Metabolism

Metabolism

Dr.kareema Amine Al-Khafaji Assistant professor in microbiology, and dermatologist Babylon University , College of Medicine , Department of Microbiology.

Metabolism – sum of all chemical processes
– Anabolism – reactions that require energy to synthesis complex molecules from simpler one.
• Essential for growth, reproduction & repair
– Catabolism – reactions that release energy by breaking
complex molecules into simpler ones
• Essential for providing energy for life processes; movement, transport & synthesis of complex molecules

Energy metabolism
• Catabolic reactions involve electron transfer – allows
energy to be captured in high energy compounds such
as ATP
• Electron transport related directly to oxidation & reduction
- enzymes are specific for a given substrate
- energy for reactions is stored as ATP (adenosine triphosphate)
- when a bond is broken energy released is used to run other reactions
- ATP is generated in some reactions and used to drive others
– Oxidation = loss or removal of electrons
• Many substances combine with O and transfer electrons to O2; O2 need not be present if there is another electron acceptor available
– Reduction = gain of electrons
• Energy is released and another substance must gain the electrons
or be reduced at the same time
• Eg 2 H2 + O2 ??2H2O : hydrogen is electron donor
(reducing agent) and oxygen in electron acceptor (oxidising agent)
• As oxidation & reduction must occur simultaneously the reactions in which they occur are called redox reactions
Respiration – 3 phases (Net production of ~38 ATP molecules)
1. Glycolysis – breakdown of glucose – ATP produced
2. Krebs Cycle – further breakdown, more ATP produced
3. Electron Transport Chain – electrons transported through a series of carriers, ATP produced