Metabolism

Catabolism

Energy (ATP)Small molecules (precursors)

Anabolism

Large molecules

Biosynthesis of Macromolecules

Anabolism- use energy (ATP) from catabolism

- use carbon from sugars, lipids, proteins, or any other carbon source (xenobiotics) to build cellular components

Key Intermediates

• Located in the glycolytic pathway– Ex. Glucose-6-phosphate, pyruvic acid, etc.

• Located in the TCA cycle– Ex. Oxaloacetic acid, ketoglutaric acid

Central Metabolic pathway

• Catabolism and anabolism are interconnected due to amphibolic pathways

Lipid Biosynthesis• Fatty acid biosynthesis- Acetyl-CoA---

>fatty acid (cell structure)

• Poly-ß-hydroxybutyric acid- Acetyl-CoA---> Poly. (storage)

• Phospholipid- Glycolytic intermediate---> lipid ( membrane)

• Sterols- eukaryotic cell membrane

Amino Acid Biosynthesis• Amination – addition of an amine group (N

containing) to a critical intermediate

• Transamination - new amino acids are made from the amine group from old amino acids

Nucleotide Biosynthesis• N molecule (amino acid), five carbon

sugar, phosphate combine =>nucleotides (DNA, RNA)

• Five carbon sugar– Pryrimidines- cytosine, thymine– Purines- adenine, guanine

Polysaccharide Biosynthesis

• Peptidoglycan- Glycolytic intermediates, nucleotides --->PEG

• Lipopolysaccharide- Glycolytic intermediates, other sugars ---> LPS, teichoic acid, mycolic acid, glycogen, etc.

Photosynthetic microbes• Carbon dioxide fixation

– Inorganic CO2 is incorporated into the cellular structure (Calvin cycle)

Metabolic diversity

• Different sources of carbon and energy exist for various microbes, plants, and animals.

Metabolic diversity

Four main groups of microbes

1.) chemoheterotrophs

2.) chemoautotrophs

3.) photoautotrophs

4.) photoheterophs

Chemoheterotrophs

• Many medically important microbes are in this category (E. coli, B. anthrasis, etc.)

• Carbon source = organic molecules (carbohydrates, proteins, lipids, xenobiotics)

• Energy source=organic molecules (carbohydrates, proteins, lipids, xenobiotics)

Chemoautotroph

• Many soil microbes

• Source of carbon = inorganic molecule (ex. CO2)

• Source of energy = electrons from inorganic compounds (ex. S, H2S, NO2)

Photoautotroph

• Photosynthesis (green sulfur bacteria, etc.)

• Source of carbon = CO2

• Source of energy = light

Photoheterotroph

• photosynthesis (green nonsulfur bacteria, etc.)

• Source of carbon = organic molecule ( ex. Fatty acids, alcohol, etc.)

• Source of energy = light

Summary of Anabolism

• Use ATP (energy) from catabolism for biosynthesis

• Build small molecules into larger molecules or cell structures (ex. Glucose, amino acids, fatty acids=>lipid, PG)

• Diversity of metabolic systems (chemoheterotrophs, etc.)

• Cell division (binary fission)=anabolism

• Catabolism and anabolism are integrated

• (amphibolic pathways)