Mitochondria are often referred to as the "powerhouses" of the cell because their main function is to produce energy. They are double-membraned organelles found in the cells of most eukaryotic organisms (animals, plants, fungi, and protists). Here's a breakdown of their structure and key functions:

🔬 Structure of Mitochondria:

Outer Membrane – Smooth and permeable to small molecules.

Inner Membrane – Folded into cristae, increasing surface area for energy production.

Intermembrane Space – Between the outer and inner membranes.

Matrix – The innermost compartment containing enzymes, mitochondrial DNA, and ribosomes.

⚙️ Functions of Mitochondria:

ATP Production (Cellular Respiration):

• Primary function.
• Glucose and oxygen are used to produce ATP (adenosine triphosphate) through a process called aerobic respiration.
• Main steps: Glycolysis (in cytoplasm) → Krebs cycle → Electron transport chain (in inner membrane).

Regulation of Cellular Metabolism:

Mitochondria help control metabolic activity, determining when and how energy is produced and used.

Calcium Storage and Signaling:

Help regulate calcium levels, which are vital for muscle contraction, hormone signaling, and more.

Apoptosis (Programmed Cell Death):

Mitochondria release proteins that activate cell death pathways—crucial for removing damaged or unnecessary cells.

Heat Production (Thermogenesis):

In brown fat cells, mitochondria produce heat instead of ATP, especially in newborns and hibernating animals.

Synthesis of Certain Hormones and Molecules:

They assist in the synthesis of steroid hormones and some parts of heme (used in hemoglobin).

Contain Their Own DNA (mtDNA):

Unlike most organelles, mitochondria have their own circular DNA, inherited maternally.