Cell Metabolism, Body Heat, and Aging Notes

Cell Metabolism Overview

• Cell metabolism refers to the biochemical processes that occur within cells, involving the conversion of nutrients into energy.

Mitochondrion Structure

• Mitochondria are often referred to as the powerhouses of the cell.
• Components of Mitochondria:
  • Outer Mitochondrial Membrane (OMM): A permeable membrane that houses various proteins and receptors.
  • Inner Mitochondrial Membrane (IMM): Contains the Electron Transport Chain (ETC) and is less permeable.
  • Intermembrane Space: The space between the OMM and IMM where protons accumulate during the ETC.
  • Matrix: The innermost compartment containing enzymes for the Krebs cycle and mitochondrial DNA.

Electron Transport Chain (ETC)

• The ETC is a series of complexes (I-IV) in the IMM that facilitate electron transfer and proton pumping into the intermembrane space, creating a proton gradient.
• Key Molecules:
  • NADH and FADH2 donate electrons to the chain.
  • Oxygen acts as the final electron acceptor, producing water.
  • ATP Synthase uses the proton gradient to generate ATP from ADP and inorganic phosphate (Pi).

Body Heat Generation (Endothermy)

• Uncoupling Proteins (UCP): Special proteins that facilitate the 'short-circuit' of the voltage across the IMM, resulting in heat generation instead of ATP production.
• This process is crucial for maintaining body temperature in endothermic organisms.

Aging and Cellular Damage

• Aging can be influenced by reactive oxygen species (ROS), which are byproducts of normal cellular metabolism.
• Oxygen and Aging:
  • Oxygen is essential for aerobic metabolism but also can be damaging; it is described as "impatient and greedy" for electrons.
  • ROS can damage DNA and proteins over time, contributing to cellular aging and dysfunction.
  • Cited Research: Balaban et al. (2005) discuss the impact of reactive oxygen species on cellular aging.

Regulation of Aging by Ion Channels and Transporters

• Study Reference: Venkatachalam K. (2022) discusses the role of ion channels and transporters in aging and longevity, showcasing the complexity of metabolic regulation in aging processes.