Mitochondria ✏ Biology In a Nutshell

Rucete ✏ Biology In a Nutshell

1. What is the Mitochondria?

 

• The organelle responsible for aerobic respiration.
• The site of ATP production through the Krebs cycle and oxidative phosphorylation.
• Often called the "powerhouse of the cell" because it generates energy.

2. Structure of Mitochondria

Structure	Function
Outer Membrane	Phospholipid bilayer that encloses the mitochondria.
Inner Membrane (Cristae)	Contains the electron transport chain (ETC) and is where oxidative phosphorylation occurs.
Matrix	Fluid-filled space inside mitochondria. Site of the Krebs cycle and pyruvate conversion to Acetyl-CoA.
Intermembrane Space	Accumulates H⁺ ions (protons), creating a gradient used in ATP production.

3. Chemiosmosis in Mitochondria

Chemiosmosis is the mechanism for ATP production driven by a proton gradient.

Steps of Chemiosmosis:

1. The Krebs cycle in the matrix produces NADH and FADH₂.
2. Electrons are removed from NADH and FADH₂.
3. H⁺ ions (protons) are pumped from the matrix into the intermembrane space.
4. This creates a pH and voltage (electrical) gradient across the inner membrane.
5. ATP Synthase uses this gradient to produce ATP.
   

4. In a Nutshell - Mitochondrial Function

• Krebs Cycle & Pyruvate Processing: Occur in the matrix.
• Electron Transport Chain & ATP Production: Occur in the inner membrane.
• Proton Gradient Storage: Happens in the intermembrane space.

In a nutshell

Matrix Makes, Cristae Charges, ATP Synthase Spins!

• Matrix = Site of the Krebs Cycle.
• Cristae (Inner Membrane) = Holds the Electron Transport Chain.
• ATP Synthase = Uses proton gradient to generate ATP.