Bacterial Power-houses: Metabolism Review

Flashcards covering key vocabulary related to metabolism, enzymes, redox reactions, carbohydrate catabolism, alternate energy pathways, and biosynthesis pathways from the lecture notes.

Metabolism

The sum of all chemical reactions within a living organism.

Catabolism

The breakdown of complex organic compounds into simpler ones, liberating energy.

Anabolism

The building of complex molecules from simpler ones, requiring energy.

Exergonic Reactions

Chemical reactions associated with catabolism that release energy.

Dehydration Reactions

Reactions involved in anabolism that release water.

Endergonic Reactions

Chemical reactions associated with anabolism that require energy.

ATP (Adenosine Triphosphate)

The energy currency of the cell.

Collision Theory

Explanation of how chemical reactions occur and how certain factors affect the rates of these reactions where molecules in constant motion collide.

Activation Energy

The amount of energy needed to disrupt an electron configuration so that a reaction occurs.

Reaction Rate

The frequency of collisions containing sufficient energy to start a reaction.

Enzymes

Catalysts which speed up chemical reactions by lowering activation energy without being altered themselves; typically large globular proteins.

Catalysts

Substances that speed up chemical reactions without being altered themselves; enzymes are a type of catalyst.

Substrate

The specific substance upon which an enzyme acts.

Active Site

A specific region on an enzyme optimized for binding its substrate.

Competitive Inhibitors

Substances that fill the active site of an enzyme and compete with the substrate for binding.

Noncompetitive Inhibitors

Substances that bind with another part of the enzyme, changing the shape of the active site through allosteric inhibition.

Allosteric Inhibition

The process where a noncompetitive inhibitor binds to an enzyme at a site other than the active site, altering the active site's shape.

Feedback Inhibition

A process where the enzyme product acts as an inhibitor, typically noncompetitive, preventing the cell from wasting resources on more product than it needs.

Ribozymes

RNA molecules discovered in 1982 that function as catalysts, have active sites, and are not used up in chemical reactions; involved in cutting and splicing RNA and protein synthesis.

Oxidation-Reduction Reactions (Redox Reactions)

Coupled reactions where when one substance is being oxidized (loses electrons), another is being simultaneously reduced (gains electrons).

Oxidation

The loss of electrons from a molecule.

Reduction

The gain of electrons by a molecule.

Substrate-Level Phosphorylation

A method of ATP generation where a phosphate is transferred directly from a phosphorylated compound to ADP.

Oxidative Phosphorylation

A method of ATP generation where electrons are transferred from an organic compound (e.g., reduced NADH) to a series of electron carriers, releasing energy to attach inorganic phosphate to ADP.

Glycolysis

The oxidation of glucose to pyruvic acid, producing NADH and ATP, typically divided into a preparatory stage and an energy-conserving stage.

Krebs Cycle (Citric Acid Cycle)

A metabolic pathway that oxidizes acetyl CoA into CO2, producing NADH, FADH2, and ATP.

Electron Transport Chain (ETC)

A series of carrier molecules that take NADH and FADH2 from previous reactions to produce ATP through chemiosmosis.

Chemiosmosis

The process by which the Electron Transport Chain produces ATP, driven by the movement of protons down their concentration gradient through ATP synthase.

Aerobic Respiration

Respiration where O2 is the final electron acceptor in the electron transport chain, resulting in the production of water.

Anaerobic Respiration

Respiration where the final electron acceptor is not O2, generally yielding less ATP than aerobic respiration.

Chemotrophs

Organisms that derive their energy from the breakdown of chemical compounds.

Phototrophs

Organisms that utilize light energy from the sun to generate chemical energy through photosynthesis.

Photosynthesis

The process by which phototrophs convert light energy into chemical energy, creating sugars and oxygen (or sulfur in some bacteria).

Pentose Phosphate Pathway (PPP)

An alternative metabolic pathway that processes 5-carbon sugars and provides precursors for nucleic acids and amino acids, working in conjunction with glycolysis.

Entner-Doudoroff Pathway (ED pathway)

An alternative pathway to glycolysis that still breaks down glucose to pyruvate, used by some bacteria like Pseudomonas and E.coli.

Fermentation

A process that releases energy from sugars or other organic molecules, does not require oxygen, does not use the TCA cycle or ETS, uses an organic molecule as the terminal electron acceptor, and produces small amounts of energy.

Lipases

Enzymes that separate glycerol from fatty acid chains in lipids, allowing them to be converted into intermediates for glycolysis or the acetyl CoA steps.

Proteases and Peptidases

Extracellular enzymes that break down complex proteins into component amino acids for uptake into the cell.

Deamination

The removal of an amine group from an amino acid intermediates during protein catabolism.

Transamination

The transfer of an amine group from a pre-existing amino acid to an intermediate during amino acid biosynthesis.

Light Reactions

The initial stages of photosynthesis where energy from the sun is used to generate ATP and reduce NAD+ to NADH, occurring in the thylakoids of chloroplasts.

Dark Reactions

The stages of photosynthesis where electrons carried by NADH and ATP are used to reduce CO2 into sugar and oxygen, occurring in the stroma of chloroplasts.

Polysaccharide Biosynthesis

The process where bacteria store glucose as glycogen by removing glucose-6-phosphate from glycolysis and linking them together when glucose is plentiful.

Lipid Biosynthesis

The process of creating lipids, where glycerol can be derived from glycolysis intermediates and fatty acids from Acetyl CoA.

Amino Acid Biosynthesis

The production of amino acids by drawing intermediates from glycolysis and the Krebs cycle, sometimes involving amination or transamination.

Nucleic Acid Biosynthesis

The process of creating nucleotides for active cells, often by drawing intermediates from the pentose phosphate pathway and using certain amino acids.