Cellular Respiration Flashcards
What is Cellular Respiration?
• Cellular respiration is the process by which cells extract energy from nutrients, primarily glucose.
• One method of energy extraction is through redox reactions, where electrons are transferred from glucose to oxygen.
• Glucose is oxidized to CO₂ (it loses electrons).
• Oxygen is reduced to H₂O (it gains electrons).
General glucose and oxygen redox reaction
Glucose - C6 H12 O6 ~> CO2
Oxygen - O2 ~> H2O
C6H12O6 + 6O2 ~> CO2 + H2O + ATP
What is aerobic respiration?
• It is a process that requires oxygen to break down glucose and produce ATP
• Cellular respiration is aerobic
What is obligate aerobes?
Organisms that require O2
What is obligate anaerobes?
Organisms that must sustain metabolism without O2
What are autotrophs?
Organisms that make their own energy (e.g., plants via photosynthesis).
What are heterotrophs?
Organisms that depend on others for energy (e.g., animals, fungi).
What is ATP?
ATP (Adenosine Triphosphate): is a molecule that stores and releases energy from chemical bonds. This energy is used for cellular activity
What are the 4 stages of cellular respiration and their locations?
• Glycolysis – Cytosol (liquid surrounding organelles)
• Pyruvate Oxidation – Mitochondrial matrix (innermost part of mitochondrion)
• Krebs Cycle (Citric Acid Cycle) – Mitochondrial matrix
• Electron Transport Chain & Chemiosmosis – Inner mitochondrial membrane
What are the two ways ADP makes ATP?
- Substrate-Level Phosphorylation
- Oxidative Phosphorylation
What’s ATP and ADP
• ATP (Adenosine Triphosphate) = High energy molecule with 3 phosphate groups.
• ADP (Adenosine Diphosphate) = Low energy molecule with 2 phosphate groups, converted to ATP during energy transfer
What is substrate level phosphorylation?
• It is a process which forms ATP in an enzyme reaction. An high energy energy (substrate) reaction with ADP, transferring an additional phosphate group, forming ATP.
• This process occurs in the glycolysis cycle (4 ATP) and the kerbs cycle (2 ATP)
What is Oxidative Phosphorylation?
• ATP is formed indirectly through energy released by molecules in stages 1-4 of cellular respiration.
• NAD+ turns into NADH (when it gains energy).
• FAD turns into FADH₂ (when it gains energy).
• In stage 4 (Electron Transport Chain & Chemiosmosis), energy from NADH and FADH₂ is used to produce ATP.
• Occurs in the inner mitochondrial membrane.
