Lecture 24- Metabolic Microbial Diversity

Metabolic diversity

___________ is the differences in cellular processes which promote growth

cellular intermediates, several different sources

Organisms can generate ____________ and energy from ______________ depending on the metabolic capabilities.

DO NOT

These metabolic capabilities _____ fall always all along phylogenetic lines.

acquire similar metabolic capabilities

Organisms can __________ via convergent evolution or horizontal gene transfer.

Convergent evolution

The independent evolution of similar traits when adapting to a similar environment.

Photosynthesis

The conversion of light energy into cellular energy.

Autotrophy

The ability to fix carbon dioxide into an organic compound

anoxygenic (O2 absent) or oxygenic (O2 present)

Photosynthesis can be __________ or _____________.

pigments, absorb light energy

Microbes use light-sensitive ____________ which ________ in photoautotrophy. This enables photosynthesis.

Chlorophyll a and Bacteriochlorophyll a

Two main pigments used in bacteria

Chlorophyll a

oxygenic, cyanobacteria (green)

Bacteriochlorophyll a

anoxygenic, purple bacteria

Oxygenic photosynthesis

Converts light energy and water into ATP, oxygen, and reducing power

two photosystems, proton gradient

There are _________ in oxygenic photosynthesis (PS1 and PS2). The overall reaction of these photosystems results in the production of a ___________.

ATP synthase, producing ATP

The protons diffuse back into the cell through an ___________ membrane protein, _________.

Anoxygenic photosynthesis

converts light energy and hydrogen sulfide (H2S) into ATP, sulfur, and reducing power.

hydrogen sulfide replaces water, proton gradient

Key difference in anoxygenic photosynthesis is that __________________ as the electron donor when forming the ____________.

ATP synthase, producing ATP

As in oxygenic photosynthesis the protons diffuse back into the cell through an __________ membrane protein, _________.

Autotrophy

The ability to fix carbon dioxide into an organic compound such as glucose

Calvin cycle, reversal of citric acid cycle, anabolic, endergonic

Cells can use either the ________ or a ______________ to create sugars or metabolic intermediates from carbon dioxide using energy. This is an _________ and __________ reaction.

Chemotrophy

The ability to obtain energy for metabolism from chemical reactions.

Chemoorganotrophs, oxidation of organic molecules

_______________: Obtain their energy from _________________ (sugars, proteins, lipids, ect.)

Heterotrophs

Obtain carbon for biosynthesis from inorganic compounds, such as glucose. Almost all chemoorganotrophs are this.

Chemolithotrophs, oxidation of inorganic molecules

__________: Obtain their energy from _____________ (sulfur, hydrogen sulfide, ect.)

Chemolithotrophs

obtain their energy from respiration using inorganic molecules (sulfur, hydrogen sulfide, ect. )

Electron donors

__________ include hydrogen (H2), ammonia (NH3), nitrite NO2-, hydrogen sulfide (H2S), sulfur (S0) and iron (Fe2+)

terminal electron acceptor, exergonic

When utilizing molecules the ______________ must be lower on the redox table, to make the reaction _________.

nitrite, oxygen

For example, if you are using _______ as an electron donor you must use ______ as the terminal electron acceptor.

Nitrogen fixation

The process of turning nitrogen gas (N2) into ammonia (NH3) which can be used by the cell.

DNA and protein synthesis

The cell uses ammonia (NH3) to add amine groups to metabolic intermediates. This can be seen in metabolic processes such as _________________.

reducing power, energy

Nitrogen fixation consumes ___________ and cellular ___________ (endergonic).

Nitrogenase

is an enzyme complex which catalyzes the reduction of N2 and NH3. It has two components

Dinitrogenase reductase and Dinitrogenase

Two components of Nitrogenase

Dinitrogenase

Donates electrons from dinitrogenase reductase to nitrogen.

dinitrogenase reductase

Donates electrons to dinitrogenase from co-factors

agriculture, waste-water management

Ammonia is a common byproduct of ___________ and ___________ However, both ammonia and its oxidized form nitrite can be toxic to humans.

removes, toxic products

Many bacteria can oxidize ammonia (NH3) and nitrite (NO2-) into nitrate (NO3-) producing energy. This also __________ these ___________ from the environment.

Nitrification

Two-step process in which bacteria convert ammonia into fully oxidized nitrate to produce energy. Ammonia --> Nitrite --> Nitrate.

oxygen, terminal electron acceptor

_________ is used as the ____________ in nitrification as it produces the largest amount of energy.

Denitrification

The process of converting nitrite (NO2-) or nitrate (NO2-) into a gaseous form like nitrogen gas. These gases enter the air, leaving the environment.

reduction reaction, terminal electron acceptor

Denitrification is a ___________ where each intermediate of nitrogen is used as a __________ during anaerobic respiration.

multiple oxidation states, versatile

Nitrogen has _________ which can be harnessed by different bacteria, making it ________ electron acceptor.

Nitric oxide (NO), nitrous oxide (N2O), greenhouse gases

Nitrogen having multiple oxidation states is problematic for us both _______ and _________ are __________.

nitrogen gas is harmless

On the other hand, _________________ and makes up 78% of Earth's atmosphere.