Cellular Respiration ✏ Biology In a Nutshell

 Rucete ✏ Biology In a Nutshell

 

 

1. Overview of Cellular Respiration

Cellular respiration is the ATP-generating process that converts glucose into energy.

Overall Equation:

$$\text{Glucose} + O_2 \rightarrow CO_2 + H_2O + ATP$$

• Aerobic respiration occurs in the presence of oxygen.
• ATP is produced through multiple steps, including glycolysis, the Krebs cycle, and oxidative phosphorylation.

 

 

2. Glycolysis (Glucose Breakdown)

• Location: Cytoplasm
• Process: Glucose is broken down into pyruvate while producing ATP.
• Equation: $$\text{Glucose}+2ADP+2Pi+2NA{D}^{+}\to 2\text{Pyruvate}+2ATP+2NADH$$$$\text{Glucose} + 2 ADP + 2 Pi + 2 NAD^+ \rightarrow 2 \text{Pyruvate} + 2 ATP + 2 NADH$$
• ATP Yield: 2 ATP (Net)
  • 4 ATP are produced, but 2 ATP are consumed.

 

 

3. Krebs Cycle (Aerobic Respiration)

• Location: Mitochondrial Matrix
• Process: Pyruvate is converted to Acetyl-CoA, which enters the Krebs cycle.
• Equation for Pyruvate Conversion: $$\text{Pyruvate} + NAD^+ + CoA \rightarrow \text{Acetyl-CoA} + NADH + H^+ + CO_$$
• Steps in the Krebs Cycle:
  1. Acetyl-CoA reacts with oxaloacetate (OAA) to form citrate.
  2. Through multiple reactions, energy carriers and ATP are produced.
• Yield per cycle:
  • 3 NADH, 1 FADH₂, 1 ATP, CO₂ released.
    

 

 

 

4. Oxidative Phosphorylation (ATP Production)

• Location: Inner mitochondrial membrane
• Process:
  • ATP is produced using NADH and FADH₂ from earlier steps.
  • Electrons are passed through the electron transport chain (ETC), and oxygen acts as the final electron acceptor.
• Equation:
  • NADH → 3 ATP
  • FADH₂ → 2 ATP
• Final Electron Acceptor: Oxygen (½ O₂)
• ATP Yield: Most ATP is produced in this stage.

 

 

5. Summary of ATP Yield

Stage	ATP Yield
Glycolysis	2 ATP (net)
Krebs Cycle	2 ATP
Oxidative Phosphorylation	~32-34 ATP
Total ATP (Aerobic Respiration)	~36-38 ATP per glucose molecule

 

 

In a nutshell

"Glycolysis Breaks, Krebs Cycles, Oxygen Powers ATP!"

• Glycolysis = Splits glucose, forms 2 ATP & 2 NADH.
• Krebs Cycle = Acetyl-CoA → NADH, FADH₂, ATP, CO₂.
• Oxidative Phosphorylation = Uses NADH/FADH₂ to produce ATP with oxygen.