Lecture Notes: Cellular Respiration
Overview
- Focus on completing cellular respiration
- Photosynthesis to be studied independently
- Two main topics: Cellular Respiration and Photosynthesis
- Chapter 9: Cellular Respiration
- Chapter 10: Photosynthesis
Cellular Respiration
- Definition: Process of making energy in the cell
- Main Stages:
- Glycolysis
- Krebs Cycle (Citric Acid Cycle)
- Electron Transport Chain (ETC)
Glycolysis
- Meaning: Breakdown of glucose
- Process:
- Glucose (6-carbon) is split into two 3-carbon molecules called pyruvate
- Requires initial energy input
- Produces:
- 2 ATP (Net gain - use 2 ATP, make 4 ATP)
- 2 Pyruvate
- 2 NADH (energized form, potential energy)
- Location: Cytoplasm
NAD and NADH
- Roles:
- NAD: Non-energized, oxidized form
- NADH: Energized form, carries hydrogen
- Importance: NADH participates in electron transport chain for energy production
Pyruvate to Acetyl CoA
- Conversion:
- Pyruvate is modified with the addition of vitamin A
- Becomes Acetyl CoA, ready for the Krebs Cycle
- Transport:
- Through mitochondrial membranes using transporters (TIM and TOM)
- Transporter Characteristics:
- Active but can sometimes function without energy
- Subject of scientific studies
Mitochondria Structure
- Components:
- Inner and outer membranes
- Cristae (infoldings)
- Matrix (jelly-like substance)
- Intermembrane Space: Site of hydrogen concentration gradient
Krebs Cycle (Citric Acid Cycle)
- Occurs in: Mitochondrial matrix
- Goals:
- Produce reduced energy carriers: NADH, FADH2
- Generate ATP (small amount)
- Cycle Details:
- Each Acetyl CoA enters the cycle, producing:
- For one glucose molecule (2 turns):
- Waste Product: CO2
Electron Transport Chain (ETC)
- Final Stage: Produces the most ATP
- Location: Cristae of mitochondria
- Process:
- Uses NADH and FADH2 to generate a hydrogen gradient
- ATP produced via chemiosmotic phosphorylation
- Components:
- Protein transporters
- Involves hydrogen transfer across the membrane
- Important Notes:
- Sensitive to poisons like carbon monoxide
Additional Information
- Cellular Poisons: Some affect cycles, e.g., arsenic impacts the Krebs cycle
- Mitochondria and Energy:
- Mitochondria’s role in energy production is crucial
- Has complex biochemistry involving many specific reactions and enzymes
Summary
- Cellular Respiration: Converts glucose to ATP through a series of reactions
- Cycle of Energy: NADH and FADH2 play critical roles as hydrogen carriers
Questions Discussed
- Consumption of ATP directly in the body
- The role of pyruvic acid and pyruvate
- How poison like arsenic affects cellular respiration
These notes review the key points discussed about cellular respiration, emphasizing the biochemical pathways and components involved in ATP production within cells.