Structure and Function of the Mitochondria

Overview

• The mitochondria is a double membrane organelle vital for aerobic respiration.
• Key processes: Link reaction, Krebs cycle, oxidative phosphorylation, and chemiosmosis.
• Mitochondria's unique structure enables efficient functioning.

Mitochondrial Structure

• Outer Membrane: Smooth and acts as a partially permeable barrier, allowing specific molecules like pyruvate to enter.
• Inner Membrane: Folded to form structures known as cristae.
• Circular DNA: Mitochondria contain their own naked, circular DNA.
• Ribosomes: Contains 70S ribosomes for protein synthesis.

Functionality

Protein Synthesis

• Mitochondria synthesize their own proteins.
  • Transcription: Circular DNA undergoes transcription to form mRNA.
  • Translation: mRNA is translated by 70S ribosomes to produce proteins.
• Proteins synthesized are primarily enzymes required for respiration processes.

Matrix

• Site for the link reaction and Krebs cycle.
• Provides an environment for multiple enzyme reactions critical to aerobic respiration.

Cristae

• Finger-like structures formed by the folded inner membrane.
  • Function: Increases the surface area to host more electron transport chains (ETC) and ATP synthase.
• More cristae lead to more ATP production due to increased oxidative phosphorylation and chemiosmosis.

ATP Synthase

• ATP synthase appears as 'stalked particles' in electron microscope imagery.
  • Location: Embedded in the cristae.
  • Increased number due to folding of the inner membrane.

Adaptation

• Efficiency: The more folded the mitochondria, the more efficient it is at ATP production.
• Structural adaptions optimize the mitochondria's capacity for energy production.