Learn: Cellular Respiration
Lecture Goals:
- Examine cellular metabolism and its components
- Understand mechanisms of biological reactions
- Examine energy transfer from the breakdown of food
- Be able to explain what cellular respiration is and how it functions
Course Competencies:
8. Compare and contrast prokaryotic and eukaryotic cells. (III)
11. Describe the laws of thermodynamics and their relationship to the energy dynamics of living things. (V) 12. Explain the importance of enzymes to metabolic processes and their mode of action. (V)
13. Explain the importance of adenosine triphosphate (ATP) to living things. (V)
14. Explain the importance of cellular respiration and describe the steps in its metabolic pathway. (VI)
Presentation Links
Day 1
Glycolysis
History of Respiration and Oxygen
Intro to Cellular Respiration
Intro to Pyruvate
Review of Energy
Day 2
Electron Transport Chain
Fermentation
Citric Acid Cycle
Review of Energy Terms
- Recall Theme of Life: Life Depends on a continuous input and transfer of energy
- Energy cannot be created or destroyed.
- Redox Reaction
- Occurs within covalent bonds:
- Oxidation is when an atom "loses" an electron
- Reduction is when an atom "gains" an electron
- Energy is transferred through electron exchange
Review of Energy Terms
- Endergonic Reactions
- positive∆G and consequently use energy
- anabolic processes are endergonic reactions
- Exergonic Reactions
- negative ∆G and consequently release energy
- catabolic processes are exergonic reactions.
Cellular Respiration
"When life hands you sugar, make energy!"
- Cellular Respiration
- a series of metabolic pathways extracts the energy from the bonds in glucose and converts it into ATP and similar energy storing molecules.
- Exergonic reaction
- Full process varies on organism
- Eukaryotic cellular respiration contains anaerobic and aerobic parts (overall, C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O)
- Some (not all) prokaryotic cellular respiration is strictly anaerobic (called obligate anerobes)
Test your Knowledge
History of Respiration and Oxygen
Oxygen and the First Mass Extinction
- Oxygen occurred at very low levels early in Earth's history
- This is due to the temperature of earth's formation. The heat present causes oxygen to bond into CO2 or into other minerals, but not as O2.
- Interesting note: The presence of O2 blocks particular colors of infrared. This has the potential of being observed when viewing planets outside of our solar system. This is how astronomers identify planets that may have life.
History of Respiration and Oxygen
Oxygen and the First Mass Extinction
- Early life
- Earliest prokaryotic cells show in the fossil record around 3.8bya
- Oxygen wasn't present in measurable concentrations until 2.7bya
- Early respiration was anaerobic.
- Early autotrophs were using chemosynthesis
History of Respiration and Oxygen
Oxygen and the First Mass Extinction
- Cyanobacteria
- Early photosynthesizers
- Produced oxygen as a waste product
- Their respiration was anaerobic
- Resulted in the "Great Oxidation Event"
- Resulted in the first mass extinction
History of Respiration and Oxygen
Oxygen and the First Mass Extinction
Resulted in the first mass extinction... Why?Discuss with your group and create a hypothesis as to why oxygen may have caused a mass extinction. Consider things like the properties of oxygen (especially in terms of electron hogging), activation energy, exergonic or endergonic reactions, etc.
History of Respiration and Oxygen
Optional Reading: Oxygen and Anaerobes
Check your notes
Explain the following to your neighbor:
- cellular respiration
- aerobic
- anaerobic
02:00
Glycolysis
The Breaking of Glucose
- Glycolysis
- "gluco" means sugar, "lysis" means breaking
- anaerobic
- used by many types of cells
- prokaryotic
- mammalian red blood cells
Glycolysis
Overview
- Has an activation energy of two ATP
- Produces four ATP, two NADH, and two Pyruvate
Glycolysis
Details: Part 1
The two three-carbon molecules start off as different types of compounds but are converted to the same in preparation of the next step
This makes it possible for enzymes to split the ring, which is normally strong/stable
Energy is added to the molecule through a phosphate group (from ATP)
Key Steps:
Glycolysis
Details: Part 2
Key Steps:
A second phosphate group is added from NADP converting it to NADH. This will be used in a different reaction.
It takes several reactions to remove the two phosphate groups. Their energy is stored in ATP. Water is released as part of this. The final molecule without phosphate is pyruvate.
This part of the pathway happens twice. Once for each 3-carbon sugar.
Glycolysis
All Steps Visualized
Check your notes
Using the provided whiteboards, work with your group to draw the 10 steps of glycolysis. Label where ATP is used and where ATP, NADH, and Pyruvate are produced. Make note of where dehydration synthesis or hydrolysis occurs.
05:00
Pyruvate (and NADH)
The next steps of energy acquisition
- Glycolysis alone is a very inefficient process
- only two net ATP produced (four made, two used)
- Pyruvate
- Anaerobic
- Aerobic:
- breakdown of pyruvate
- Citric Acid Cycle
Test your Knowledge
Re-play game ID: 03759239URL: https://kahoot.it/challenge/03759239?challenge-id=3949a59a-8d09-460e-9e4a-705131af1208_1708547933805
Kahoot! live game will be played during class. Game will become available for replay after class.
Fermentation
Anaerobic processing of pyruvate
- Lactic Acid
- used by red blood cells and some prokaryotes (like those in yogurt)
- Pyruvic acid+NADH ↔ lactic acid+NAD+
- two-way reaction that is restricted by pH
- Alcohol Fermentation
- this is how we make bread and alcoholic drinks, with the help of our microbial friends (many yeasts and prokaryotes use this method)
- pyruvic acid + H+ → CO2+ acetaldehyde + NADH+ H+ →ethanol+ NAD+
Fermentation
Anaerobic processing of pyruvate
Test Your Knowledge
Work with your group to explain how bread is made and how that relates to anaerobic energy processing
03:00
Citric Acid Cycle
Aerobic processing of pyruvate
- Occurs in the Mitochondria
- Pre-step: The breakdown of pyruvate
- Results in the creation of Acetyl CoA and additional NADH
- Acetyl CoA is also part of the breakdown of lipids and proteins (in addition to carbohydrates)
- This allows for efficiency in energy production
Citric Acid Cycle
You are here
Aerobic processing of pyruvate
- Citric Acid Cycle (also known as the TCA cycle and the Krebs cycle)
- Occurs in the matrix of the mitochondria
- Produces ATP (two), NADH, and FADH2
- Provides the material for the Electron Transport Chain
- produces large amounts of ATP using NADH and FADH2
Citric Acid Cycle
All Steps
Citric Acid Cycle
Key Steps:
This occurs twice per glucose molecule, due to two pyruvate forming two acetyl CoA. The acetyl CoA, which came from pyruvate, is used up in the reaction.
This is a cycle due to oxaloacetate being replenished.
Water is used in multiple steps of the cycle.
Energy is transferred to carrier molecules, primarily NADH and FADH2. In the first two instances of NADH forming CO2 is released as a biproduct. Only one ATP is formed per turn of the cycle.
Citric Acid Cycle
All Steps Visualized
Check your notes
Using the provided whiteboards, work with your group to draw the steps of citric acid cycle. Label where ATP, NADH, and FADH2 are produced.
05:00
You are here
Electron Transport Chain
Overview
H+
H+
H+
H+
H+
H+
H+
H+
H+
Intermembrane Space
e-
e-
Inner Mitochondrial Membrane
H+
e-
e-
H+
e-
H+
e-
O2
Matrix
FADH
ATP
H+
H+
NADPH
H+
H+
H20
https://www.youtube.com/watch?v=hj_WKgnL6MI
Electron Transport Chain
Step 1: Energy (e-) from NADH and FADH2 is used to pump protons creating a concentration gradient
H+
H+
H+
H+
Intermembrane Space
e-
Inner Mitochondrial Membrane
H+
e-
e-
Matrix
FADH
H+
NADPH
H+
https://www.youtube.com/watch?v=hj_WKgnL6MI
Electron Transport Chain
The electrons are carried to oxygen, which splits and binds to two protons (H+) to create water.
Intermembrane Space
e-
e-
Inner Mitochondrial Membrane
e-
H+
e-
O2
Matrix
H+
H+
H20
https://www.youtube.com/watch?v=hj_WKgnL6MI
Electron Transport Chain
H+
H+
Due to the concentration gradient, protons pass through ATP Synthase. This causes it to spin and attach phosphate groups to ADP forming ATP. This is where most ATP is synthesized. It produces approximately 32 ATP per glucose molecule.
H+
H+
H+
H+
H+
H+
H+
H+
ATP
H+
H+
https://www.youtube.com/watch?v=hj_WKgnL6MI
You are here
Electron Transport Chain
All Steps
H+
H+
H+
H+
H+
H+
H+
H+
H+
Intermembrane Space
e-
e-
Inner Mitochondrial Membrane
H+
e-
e-
H+
e-
H+
e-
O2
Matrix
FADH
ATP
H+
H+
NADPH
H+
H+
H20
https://www.youtube.com/watch?v=hj_WKgnL6MI
Electron Transport Chain
All Steps Visualized
Aerobic Respiration by the Numbers
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O 36ADP + 36Pi → 36ATP Thinking about mass and energy: Where do they come from and where do they go?
Check your notes
Using the provided whiteboards, work with your group to draw the steps of the Electron Transport Chain.Return to the previous steps and based on how much NADH and FADH2 is produced, determine how many ATP is made at this step.
07:00
Test your Knowledge
Re-play game ID: 03759239URL: https://kahoot.it/challenge/03759239?challenge-id=3949a59a-8d09-460e-9e4a-705131af1208_1708547933805
Kahoot! live game will be played during class. Game will become available for replay after class.
9IP Cellular Respiration
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Transcript
Learn: Cellular Respiration
Lecture Goals:
Course Competencies: 8. Compare and contrast prokaryotic and eukaryotic cells. (III) 11. Describe the laws of thermodynamics and their relationship to the energy dynamics of living things. (V) 12. Explain the importance of enzymes to metabolic processes and their mode of action. (V) 13. Explain the importance of adenosine triphosphate (ATP) to living things. (V) 14. Explain the importance of cellular respiration and describe the steps in its metabolic pathway. (VI)
Presentation Links
Day 1
Glycolysis
History of Respiration and Oxygen
Intro to Cellular Respiration
Intro to Pyruvate
Review of Energy
Day 2
Electron Transport Chain
Fermentation
Citric Acid Cycle
Review of Energy Terms
Review of Energy Terms
Cellular Respiration
"When life hands you sugar, make energy!"
Test your Knowledge
History of Respiration and Oxygen
Oxygen and the First Mass Extinction
History of Respiration and Oxygen
Oxygen and the First Mass Extinction
History of Respiration and Oxygen
Oxygen and the First Mass Extinction
History of Respiration and Oxygen
Oxygen and the First Mass Extinction
Resulted in the first mass extinction... Why?Discuss with your group and create a hypothesis as to why oxygen may have caused a mass extinction. Consider things like the properties of oxygen (especially in terms of electron hogging), activation energy, exergonic or endergonic reactions, etc.
History of Respiration and Oxygen
Optional Reading: Oxygen and Anaerobes
Check your notes
Explain the following to your neighbor:
02:00
Glycolysis
The Breaking of Glucose
Glycolysis
Overview
Glycolysis
Details: Part 1
The two three-carbon molecules start off as different types of compounds but are converted to the same in preparation of the next step
This makes it possible for enzymes to split the ring, which is normally strong/stable
Energy is added to the molecule through a phosphate group (from ATP)
Key Steps:
Glycolysis
Details: Part 2
Key Steps:
A second phosphate group is added from NADP converting it to NADH. This will be used in a different reaction.
It takes several reactions to remove the two phosphate groups. Their energy is stored in ATP. Water is released as part of this. The final molecule without phosphate is pyruvate.
This part of the pathway happens twice. Once for each 3-carbon sugar.
Glycolysis
All Steps Visualized
Check your notes
Using the provided whiteboards, work with your group to draw the 10 steps of glycolysis. Label where ATP is used and where ATP, NADH, and Pyruvate are produced. Make note of where dehydration synthesis or hydrolysis occurs.
05:00
Pyruvate (and NADH)
The next steps of energy acquisition
Test your Knowledge
Re-play game ID: 03759239URL: https://kahoot.it/challenge/03759239?challenge-id=3949a59a-8d09-460e-9e4a-705131af1208_1708547933805
Kahoot! live game will be played during class. Game will become available for replay after class.
Fermentation
Anaerobic processing of pyruvate
Fermentation
Anaerobic processing of pyruvate
Test Your Knowledge
Work with your group to explain how bread is made and how that relates to anaerobic energy processing
03:00
Citric Acid Cycle
Aerobic processing of pyruvate
Citric Acid Cycle
You are here
Aerobic processing of pyruvate
Citric Acid Cycle
All Steps
Citric Acid Cycle
Key Steps:
This occurs twice per glucose molecule, due to two pyruvate forming two acetyl CoA. The acetyl CoA, which came from pyruvate, is used up in the reaction.
This is a cycle due to oxaloacetate being replenished.
Water is used in multiple steps of the cycle.
Energy is transferred to carrier molecules, primarily NADH and FADH2. In the first two instances of NADH forming CO2 is released as a biproduct. Only one ATP is formed per turn of the cycle.
Citric Acid Cycle
All Steps Visualized
Check your notes
Using the provided whiteboards, work with your group to draw the steps of citric acid cycle. Label where ATP, NADH, and FADH2 are produced.
05:00
You are here
Electron Transport Chain
Overview
H+
H+
H+
H+
H+
H+
H+
H+
H+
Intermembrane Space
e-
e-
Inner Mitochondrial Membrane
H+
e-
e-
H+
e-
H+
e-
O2
Matrix
FADH
ATP
H+
H+
NADPH
H+
H+
H20
https://www.youtube.com/watch?v=hj_WKgnL6MI
Electron Transport Chain
Step 1: Energy (e-) from NADH and FADH2 is used to pump protons creating a concentration gradient
H+
H+
H+
H+
Intermembrane Space
e-
Inner Mitochondrial Membrane
H+
e-
e-
Matrix
FADH
H+
NADPH
H+
https://www.youtube.com/watch?v=hj_WKgnL6MI
Electron Transport Chain
The electrons are carried to oxygen, which splits and binds to two protons (H+) to create water.
Intermembrane Space
e-
e-
Inner Mitochondrial Membrane
e-
H+
e-
O2
Matrix
H+
H+
H20
https://www.youtube.com/watch?v=hj_WKgnL6MI
Electron Transport Chain
H+
H+
Due to the concentration gradient, protons pass through ATP Synthase. This causes it to spin and attach phosphate groups to ADP forming ATP. This is where most ATP is synthesized. It produces approximately 32 ATP per glucose molecule.
H+
H+
H+
H+
H+
H+
H+
H+
ATP
H+
H+
https://www.youtube.com/watch?v=hj_WKgnL6MI
You are here
Electron Transport Chain
All Steps
H+
H+
H+
H+
H+
H+
H+
H+
H+
Intermembrane Space
e-
e-
Inner Mitochondrial Membrane
H+
e-
e-
H+
e-
H+
e-
O2
Matrix
FADH
ATP
H+
H+
NADPH
H+
H+
H20
https://www.youtube.com/watch?v=hj_WKgnL6MI
Electron Transport Chain
All Steps Visualized
Aerobic Respiration by the Numbers
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O 36ADP + 36Pi → 36ATP Thinking about mass and energy: Where do they come from and where do they go?
Check your notes
Using the provided whiteboards, work with your group to draw the steps of the Electron Transport Chain.Return to the previous steps and based on how much NADH and FADH2 is produced, determine how many ATP is made at this step.
07:00
Test your Knowledge
Re-play game ID: 03759239URL: https://kahoot.it/challenge/03759239?challenge-id=3949a59a-8d09-460e-9e4a-705131af1208_1708547933805
Kahoot! live game will be played during class. Game will become available for replay after class.