Pg:- 33 #cell #biology #partofcell
Mitochondria are often referred to as the "powerhouses" of the cell
Structure of Mitochondria:
Mitochondria have a unique double-membrane structure:
Outer Membrane: This membrane is relatively permeable to ions and small molecules, allowing for the exchange of substances between the mitochondrion and the cytoplasm.
Inner Membrane: This membrane is highly selective and contains many folds called cristae, which increase the surface area for energy production. The inner membrane houses the proteins and enzymes involved in the electron transport chain and ATP synthesis.
Matrix: The innermost compartment, filled with enzymes, mitochondrial DNA (mtDNA), ribosomes, and various molecules involved in metabolic processes.
Primary Functions of Mitochondria:
ATP Production: The most well-known function of mitochondria is the production of adenosine triphosphate (ATP), the cell's primary energy currency. This process occurs through oxidative phosphorylation, where electrons are transferred through the electron transport chain, ultimately leading to the generation of ATP from adenosine diphosphate (ADP) and inorganic phosphate (Pi).
Regulation of Cellular Metabolism: Mitochondria are central to various metabolic pathways, including the citric acid cycle (Krebs cycle) and fatty acid oxidation. These pathways break down carbohydrates, fats, and proteins, providing the necessary substrates for ATP production.
Calcium Homeostasis: Mitochondria help regulate intracellular calcium levels, which is crucial for numerous cellular functions, including muscle contraction, signal transduction, and cell death.
Apoptosis (Programmed Cell Death): Mitochondria play a key role in apoptosis by releasing cytochrome c, a component of the electron transport chain, into the cytoplasm. This release triggers a cascade of events that lead to cell death, which is essential for eliminating damaged or unwanted cells.
Reactive Oxygen Species (ROS) Production and Detoxification: During ATP production, mitochondria generate reactive oxygen species as byproducts. While ROS are important signaling molecules, excessive ROS can damage cellular components, leading to oxidative stress. Mitochondria have mechanisms to detoxify ROS, maintaining cellular health.
Steroid Synthesis: Mitochondria are involved in the synthesis of steroid hormones, particularly in tissues like the adrenal glands. These hormones are vital for regulating metabolism, immune response, and other physiological functions.
1.What are cristae, and what is their function?
2.Where is mitochondrial DNA located within the mitochondrion?
3.How do mitochondria contribute to cellular respiration?
4. What is the role of the inner and outer membranes of mitochondria?
5.How do mitochondria replicate within a cell?
6.What types of cells contain the most mitochondria and why?