Metabolic diversity Flashcards
What are the basic requirements for life?
Carbon source (C/CO2)
Macronutrients (N, P, S, Mg, Ca, Fe).
Trace Elements (Mn, Co, Ni, W, Zn, Se, B, Mo, Cu)
Water and an energy source
Suitable environment (physical and chemical settings)
What does the Redfield ratio represent?
The general composition of biomass as C106 N16 P1. However, more realistically shown as C106 H263 O110 N16 P1 S1-Vary significantly depending on availability of nutrients
What are the main building blocks of microbes?
Protein, Polysaccharides and derivatives, nucleic acids, and lipids. Others include dry weight. 80% of cellular mass considered water.
What factors should be taken into account in order to categorise the metabolism of an organism?
Source of energy
Electron source for biomass formation
The requirement of organic material for growth
What do organisms need energy for?
Growth, mobility, maintenance, reproduction…
What is a Phototroph and give examples
Photosynthesis-Cyanobacteria, algae, higher plants, anoxic phototrophs
What is a Chemotroph
Respiration/Fermentation=Fauna, bacteria.
Name examples of energy-rich compounds and the expected duration of the energy source
Long term: Lipids, Startch,
Short term: Adenosine Triphosphate (ATP)
Formula for Anoxygenic photosynthesis
H2S—ADP+P>ATP—->So+2e-+2H+ (no elemental O2 formed)
Formula for oxygenic photosynthesis
2H20—ADP+P>ATP–>O2+4e-+4H+ (Light used to drive endergonic reaction in order to oxidate O2 in water to produce ATP
Define Endergonic
Energy Consuming
Define Exergonic
Energy releasing
Endothermic
Heat consuming
Define Exothermic
Heat releasing
Meaning of ATP
Adenosine Triphosphate (Energy-rich phosphate esters)
Formula Aerobic reaction
C6H12O6 (glucose)+6O2–ADP+P>ATP—->6CO2+6H2O
Formula Fermentation
C6H12O6—-ADP+P>ATP—->2C3H6O3 (Lactic acid)
Electron donor is organic material, what does this make the organism?
Organotroph
Electron donor is in-organic, what does this make the organism?
Lithotroph
Lithotroph oxygenic photosynthesis equation?
2H20—ADP+P>ATP—->O2+4e-+4H+
Lithotrophic sulphide oxidisation equation?
H2S+2O2—-ADP+P>ATP—->SO4^2-+SH+
If the carbon source is organic material what does this make the organism?
Heterotroph
If the carbon source is inorganic material what does this make the organism?
Autotroph
Characteristics of lithotrophic organisms metabolism
Usually autotroph (Kelly, 1971), low energy yield due to limited supply of substrate=Low contribution to primary production of ecosystem
Energy source, electron donor, and carbon source for Photolithoautotroph
Energy Source: Light
Electron Donor: H20
Carbon Source: CO2
Energy source, electron donor, and carbon source for Chemoorganoheterotroph (Homo sapien)
Energy Source: Oxidation of electron donor
Electron Donor: Organic material
Carbon Source: Organic material
Chemolithoautotroph
Energy Source: Oxidation of electron donor
Electron Donor: NH3, FE2+, H2S, H2
Carbon Source: CO2
i.e. Nitrosomonas europaea
What are the 2 steps during degradation of organic material for chemolithoautotroph?
Step 1: Extracellular hydrolysis of polymeric compounds
Step 2: Uptake of dissolved materials
What are the 3 steps during Chemoorganotrophic bacteria degradation of organic matter?
Step 1: Extracellular hydrolysis of polymeric compounds
Step 2: Uptake of dissolved molecules
Step 3: Metabolism
Define redox reaction
Oxidation reaction i.e. when oxidation state of atoms change (electrons stripped from a compound=oxidation, electron added=Reduced)
Why do cells avoid direct reaction with O2
As it is very reactive and would cause too much heat energy as a bi-product.
