaerobic - Respiration without O 2
Aerobic - All three Respiration steps.
Anaerobic - Glycolysis only.
Strict vs. Facultative Respiration
Strict - can only carry out Respiration one way… aerobic or anaerobic.
Facultative - can switch respiration types depending on O 2 availability. Ex - yeast
ATP yields by Respiration type
Anaerobic - Glycolysis only Gets 2 ATPs per glucose.
Aerobic - Glycolysis, Krebs, and Oxidative Phosphorylation (electron transport chain) Generates many more ATPs per glucose.
Aerobic ATP yield
Glycolysis - 2 ATPS, 2 NADHs
Krebs - 2 ATPS, 8 NADHs, 2 FADH 2
Each NADH = 3 ATP
Each FADH 2 = 2 ATP
ATP Sum
10 NADH x 3 = 30 ATPs
2 FADH 2 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 Respiration; it has 18x more energy per glucose.
But, anaerobic will keep you alive if oxygen is not present.
Importance 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 Gin Barley Saki Grapes Tequila Juniper Cones Vodka Agave Leaves Beer Rice Wine Potatoes 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 CO 2 from fermentation.
Summary
Know the 3 main reactions of Respiration and the 4 required items for each.
Exergonic/Endergonic
Biological Examples
Exergonic - respiration
Endergonic - photosynthesis
Cell - Types of Work
Mechanical - muscle contractions
Transport - pumping across membranes
Chemical - making polymers
Cells use ATP as their energy source
A denosine T ri p hosphate
Made of: - Adenine (nitrogenous base) - Ribose (pentose sugar) - 3 phosphate groups
Phosphates Ribose Adenine
Key to ATP
Is in the high energy bonds between the three phosphate groups.
Negative charges on the phosphate groups repel each other and makes the phosphates unstable.
ATP Cycles
Energy released from ATP drives anabolic reactions.
Energy from catabolic reactions “recharges” ATP.
ATP Cycle ATP ADP + P + Energy
ATP in Cells
A cell's ATP content is recycled every minute.
Humans use close to their body weight in ATP daily.
No ATP production equals quick death.