Catabolism of Glucose Flashcards

This set of vocabulary flashcards covers the main metabolic pathways of glucose catabolism, including EMP, ED, and PPP, as well as the TCA cycle, electron transport chain, and diagnostic applications of fermentation.

EMP Pathway

Also known as the Embden-Meyerhof-Parnas Pathway, it is the most common form of glycolysis occurring in the cytoplasm in the presence or absence of $O_2$.

Entner-Doudoroff (ED) Pathway

A route of glucose catabolism studied mostly in prokaryotes that enables intestinal bacteria to feed on mucus.

Pentose Phosphate Pathway (PPP)

A pathway occurring in the cytosol that produces NADPH and a series of sugars like ribulose-5-phosphate for biosynthesis.

Glucose Activation Stage

The first stage of EMP where glucose is phosphorylated into fructose-1,6-bisphosphate, expending two ATP molecules.

Energy Yielding Stage

The second stage of EMP where fructose-1,6-bisphosphate is cleaved, producing four ATP via substrate-level phosphorylation, two NADH, and two pyruvate molecules.

Fructose 6-phosphate

A precursor metabolite of the EMP pathway used for peptidoglycan synthesis.

3-Phosphoglycerate

An EMP pathway metabolite that serves as a protein precursor for cysteine, glycine, and serine.

Tricarboxylic Acid (TCA) Cycle

Also known as the Krebs cycle, it catabolizes products of sugar breakdown to $CO_2$ and $H_2O$, generating NADH and $FADH_2$.

Gluconate

A sugar acid found in intestinal mucus that E. coli feeds on via the ED pathway.

Bacteroides thetaiotaomicron

A bacterium that induces colonic production of mucus to provide gluconate for catabolism.

NADH

An electron carrier that specifically transfers electrons to the electron transport chain.

NADPH

An electron carrier used by enzymes for biosynthesis, such as amino acid production.

Electron Transport Chain (ETC)

A series of membrane-embedded carriers that accept electrons from NADH and $FADH_2$ to release energy.

Proton Motive Force (PMF)

Generated by the ETC and used to drive ATP synthesis, active transport, and the rotation of flagella.

Fermentation

A form of anaerobic catabolism that uses endogenous, organic electron acceptors.

Phenol red

A pH indicator used in fermentation diagnostics that turns yellow under acidic conditions.

Durham tube

A specialized tube used in diagnostic applications to collect gas produced during fermentation.

E. coli O157:H7

A lethal contaminant of beef and vegetables that lacks the genes necessary to ferment sorbitol.

Sorbitol MacConkey agar

A diagnostic medium where red colonies indicate the fermentation of sorbitol.