Microbial Metabolism Flashcards
What is catabolism?
Breakdown organic molecules
Degradation or hydrolysis of molecules
Carbon skeletons, reducing power (e-) and energy (ATP) are PRODUCED
Catabolic pathways are exorgenic (releases energy)
What is metabolism and what 2 components can it be divided into?
Sum of all complex biochemical reactions within an organism
Catabolism - breakdown of nutrient molecules and release of energy stored in ATP molecules
Anabolism - synthesis of macromolecules using ATP as energy
What is anabolism?
Synthesis of new material for the cell
Carbon skeletons, reducing power and energy are USED
protein synthesis, peptidoglycan synthesis, lipid synthesis and nucleic acid synthesis
Anabolic pathways are endergonic (energy using)
What is an oxidative reaction and what is a reduction reaction?
OIL RIG
Oxidation Is Loss of electrons
Reduction Is Gain of electrons
Describe oxidative - reduction reactions
Involves transfer of electrons
Electrons carry high amounts of potential energy
Transfer is energy releasing action that drives cellular processes
Occurs simultaneously - electron lost is one gained by another molecule
Molecule accepts electron (or atom) - term is reduced
Molecule losing electron (or atom) - term is oxidised
Name 2 oxidised and reduced molecules
Oxidised - NAD+ and FAD
Reduced - NADH and FADH2
How does the first law of thermodynamics relate to oxidative reduction reactions?
Energy is never created or destroyed it only changes form
Chemical energy is a form of potential energy (PE) - stored in the binds of a molecule
The more highly reduced a molecule the more PE
O-R reactions result in a transfer of energy
Removal/addition of phosphate group results in transfer of energy in a cell
ADP->ATP = increase in PE within the bond
ATP->ADP = release of PE
What roles do enzymes play in catabolism?
Enzymes catabolise nutrients into precursor molecules (amino acids, monosaccharides, fatty acids) Form macromolecules (proteins, polysaccharides, lipids) Cell grows as it assembles large molecules into structural components (proteins, phospholipids, peptidoglycan)
Name the 2 classifications of Microorganisms based on energy source and the 2 based on Carbon source
Phototrophs - light primary source
Chemotrophs - O/R reactions of organic compounds primary source
Autotrophs - CO2 as sole C source
Heterotrophs - organic C sources
What are the three classifications of chemoheterotrophs?
Parasites - derived from living host
Decomposers - in soil
Spoilage organisms in food
How have enzyme activities been exploited by humans?
Alcohol production
Cheese production
Yoghurt production
Sewage treatment
Features of aerobic respiration
Glycolysis, tricarboxcylic acid (TCA) cycle and respiratory chain
Glucose broken down to CO2, H2O and energy
Relies on free oxygen as final acceptor of electrons
Principal energy yielding process in aerobic heterotrophs
Large amount of ATP - 38 molecules for 1 glucose
Characteristic of many bacteria, fungi and protozoa
Features of anaerobic respiration
Can use the same three pathways as aerobic but does not use molecular oxygen as final electron acceptor instead - Sulphate, Nitrate, Sulphur
Features of fermentation
Facultative and aero tolerant anaerobes May only use glycolysis scheme Incompletely oxidises glucose - ferments Oxygen is not terminal acceptor - uses organic compounds Small amount of ATP is produced
What 2 reactions are used by the cell to synthesise ATP?
Substrate cell phosphorylation - transfer of phosphate from phosphorylated organic nutrient to ADP to form ATP
Oxidative phosphorylation - phosphorylated ADP using inorganic phosphate and energy released I. Catabolic breakdown of nutrients via cellular respiration
