Microbial Energetics Flashcards by KAYLIE WILLIAMS

Microbial diversity equals

metabolic diversity

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What are photolithoautotrophs?

Get energy from light

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What are chemoheteroorganotrophs?

Get energy from oxidation and organic compounds

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What are chemolithoautotrophs?

Oxidize inorganic chemicals for energy

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What is the definition of metabolism?

The sum total of all rxns which occur in a cell. Consists of two types of processes, catabolism and anabolism

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What is the definition of catabolism?

The use of chemical reactions to generate energy and reducing power (electrons) that drive cellular functions. These reactions can involve the breakdown of complex molecules into smaller ones, but these are many exceptions where this doesn’t occur

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What is the definition of anabolism?

Synthesis of needed cellular structures from simpler compounds, this requires energy often from reducing power.

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What is the requirement for growth?

Energy

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Energy is able to do _____.

work

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In the gibbs free energy equation what do the following mean…
a. H
b. S
c. G

a. total energy of a rxn
b. amount of energy that is lost to disordering (entropy) the system and is not available for work
c. the amount of free energy available to do work

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An increase in S results in….

randomization of the system giving a negative delta G (favorable)

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A decrease in S results in…

Ordering of a system and a positive delta G

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Breaking things down often ______ energy?

Releases

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Building things up ________ energy?

Costs

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If there is a high substrate concentration what will happen to the rate of rxn?

Increase and we see a forward rxn

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If there is a low concentration of products what will happen to the rate of the rxn?

Increase the rate of the forward reaction

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All reactions require _____ to occur?

activation energy

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What is the reaction intermediate?

Two substrates that are destabilized and brought together

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What is the purpose of enzymes?

Bring substates together (increase local concentration)
Bend substrates to resemble the reaction intermediate

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What is chemical energy?

Potential energy of electrons

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What is an electron donor?

something that loses electrons and gets oxidized

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What is an electron acceptor?

something that gains electrons and gets reduced

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How is energy released?

Energy is released as electrons move to place of lower potential energy

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How is electron transfer linked to ATP synthesis?

Electron transfer is associated with the release of potential energy, captured by ATP, an energy carrier

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Chemicals ____ in their tendency to donate or accept electrons?

VARY....Can be measured or expressed in half rxns

Oxidized form of rxns are always on _____ while reduced forms always on _____.

Left Right

A lower MeV corresponds to.....

good electron donors

A higher MeV corresponds to....

good electron acceptors

What kind of reduction potential does a donor have?

Negative reduction potential

What kind of reduction potential does an acceptor have?

Positive reduction potential

When calculating potential drop a positive drop in potential corresponds

favorable rxn

Electron transfer is not often ____.

direct

What protein electron carriers shuttle electrons?

- Cytochromes - Flavoproteins

What protein small molecule electron carriers shuttle electrons?

- NADH - FADH - Quinones

What do energy storage systems do?

capture energy released from chemical reactions

Released free energy can be conserved by the cell as what?

Chemical bond or ion motive force

What is an example of chemical energy storage?

ATP binding - conformational change - ATP hydrolyzed to go back to original form

ATP.....

Stores chemical energy

What are other ways to store chemical energy (molecules)?

- PEP - CoA - Acetyl-P

Chemical energy can be stored as what?

Phosphate bonds

Free energy can be _______.

Manipulated

Enzymes ______ reactions.

bind

What is fermentation?

Reactions that occur in the absence of oxygen. both donor and acceptor are both organic chemicals

What is Substrate level phosphorylation and what is it used for?

Energy generation! Synthesis of ATP from ADP is coupled with the breakdown of high energy organic substances

What are systems used for generating energy?

- substrate level phosphorylation - membrane system phosphorylation

What are membrane systems of phosphorylation?

- oxidative or electron transport level phosphorylation - anaerobic respiration - photophosphorylation

What is a glycolytic pathway?

Breaks down glucose down to smaller molecules

The Embden-Meyerhoff Pathway is present in?

Many bacteria and Archaea

What organisms use Entner Douderoff Pathway?

Mostly strictly aerobic bacteria

What is hexose splitting?

1. Molecule activated then split 2. The reaction pulled toward GAP 3. Phosphates added and then removed as energy

What does the Entner-Duodoroff Pathway yield?

2 reducing equivalents NAD NADH

What are the end products of glycolysis?

Pyruvate NADH

What is pyruvate used for?

Carbon source

What is NADH used for?

Biosynthesis reactions

What is the rest of NADH used for after biosynthesis reactions?

Fermentation you have to get rid of excess NADH

What is the definition of fermentation?

Energy yielding process wherby organic molecules serve as both electron donors and acceptors

In fermentation what is pyruvate used for?

Important intermediate

How is energy derived for fermentation?

Substrate-level phosphorylation

What is the energy yield for fermentation?

Generally really low

Is oxygen involved for fermentation?

What are typical substrates for fermentation?

1. Sugar 2. Amino Acids

What are typical products that depend on substrates?

1. organic acids - lactic and acetic acid 2. alcohols - ethanol, methanol, butanol 3. Gases - hydrogen gas and carbon dioxide

What are the three important fermentations we discussed in class?

1. Alcoholic fermentation by Saccharmoyces yeast 2. Homofermentation - lactic acid only product 3. Propionic fermentation of Propionibacterium

Alcoholic fermentation is a ____ step reaction?

What are the two steps of alcoholic fermentation?

1. Decarboxylation to form acetylaldehyde 2. Reduction to ethanol using NADH

How many breweries are in the US?

>8000 breweries

What are brewing ingredients for beer?

1. Malted Barley 2. Water 3. Hops 4. Yeast

What are the steps of the brewing process?

1. Malting germinate barely 2. mashing - extract starch - convert sugars 3. Boil wort, add hops 4. Fermentation glycolytic pathway

What is the process of ethanol formation?

Take pyruvate and aetyladehyde and it is combined and reduced to ethanol.

Acetylaldehyde is a ______ taste?

Green apple tast

In ethanol formation if there is a back up of acetylaldehyde what happens?

Green apple taste

what are the steps of beer production?

1. Malting 2. Mashing 3. boiling 4. Fermentation 5. bottling and distribution

For homofermentation how many ATP are added per glycolysis?

For homofermentation how many ATP are generated per glucose?

4 ATP 2 NET ATP

What are different lactic acid bacteria?

1. Streptococcus 2. Lactococcus 3. Some lactobacillus

What is heterofermentation?

Different fermentation of glucose

How many ATP are yielded from heterofermentation?

1 ATP

What are the products of heterofermentation?

1. Lactate 2. CO2 3. Ethanol

What are different heterofermentation bacteria?

- Leucocnostoc - Other lactobacillus

What are the steps in cheese making?

1. Collect and pasturize raw milk 2. Add starter culture 3. Add renet and form milk curds 4. Curd concentration 5. Press curds into molds and salt 6. Added second starter culture if needed 7. Age for weeks 8. Remove the cheese from molds and package for sale

What is kimchi?

Vegetable fermentation (Natural fermentation)

How is kimchi fermented?

Fermented by cabbage by lactic acid bacteria and coliforms

What gives kimchi its natural flavor and texture?

lactic acid bacteria

What is the fermentation progression of kimchi? (KNOW CHART ON LEC SLIDES)

1st Coliforms - non pathogenic klebsiella and enterobacter - ferments sugar to acidic products and lowers pH to 5 2nd Lauconostoc - Lactic acid bacteria - Heterofermentative - gas produced - stops fermentating at about pH 4.5 3rd Lactobacillus - Homofermentative - produces more lactic acid - lowers pH to near 4.0

chocolate undergoes what kind of fermentation?

Natural fermentation

What are the psycho active products in chocolate?

- Anandamide (A) - blissful feeling - Theobromine - Stimulant (B)

Explain chocolates fermentation process?

- Cacao pods have seeds (beans) covered in mucilage (carbohydrate) - Pods are broken open and natural microbes ferment mucilage - Complex succession of microbes make products

Microbial Energetics Flashcards

(87 cards)