Metabolisme

Susila Sastri

Metabolisme

• Definisi: rangkaian reaksi-reaksi kimia dalam sel yang terjadi secara continue dan saling berhubungan satu dengan yang lain– Anabolisme – Katabolisme– Ampibolic

Overview Metabolisme

Metabolisme

• Bahan bakar tubuh : carbohydrates, fats, dan proteins

( makromolekul)

• Energi : oxidasi :CO2 and H2O.

• Cadangan dalam tubuh : triacylglycerol (fat), glycogen (carbohydrate)

• Penurunan atau penambahan BB normal: Energi dipakai – Energi tersedia

• insulin dan glucagon; regulator pemakaian dan penyimpanan bahan cadangan

• Karbohidrat utama dalam darah : glukosa : regulator insulin dan glukagon dalam darah

Puasa

• Puasa : hypoglisemia , memicu pamkreas agar glukagon disekresi

• Glucagon: cadangan carbohydrat membebaskan glucose ke sirkulasi ( brain)

• Puasa lebih 3 : ketone bodies (derived from fat) as an alternative fuel supply for the brain.

Anabolisme• Biosintesis senyawa biomolekul (glikogen,

protein, trigliserida)• Butuh Energi (endergonic). • ATP: ADP + Pi (ATP-ADP cycle)• Misal

– Glikogenesis– Glukoneogenesis– Biosintesa asam lemak– Biosintesa protein

Katabolisme

• Pemecahan molekul besar : molekul kecil (glukosa, asetil KoA, Asam amino) CO2 dan Energi (ATP)

– CO2 : sirkulasi– ATP : dibebaskan setelah elektron

ditransfer ke O2

• Mis: – Glikolisis– Glikogenolisis– Oksidasi asam lemak

Amphibolic

• Anabolisme dan Katabolisme: terjadi dalam satu proses metabolism

• Siklus Kreb– Biosintesis heme, glukosa, asam lemak– Katabolisme: sitrat, ketoglutarat

Energi

• Oxidation of fuels to generate ATP is called respiration • Electrons lost from the fuels during oxidative reactions :

transferred to O2 by a series of proteins in the electron transport chain

• Energy of electron transfer : used to convert ADP and Pi to ATP by a process known as oxidative phosphorylation

• Satuan Energi :– Calori– kilocalorie – kilojoules (kJ)

The ATP-ADP cycle

Generation of ATP

approximate order in which the processes occur. TG = triacylglycerols; FA = fatty acid; AA = amino acid; RBC = red blood cell; VLDL = very low density lipoprotein; I= insulin; % = stimulated by.

Metabolisme KH, Fat AA

TAG = triacylglycerol

Overview Metabolisme KH

Overview of fatty acid metabolism

Overview of amino acid metabolism

Transport and fate of major carbohydrate and amino acid substrates and metabolites

Transport and fate of major lipid substrates and metabolites

FFA, free fatty acids; LPL, lipoprotein lipase; MG, monoacylglycerol; TG, triacylglycerol; VLDL, very low density lipoprotein.

Intracellular location and overview of major metabolic pathways