Lecture #19 - Biochemical Energetics

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Biology 301 Cellular and Molecular Biology Spring 2002

Lecture #19 - Biochemical energetics

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Overall Outline  Energy  ATP  Oxidation & Reduction

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Energy  Free energy  Free energy relations  Overview of cellular respiration  Overview of glycolysis  Overview of the TCA cycle  Overview of electron transport  Overview of oxidative phosphorylation

Free energy

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Free energy relations

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Overview of cellular respiration

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Overview of glycolysis ANAEROBIC   

 

  Glucose is broken down to lactate    NADH produced is oxidized by pyruvate    Net 2 ATP are produced    Reactions are relatively quick 

AEROBIC   

  Glucose is broken down to pyruvate    NADH produced is oxidized by oxygen    Net 36 or 38 ATP are produced    Reactions are relatively slow 

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Overview of the TCA cycle • Pyruvate (with 3 carbons) is broken down to 3 molecules of carbon dioxide. • “High-energy” electrons (in the form of NADH and FADH2) and ultimately ATP are produced.

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Overview of electron transport • NADH in mitochondria is oxidized to O2 by the electron transport chain — a series of electron transfer proteins embedded in the inner mitochondrial membrane.

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Overview of oxidative phosphorylation H+ is extruded by the ET chain and subsequently allowed back in by the oxidative phosphorylation apparatus (coupled to the formation of ATP). These processes take place on the inner mitochondrial membrane.

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

ATP  Phosphoanhydrides & Phosphoesters  ATP  Energy coupling  Energy coupling by phosphate transfer  The ATP cycle

Phosphoanhydrides & Phosphoesters Phosphoanhydrides are common in ATP and other “high-energy compounds.” Phosphodiesters compose the backbone of DNA and RNA.

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

ATP

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Energy coupling

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Energy coupling by phosphate transfer

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

The ATP cycle

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Oxidation & Reduction  Oxidation numbers  Combustion

Oxidation numbers

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University

Oxidation = loss of electrons Reduction = gain of electrons.

ox # Pure elements in any form

0

Oxygen (except peroxides H2O2)

-2

Hydrogen

+1

Hydrogen bonded to metal

-1

All other oxidation states are selected to make the algebraic sum equal to the formal charge

The  oxidation  number  doesn’t  necessarily  reflect  a  complete  transfer  of  electrons  but  instead describes the relative shift of electrons based on certain conventions.

Combustion

Ogan Gurel, MD Biology 301 Lecture # 19 Roosevelt University