Caractéristiques des Mitochondries

Mitochondria Characteristics

• Organelles found in eukaryotic cells, absent in prokaryotic cells (e.g., red blood cells)
• Present in all cell types, except red blood cells, with numbers varying depending on cellular function (1000-3000 per cell)
• Have a double membrane
• Possess their own genome (separate from the cell's nucleus)
• Are involved in energy production (ATP)
• Exhibit diverse morphologies (shapes and sizes) in different cell types (spherical, filamentous)
• Move within cells due to interactions with the cytoskeleton

Mitochondrial Structure

• Outer membrane: Smooth and continuous, similar in composition to the cell membrane, containing 5-7nm lipid bilayer with 50-60% proteins and 40-50% lipids, enriched in porins (2-3nm diameter pores), permeable to small molecules (molecular weight < 10 kDa)
• Intermembrane space: Narrow space between the outer and inner membranes
• Inner membrane: Folded to form cristae, with a 5-6nm lipid bilayer, highly impermeable to ions, containing proteins that catalyze ATP production, rich in cardiolipin.
• Matrix: Innermost compartment of the mitochondrion, containing mitochondrial DNA (mtDNA), ribosomes (mitoribosomes), and enzymes involved in the Krebs cycle (citric acid cycle) and fatty acid oxidation.

Mitochondrial Matrix

• Contains a granular material.
• Granules contain mitochondrial ribosomes (similar to bacterial ribosomes), circular DNA (mtDNA), messenger RNA (mRNA), and transfer RNA (tRNA)
• Contains enzymes for the Krebs cycle, pyruvate oxidation, and fatty acid oxidation.

Ce quiz explore les caractéristiques et la structure des mitochondries, organites essentiels aux cellules eucaryotes. Vous apprendrez leur rôle dans la production d'énergie et leur morphologie variée. Testez vos connaissances sur ces composants cellulaires clés !