Botany: Respiration in Plants - Glycolysis

Vocabulary flashcards covering the key terms, enzymes, steps, and energetic calculations of glycolysis from Lecture 02 of Respiration in Plants.

Glycolysis

A 10-step metabolic pathway occurring in the cytoplasm that involves the partial (incomplete) oxidation of a glucose molecule ($6\text{C}$) into two molecules of pyruvic acid ($3\text{C}$) without requiring oxygen.

EMP Pathway

An alternate name for glycolysis, named after the three scientists who elucidated the scheme: Gustav Embden, Otto Meyerhof, and J. Parnas.

Invertase

The enzyme that converts sucrose (invert sugar, a $12\text{C}$ sugar) into glucose ($6\text{C}$) and fructose ($6\text{C}$), enabling them to enter the glycolytic pathway.

Hexokinase

The enzyme that catalyzes the first irreversible reaction of glycolysis, converting glucose into glucose-6-phosphate while utilizing one molecule of ATP.

Phosphofructokinase-1 (PFK-1)

The pacemaker or rate-determining enzyme of glycolysis that catalyzes the irreversible conversion of fructose-6-phosphate into fructose-1,6-bisphosphate using one ATP molecule.

Universal Pathway

A designation given to glycolysis because it occurs in the cytoplasm of virtually all living cells—both prokaryotes and eukaryotes, as well as aerobes and anaerobes—without requiring free $\text{O}_2$.

Irreversible Steps of Glycolysis

Steps 1, 3, and 10 of the glycolytic pathway, which include the phosphorylation of glucose, the phosphorylation of fructose-6-phosphate, and the conversion of phosphoenolpyruvate (PEP) to pyruvate.

Obligate Anaerobes

Organisms, such as Clostridium and Fusobacterium, that strictly require anaerobic conditions and rely on pathways like glycolysis for energy generation in the absence of free $\text{O}_2$.

Facultative Anaerobes

Organisms, such as Mycoplasma, that can adapt to and survive under anaerobic conditions to produce energy even though they can exist in varied environments.

Net ATP Gain of Glycolysis

The direct net formation of $2\text{ ATP}$ for immediate use (gross gain of $4\text{ ATP}$ minus $2\text{ ATP}$ consumed), which equals a total gain of $8\text{ ATP}$ when including the $6\text{ ATP}$ generated via ETS from the $2\text{ NADH} + \text{H}^+$ produced.