Major Metabolic Pathway Dr. Saleha Shamsudin

Introduction to metabolism and bioenergetics. Glucose metabolism: Glycolysis and TCA cycle, Respiration. Metabolism of nitrogenous compounds and hydrocarbons. Overview of biosynthesis for small and macromolecules, anaerobic and autotrophic metabolism.

Major challenges in bioprocess development: To select an organism that can efficiently make a given product Before 1980 only naturally occurring organisms were available (wild type organism). With the advent of genetic engineering, it is possible to remove or add genes to an organism to alter its metabolic functions in a predetermined manner (metabolic engineering) It is important to understand the metabolic pathways in natural organisms either to use them directly or to metabolically engineer them to make a desired, novel product.

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M : a complete set of chemical reactions that occur in living cells, allowing cells to grow and reproduce, maintain their structures, and respond to their environments. Metabolic Pathways

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Even the same species may produce different product when grown under different nutritional and environmental regulation. Example: Saccharomyces cerevisiae (baker’s yeast) produces ethanol when grown under anaerobic conditions. However, the major product is yeast cells when growth conditions are aerobic. More over, even under aerobic conditions at high glucose concentrations, some ethanol production is observed. Which indicates metabolic regulation not only by oxygen, but also by glucose. This effect is known as the crabtree effect. Therefore, control of metabolism is important in bioprocess Characteristics of metabolism: 1. Varies from organisms to organism 2. Effected by environmental condition.

glucose to glycogen ~produce energy to the cell ~requires energy

-Living cell require energy for biosynthesis, transport of nutrient, motility and maintainance. -Energy is obtained from the catabolism of carbon compounds (carbohydrate) -Carbohydrates are synthesized from CO 2 and H 2 O in the present of light by photosynthesis.

the part of biochemistry concerned with the energy involved in making and breaking of chemical bonds in the molecules found in biological organisms.biochemistrymoleculesorganisms

Bioenergetics Sunlight Photosynthesis by autotrophs : CO 2 + H 2 O → carbohydrates Anabolism requiring energy Catabolism generating energy, e.g ATP Autotrophs or heterotrophs

Autotrophs and Heterotrophs Organisms are divided into autotrophs and heterotrophs according to their energy pathways. Autotrophs are those organisms that are able to make energy-containing organic molecules from inorganic raw material by using basic energy sources such as sunlight. Plants are the prime example of autotrophs, using photosynthesis. All other organisms must make use of food that comes from other organisms in the form of fats, carbohydrates and proteins. These organisms which feed on others are called heterotrophs.photosynthesis

Three major categories of metabolic reactions: (I) degradation of nutrients (II) Biosynthesis of small molecules (III) Biosynthesis of large molecules

- Energy is mainly stored or transferred by adenosine triphosphate (ATP) ~ (contains high-energy phosphate bonds) Other energy carrying compounds include GTP, UTP and CTP.

Glucose Catabolism Glucose Aerobic metabolism Anaerobic metabolism Tricarboxylic acid (TCA) or (Krebs) or (Citric acid cycle) (pyruvate is converted to CO2 +NADH) Oxidative phosphorylation Glycolysis or Embden-Meyerhof-Parnas (EMP) Fermentation: ethanol, acetic acid, lactate.