Micro Metabolism

Unit Metabolism for Micro 251 for exam 2

Metabolism

is the collective total of ALL chemical reactions that occur within the cell/organism

Catabolism

large molecules that are broken down into smaller once

• Breaking down

• Releases energy

• Hydrolysis ( use water to break bonds)

• Exergonic ( reactions produce more energy than consumed) (Releasing energy)

  ex: Digestion of food, aerobic cell respiration

Anabolism

building up small molecules into Large Molecules

• Building bonds

• Absorbing energy

• Dehydration synthesis (water is removed to create bonds)

• Endergonic (building to supply energy ) ( “reactions "consume more energy than produced) (storing energy)

  ex: Protein synthesis & DNA synthesis

ATP

Is the energy carrier molecule within cell

Adenosine Triphosphate

energy is transferred from one component to another within the system

• Energy currency

• transferring energy

• to and from reactions

  ** Anabolic and Catabolic reactions are “Coupled/Linked” by energy

Chemoheterotroph

use organic compounds as the carbon source and production of ATP

“Have to eat other things” (HETERO)

Ex: Animals, Fungi, Protozoa, and bacteria

Energy Source: Chemical

Carbon Source: Organic Compounds

Chemoautotroph

Oxidize inorganic molecules ( for energy ) to fix carbon dioxide into organic compounds

• energy from inorganic compounds

• carbon comes from Co2 Fixation

• "Auto” - Self

Ex: Hydrogen - Sulfur, Iron, Nitrogen, carbon monoxide-oxidizing bacteria

Energy Source: Chemical

Carbon Source: Inorganic

Photoheterotroph

Use light (Sun) as source of energy to produce ATP and use organic compounds as carbon source

• "Hetro” - eat other things

  Ex: Green and purple non-sulfur bacteria, heliobacteria

  Energy Source: Light

  Carbon Source: Organic Compound

Photoautotroph

Use light as source of energy to fix carbon dioxide into organic compounds

• Plants will collect energy from light (Sun)

• Carbon from Co2 fix

• ex: Cyanobacteria (group of photosynthetic bacteria that produce oxygen)

Ex: All plants, algae, cyanobacteria, and green and purple sulfur bacteria

Energy Source: Light

Carbon Source: Inorganic

Photosynthesis

Metabolic process that uses light energy to fix inorganic carbon dioxide (CO2) into organic compounds ( sugar) This may produce oxygen gas (Depends on the photosynthetic pathway)

organisms that use it ex: plants, algae, and certain types of bacteria called cyanobacteria

Enzymes

Is protein (macromolecule) that serves as a catalyst to “Speed up” chemical reactions by lowering activation energy for reaction to occur

• Enzymes are specific for their substrates

• Enzymes are sensitive to changes in their local environment (ph changes, temp, salinity)

Reduction

is the gain of electrons. When something has undergone reduction, it means that it has gained electrons.

-The Gain of Electron

-Reducing agent - Gain of election

Oxidation

is the removal of electrons (e^-) from an atom or molecule. When something has undergone oxidation, it means that it has lost electrons.

-The removal/lost of electron

-Oxidizing agents - lost of electron

Catabolism Electron carrier Molecules:

NAD+/NADH

FAD/FADH

Anabolism Electron carrier Molecules:

NADP+/NADPH

Microbes different ways to get ATP

Aerobic Respiration

Anaerobic Respiration

Fermentation

Lithotroph

Chemotroph that gets its energy from inorganic compounds (like reduced iron and H2s) Lithotrophy is only possible in microorganisms

Organotroph

Chemotroph that gets its energy from organic compounds, you think of this classification as chemoheterotroph

Carbohydrate Catabolism

The breakdown of sugar molecules to produce energy for cellular reactions

GLUCOSE is the most common carbohydrate for energy

(broken down for energy)

• 6 Carbon sugars has lots of energy in forms of electrons

Embden-Meyerof-Parnas (EMP) Pathway

Most common type of Glycolysis

Generates: 2 ATP, 2 NADH, 2 Pyruvates

Found in Animals

2 Pathways called: Energy Investment & Energy payoff Phase

Type of Glycolysis pathway

Entner-Doudoroff (ED) Pathway

Some bacteria use this particular type of Glycolysis

Generates: 1 ATP, 1 NADH, 1 NADPH

-Originally used for anabolism ( may be older than EMP pathway in evolutionally history)

Commonly associated with Gram-Negative bacteria

• Type of Glycolysis pathway

ATP produced by substrate-level phosphorylation

Means ATP is the primary energy carrier in biological system

a chemical reaction, without using oxygen or the electron transport chain.

Pentose Phosphate Pathway

Type of Glycolysis Pathway

used in Parallel with Glycolysis it generates 2 NADPH and ribulose-5-phosphate

• used primarily for anabolism ( of nucleotides , amino acids, and fatty acids)

  • 1st Intermediate in glycolysis

Glycolysis

• Location: Cytoplasm of the cell

• Oxygen requirement: Anaerobic (does not require oxygen)

• Starting molecule: Glucose (6-carbon sugar)

• End products:

  • 2 pyruvate (3-carbon molecules)

  • 2 ATP (net gain)

  • 2 NADH (electron carriers)

** see the handout

Inorganic Molecule

is a molecule that does NOT contain BOTH carbon and hydrogen

Stages of Aerobic Cellular Respiration

1) Glycolysis ( Split Glycose)

2) Pyruvate oxidation into acetyl-CoA (prepares it for Krebs)

3) Krebs Cycle ( More oxidation for energy)

4) Oxidative phosphorylation (electron transport chain and chemiosmosis) Oxygen is terminal electron acceptor

** see the handout

Pyruvate Oxidation

process of converting pyruvate (the end product of glycolysis) into acetyl-CoA, a molecule that enters the Krebs cycle.

It occurs in the cytoplasm

Products out ( Per Pyruvate) :

• 1 CO₂

•1 NADH

•1 Acetyl CoA

Citric Acid/ Krebs Cycle

Takes place in the Cytoplasm

Purpose: To extract high-energy electrons from carbon fuels (Acetyl-CoA)

Krebs cycle produce ( Per 1 Acetyl CoA)

• 1 ATP, 3 NADH, 1 FADH2 and 2 CO2

Oxidative Phosphorylation

Composed of two steps

-Electron Transport Chain

-Chemiosmosis

Electron Transport Chain

Located in the Plasma Membrane

Electron Carrier Molecule (NADH and FADH)

transfer their electrons to a series of proteins embedded in the cell membrane known as the ETC.

Oxygen is the Final electron acceptor and reduced to water

ETC Protons

Electrons pass through proteins in membrane

• Hydrogen ions (H+) pumped out into (Periplasmic space)

  • Space between the plasma cell membrane and the cell wall.

• Creating a Proton Gradient (Protons motive force)

Chemiosmosis

Chemiosmosis is the process where ATP is made using the energy from a proton (H⁺) gradient across a membrane.

Protons (H⁺) flow down their concentration gradient through a protein called ATP synthase, which uses that energy to synthesize ATP.

Aerobic Respiration Generate ATP # ?

-Regulate 32 ATP per glucose molecule

• 28 ATP is regulated from oxidative phosphate

Important Step-Wise harvest in Energy

Important to have a Step-By Step Wise Harvest

• Small steps to release energy from glucose

  • Releasing it all at once wont be efficient

• Also help with easy regulated by the microorganism

• Too much energy release if glucose oxidized all at once

2 Types of Cellular Respiration

Aerobic Cellular Respiration

Anaerobic Cellular Respiration

• Both types use process called inorganic terminal electron acceptor and undergo similar steps

Aerobic Cellular Respiration

Uses oxygen as a terminal electron acceptor

-Oxygen is inorganic

Oxygen is Used

Aerobic Respiration - Electron Transport Chain

Anaerobic Cellular Respiration

An inorganic molecule than oxygen (like sulfate or nitrate) in used as terminal electron acceptors

No Oxygen is Used

Nitrate is Used

Anaerobic Respiration - ETC

Stages/Steps of Anaerobic

Glycolysis ( Split Glucose)

Pyruvate Oxidation into acetyl-CoA ( Prepares it for Krebs)

Krebs Cycle ( more oxidation for energy)

Oxidative Phosphorylation (ETC and Chemiosmosis)

Non-Oxygen inorganic molecules is terminal electron acceptor

** Anaerobic uses fewer ATP molecules per glucose than aerobic cellular respiration

Inorganic molecules used in Anaerobic Respiration

Anaerobic:

Nitrate

Sulfate ion

Carbon Dioxide

Iron

hydrogen arsenate

Selenate ion

(Uses inorganic terminal electron acceptors)

Fermentation

Is the incomplete oxidation of Glucose to generate ATP

• Acceptor is organic

• Does not require Oxygen

• No oxidative phosphorylation

  • no ETC or Chemiosmosis is involved to generate ATP

• Organic electron acceptors

** FERMENTATION IS NOT ANAEROBIC Respiration

Steps for Fermentation

1 - Glycolysis (2 ATP generate for cellular use)

2 - Fermentation - Regeneration of NAD+ to be used in glycolysis again

• Generates 2 ATP

2 Types of Fermentation

Lactic Acid Fermentation

• End product are 2 molecules of lactic acid

Ethanol Fermentation

• End product are 2 molecules of Ethanol and 2 molecules of CO2

Homolactic Fermentation Types:

only produces lactic acid as waste product

Heterotactic Fermentation

Produces lactic acid, ethanol and acetic acid and CO2