Microbio Exam 3

Aerobic Respiration

Catabolic reaction that collects the most energy (38 ATP per Glucose)

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1. Glycolysis (8 ATP)


1. Glucose + 2 NAD+ → 2 Pyruvate + 2 ATP + 2 NADH
2. 2 NADH + Oxidative Phosphorylation → 6 ATP
2. CAC (15 ATP x2)


1. Pyruvate + 4 NAD+ + GDP + FAD → 3 CO2 + 4 NADH + FADH2 + GTP
2. 4 NADH + Oxidative Phosphorylation → 12 ATP
3. 1 FADH2 + Oxidative Phosphorylation → 2 ATP

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Involves:

* Glycolysis
* The Krebs Cycle
* The ETS

Glycolysis of Pyruvic Acid

Preparation for the Krebs Cycle in Aerobic Respiration

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Pyruvic acid (3C) → acetyl CoA (2C) + CO2

1 NADH formed per pyruvate conversion

Krebs Cycle

An oxidative metabolic pathway that starts with Acetyl Co A and produces CO2 and NADH

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Repetitive cycle involving 9 carbon compounds used in Aerobic Respiration

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Primed w/ Glycolysis of Pyruvic Acid to create Acetyl CoA (2C)

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1. Acetyl group (2C) + Oxaloacetic acid (4C) → Citric acid (6C)
2. Citric acid (6C) → 7 steps → Oxaloacetic acid (4C)

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Generates many compounds available for Biosynthetic purposes:


1. Alpha Ketoglutarate
2. Oxaloacetate
3. Succinyl-CoA
4. Acetyl-CoA

NADH + 1 FADH2 formed per acetyl group

1 GTP formed per acetyl group

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Releases CO2

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Fumarate → Succinate w/in this cycle, which is important to some bacteria:

* Escherichia coli
* Proteus sp.
* Enterococcus sp.

Glyoxylate Cycle

Involved in Aerobic Respiration

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Catabolism of C2-C3 organic acids typically involves the Oxaloacetate produced through this cycle

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Variation of the Krebs Cycle

Electron Transport System (ETS)

Involved in Aerobic Respiration and located in Cell Membranes

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Utilizes NADH and FADH2 formed in Glycolysis of Pyruvic Acid and Krebs Cycle

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e- released to this system and provides energy for active transport of H+ from matrix to outside of membrane to form a membrane potential

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The process by which NADH transfers electrons along a chain of acceptors to oxygen

Chemiosmotic ATP Synthesis

Involved in Aerobic Respiration

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e- released from ETS provides energy for active transport of H+ from matrix to outside of membrane to form a membrane potential

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Movement of H+ down concentration gradient provides energy to make ATP from ADP and Pi

Oxygen

The final acceptor for hydrogen ions in aerobic respiration

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Terminal e- acceptor, important role in ETS and ATP synthesis in Aerobic Respiration

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Superoxide dismutase and catalase work together to convert superoxide into this

Anaerobic Respiration

The use of e- acceptors other than oxygen

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Collects less energy compared to Aerobic Respiration

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Completely dependent on ETS, generation of Proton Motive Force, and ATPase activity

Facultative Anaerobes

Microbes that use oxygen when available, but can continue to grow without oxygen

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NO3- → N2O → N2

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Ex.

* Pseudomonas sp.
* Bacillus sp.
* Moraxella sp.

Pseudomonas sp.

Example of Facultative Anaerobe

Bacillus sp.

Example of Facultative Anaerobe

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Subtilis species uses the enzyme Amylase to convert Starch to Glucose

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Species Stearothermophilus is an example of a Thermophile that grows best at 60 degrees C

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Controlled via Triphenyl Methane Dyes

Moraxella sp.

Example of Facultative Anaerobe

Anaerobic

Microbes that grow without the presence of oxygen

Oxygen is toxic to them

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Ex.

* Desulfovibrio sp.

Desulfovibrio sp.

Example of an Anaerobe

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An organism that can convert H2SO4 to H2S

Escherichia coli

Bacteria that grows using the Fumarate → Succinate portion of the Krebs Cycle

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Uses the Beta Galactosidase enzyme to convert Lactose into Glucose and Galactose

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Example of a Mesophile, growing best at 39 degrees C

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Facultative Anaerobe

Proteus sp.

Bacteria that grows using the Fumarate → Succinate portion of the Krebs Cycle

Enterococcus sp.

Bacteria that grows using the Fumarate → Succinate portion of the Krebs Cycle

Methanogenic bacteria

Anaerobic bacteria found in intestinal tracts, sewage plants, and ruminants

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Grow by converting CO2 to CH4

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Ex.

* Methanobacter sp.
* Methanococcus sp.

Methanobacter sp.

Example of Methanogenic Bacteria

Methanococcus sp.

Example of Methanogenic Bacteria

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Obligate Anaerobe

Acidophiles

Like low pH

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Anaerobic bacteria of this group grow by converting Fe3+ to Fe 2+

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Ex.

* Thiobacillus feroxidans
* Fungi
* Yeast

Thiobacillus Feroxidans

Example of Acidophilic Bacteria

Chemolithotrophy

Catabolism type that uses inorganic chems as e- donors

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Typically Aerobic

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1. Oxidation of inorganic e- donor
2. ETS/Proton Motive Force
3. Autotrophy, using CO2 as C source

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e- donors typically include:


1. H2S (Hydrogen Sulfide)
2. H2 (Hydrogen Gas)
3. Fe2+ (Ferrous Iron)
4. NH3 (Ammonia)

Catabolism

Rxns that break down big chems into small chems to release energy

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Ex.


1. Glycolysis
2. Fermentations
3. Aerobic Respiration
4. Anaerobic Respiration
5. Chemolithotrophy
6. Phototrophy

Phototrophy

Catabolism that uses light as energy source

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3 types:


1. Photophosphorylation
2. Photoautotrophs
3. Photoheterotrophs

Photophosphorylation

A type of Phototropic Catabolism

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Light-mediated ATP synthesis

Photoautotrophy

A type of Phototrophic Catabolism

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uses ATP for assimilation of CO2 for biosynthesis

Photoheterotrophy

A type of Phototrophic Catabolism

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uses ATP for assimilation of organic carbon for biosynthesis

Cellulase

Enzyme that converts the Carbohydrate Cellulose substrate into the Glucose monomer

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Used by:


1. Clostridium sp.
2. Actinomyces sp.

Clostridium sp.

Bacteria that uses Cellulase to convert Cellulose to Glucose

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Perfringens species is the etiolytic agent for Gas Gangrene due to the enzyme Phospholipase, converting Phospholipids into Phosphorylcholine and Fatty Acids

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Sporogenes species is a Obligate Anaerobe

Amylase

Enzyme that converts the Carbohydrate Starch substrate into the Glucose monomer

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Used by:


1. Bacillus Subtilis

Bacillus Subtilis

Aerobe

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1. Uses the Amylase enzyme to convert Starch into Glucose
2. Uses the Lipase enzyme to convert Triglycerides into Glycerol and Fatty Acids

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Can be tested for using:


1. Starch Agar
2. Spirit Blue Agar

Beta Galactosidase

Enzyme that converts the Carbohydrate Lactose substrate into the Glucose and Galactose monomers

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Used by:


1. Escherichia Coli

Starch Agar

Media that tests for the production of the Amylase enzyme

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Picture shows a positive result, as seen by the degradation

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Microbes that produce a positive effect:


1. Bacillus Subtilis

Lipase

Enzyme that converts the Lipid Triglyceride substrate into the Glycerol and Fatty Acid monomers

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Used by:


1. Bacillus Subtilis
2. Staphylococcus Aureus

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Tested for using the Spirit Blue Agar media

Spirit Blue Agar

Differential Media used to test for the production of the Lipase enzyme

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Picture shows a positive result, as seen by the degradation of fat

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Microbes that produce a positive effect:


1. Bacillus Subtilis
2. Staphylococcus Aureus

Staphylococcus Aureus

Bacteria that produces the enzyme Lipase to convert Triglycerides into Glycerol and Fatty Acids

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Can be tested for using:


1. Spirit Blue Agar

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Example of a Halotolerant

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Facultative Anaerobe

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Controlled via Triphenyl Methane Dyes and Acridine Dyes

Phospholipase

Enzyme that converts the Lipid Phospholipid substrates into Phosphorylcholine and Fatty Acids

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Responsible for the development of Gas Gangrene due to its Hemolytic nature

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Used by:


1. Clostridium Perfringens

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Tested for using the Egg Yolk Agar media

Clostridium Perfringens

Microbe that uses the enzyme Phospholipase to convert Phospholipids into Phosphorylcholine and Fatty Acids

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Etiologic agent for Gas Gangrene due to Phospholipase

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Also uses the Cellulase enzyme to convert Cellulose into Glucose

Egg Yolk Agar

Media used to test for the production of the enzyme Phospholipase

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Microbes that produce a positive effect:


1. Egg Yolk Agar

Beta Oxidation

Metabolizes fatty acids released by lipases and phospholipases

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Converts:


1. Co A into Acetyl Co A
2. FAD into FADH
3. NAD into NADH

Protease

Enzyme that converts Protein substrates into Amino Acid monomers

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Used by:


1. Serratia Marcescens

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Tested for using Skim Milk Agar

Serratia Marcescens

Microbe that uses the Protease enzyme to convert Proteins into Amino Acids

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Can be tested for using:


1. Skim Milk Agar

Skim Milk Agar

Media used to test for the production of Protease, converting Protein into Amino Acids

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Microbes that produce a positive effect:


1. Serratia Marcescens

Glutamate Dehydrogenase

Enzyme that removes or adds ammonia during Amino Acid Metabolism and Biosynthesis of Amino Acids

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Using this enzyme:

Alpha Ketoglutarate + NH3 + NADH → Glutamate (NH2)

Glutamine Synthetase

Enzyme that adds ammonia during Amino Acid Metabolism and Biosynthesis of Amino Acids

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Using this enzyme:

Glutamate (NH2) + NH3 + ATP → Glutamine (2 NH2)

Trasaminase

Enzyme that transfers ammonia during Amino Acid Metabolism and Biosynthesis of Amino Acids

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Using this enzyme:

Glutamate (NH2) + Oxaloacetate → Alpha Ketoglutarate + Aspartate (NH2)

Glutamate Synthase

Enzyme that transfers ammonia during Amino Acid Metabolism and Biosynthesis of Amino Acids

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Using this enzyme:

Glutamine (2 NH2) + Alpha Ketoglutarate + NADH → 2 Glutamate (NH2)

Oxaloacetate

A product of the Krebs Cycle and Glyoxylate Cycle

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Precursor of several amino acids

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Becomes Aspartate (NH2) during Amino Acid Metabolism due to the enzyme Transaminase

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Also converted to phsophoenolpyruvate, a precursor for glucose

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Produces the following for Biosynthesis of Amino Acids:


1. Aspartate


1. Asparagine
2. Lysine
3. Methionine
4. Threonine
5. Isoleucine

Anabolic Reactions

Includes:


1. Carbohydrate Metabolism
2. Lipid Metabolism
3. Amino Acid Metabolism
4. Nucleotide Metabolism

Alpha Ketoglutarate

A product of the Krebs Cycle

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A precursor for several amino acids

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Produces the following for Biosynthesis of Amino Acids


1. Glutamate


1. Proline
2. Glutamine
3. Arginine

Succinyl CoA

A product of the Krebs Cycle

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Required for synthesis of:


1. Cytochromes
2. Chlorophyll
3. Other Tetrapyrrole compounds

Acetyl CoA

A product of Krebs Cycle Preparation and Glyoxylate Cycle

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Pyruvic acid (3C) → acetyl CoA (2C) + CO2

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Necessary for fatty acid Biosynthesis

Succinate

A product of the Glyoxylate Cycle

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A key precursor in biosynthesis

Gluconeogenesis

Synthesis of glucose from phsophoenolpyruvate

Adenosine Diphosphoglucose (ADPG)

Precursor for Glycogen biosynthesis

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This + Glycogen → ADP + Glycogen-Glucose

Uridine Diphosphoglucose (UDPG)

Precursor of some glucose derivatives needed for biosynthesis of important polysaccharides


1. N-acetylglucosamine
2. N-acetylmuramic Acid

Biosynthesis of Amino Acids

Carbon skeletons come from Krebs Cycle or Glycolysis

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Ammonia comes from:


1. Dehydrogenase
2. Synthetase
3. Transaminase
4. Synthase

Pyruvate

A product of Glycolysis

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Produces the following for Biosynthesis of Amino Acids:


1. Alanine


1. Valine
2. Leucine

3-Phosphoglycerate

A product of Glycolysis

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Produces the following for Biosynthesis of Amino Acids


1. Serine


1. Glycine
2. Cysteine

Chorismate

A product of Glycolysis post-phosphoenolpyruvate

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Produces the following for Biosynthesis of Amino Acids:


1. Aromatic


1. Phenylalanine
2. Tyrosine
3. Tryptophan

Histidine

A product of Ribose 5-P used for Biosynthesis of Amino Acids

Biosynthesis of Fatty Acids

Made up of 2 carbon atoms at a time

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Requires:


1. Acyl Carrier Protein
2. NADPH

Acyl Carrier Protein

A protein required for the Biosynthesis of Fatty Acids

Synthesis of Pentose Sugar

Nucleotide anabolism

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Phosphogluconate pathway

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Pentose phosphate pathway

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Hexose monophosphate shunt

Biosynthesis of Pyrimidine

Nucleotide anabolism

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Orotic acid precursor

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Activated ribose is added

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UMP intermediate

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Products CTPT and TMP

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A Growth Factor

Biosynthesis of Purine

Nucleotide anabolism

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Starts from amino acids, CO2, and formyl groups

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Formyl Groups added w/ folic acid

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IMP intermediate forms AMP and GMP

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A Growth Factor

Methotrexate

Inhibitor of Nucleotide Synthesis

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Inhibits tetrahydrofolate to TMP

Aminopterin

Inhibitor of Nucleotide Synthesis

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Inhibits tetrahydrofolate to TMP

6-Mercaptopurine

Inhibitor of Nucleotide Synthesis

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Inhibits conversion of IMP to AMP

5 Fluoropyrimidine

Inhibitor of Nucleotide Synthesis

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Blocks conversion on UMP to TMP

Sulfonamides

Inhibitor of Nucleotide Synthesis

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Block folic acid synthesis

Nutrients

Supply of monomers (or precursors of) required by cells for growth

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2 types:


1. Macro
2. Micro

Macronutrients

Nutrients required in large amounts

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1. Carbon
2. Nitrogen
3. Phosphorus
4. Sulfur
5. Potassium
6. Magnesium
7. Calcium
8. Sodium

Carbon

Macronutrient

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Required by all cells and major in all classes of macromolecules

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Heterotrophs obtain this via organic means

Autotrophs obtain this via CO2

Nitrogen

Macronutrient

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Key element in:


1. Proteins
2. Nucleic Acids
3. Many more cell constituents

Phosphorus

Macronutrient

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Used in synthesis of:


1. Nucleic Acids
2. Phospholipids

Sulfur

Macronutrient

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Used in:


1. This-containing Amino Acids like Cysteine and Methionine
2. Vitamins like Thiamine, Biotin, Lipoic Acid
3. Coenzyme A
4. Proteins

Potassium

Macronutrient

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Required by enzymes for activity

Magnesium

Macronutrient

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Stabilizes:


1. Ribosomes
2. Membranes
3. Nucleic Acids

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Required for many enzymes

Calcium

Macronutrient

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Helps stabilize cell walls in microbes

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Plays key role in heat stability of endospores

Sodium

Macronutrient

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Required by certain microbes (marine) to retain water and collect water in sodium-rich environments

Micronutrients

Nutrients needed in small amounts

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1. Iron
2. Other trace elements
3. Growth Factors

Iron

Micronutrient

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Key component of cytochromes and FeS proteins involved in ETS

Growth Factors

Micronutrients

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Organic compounds required in small amounts by certain organism

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1. Vitamins
2. Amino Acids
3. Purines
4. Pyrimidines

Vitamins

Most commonly required Growth Factor Micronutrient

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Most function as coenzymes

Culture Media

Nutrient solutions used to grow microbes in the lab

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Liquid or semi solid or solid

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2 broad classes:


1. Defined
2. Complex

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Types:


1. Enriched
2. Differential
3. Selective

Defined Media

Type of Culture Media

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Precise chem composition is known

Complex Media

Type of Culture Media

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Composed of digests of chemically undefined substances

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Ex.

yeast

meat extracts

Enriched Media

Type of Culture Media

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Contains complex media plus addition nutrients

Differential Media

Type of Culture Media

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Allows multiple types of bacteria to grow but displays visible differences in how they grow

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Ex.

Spirit Blue Agar

Starch Agar

Skim Milk Agar

Starch Agar

An example of Differential Media

Skim Milk Agar

An example of Differential Media

Selective Media

A type of Culture Media

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Inhibits the growth of certain bacteria

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Ex.

Asparagine Agar

Phenyl Ethyl Alcohol Agar

Asparagine Agar

Example of Selective Media

Phenyl Ethyl Alcohol Agar

Example of Selective Media

Salmonella Shigella Agar

Example of Selective and Differential Media

MacConkey Agar

Example of Selective and Differential Agar

Mannitol Salts Agar

Example of Selective and Differential Agar

Pure Culture

Contains only one type of microbe

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Obtained via:


1. Growing on solid media
2. Using aseptic technique
3. Isolation