Glycolysis and Metabolism

This set of flashcards covers key vocabulary and concepts related to glycolysis, its regulation, and fermentation processes in metabolism.

Glycolysis

The universal pathway for extracting energy from glucose, which can operate with or without oxygen.

Pyruvate

The end product of glycolysis, which can be further metabolized under aerobic or anaerobic conditions.

Lactate

A temporary solution produced during anaerobic glycolysis that regenerates NAD⁺.

Aerobic

Referring to processes that require oxygen.

Anaerobic

Referring to processes that do not require oxygen.

ATP investment phase

The first phase of glycolysis where 2 ATP are used to convert glucose into a more reactive form.

Cleavage phase

The second phase of glycolysis where glucose is split into two three-carbon molecules.

Payoff phase

The third phase of glycolysis where ATP and NADH are produced.

Fermentation

A metabolic process that regenerates NAD⁺ from NADH under anaerobic conditions.

Hexokinase

The enzyme that phosphorylates glucose to form glucose-6-phosphate, trapping glucose in the cell.

Induced fit

An enzyme mechanism that ensures specificity by changing shape to fit the substrate upon binding.

Phosphofructokinase (PFK)

The main regulatory enzyme in glycolysis that catalyzes the irreversible conversion of fructose 6-phosphate to fructose 1,6-bisphosphate.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH)

The enzyme that catalyzes the oxidation of glyceraldehyde-3-phosphate to form NADH and 1,3-bisphosphoglycerate.

Pyruvate kinase

The enzyme that catalyzes the conversion of phosphoenolpyruvate to pyruvate, producing ATP in the process.

Cori Cycle

The metabolic pathway where lactate produced in muscles is converted back to glucose in the liver.

NAD⁺ regeneration

The process by which NADH is converted back to NAD⁺ to ensure glycolysis can continue.

Fructose-2,6-bisphosphate

A key regulatory molecule that activates phosphofructokinase in the liver.

Control points

Irreversible steps in a metabolic pathway that are major regulation sites, such as hexokinase, PFK, and pyruvate kinase.

Acetyl-CoA

A central metabolite that links glycolysis to the citric acid cycle in aerobic respiration.

Enzyme efficiency

The increased rate of biochemical reactions when enzymes are organized into complexes.

Thioester intermediate

A high-energy covalent bond formed during the oxidation process in glycolysis that facilitates energy transfer.

Lactic acid fermentation

The anaerobic process where glucose is metabolized to lactate, regenerating NAD⁺.

Alcoholic fermentation

The process by which yeast convert glucose into ethanol and CO₂, regenerating NAD⁺.

Stereoisomers of aldohexoses

Different structural forms of six-carbon sugars that can undergo metabolic processes.

Glycolytic intermediates

The various metabolites produced during the glycolysis pathway that can enter other metabolic pathways.

High-fructose corn syrup

A sweetener derived from corn that is metabolically dangerous due to bypassing key control points in glycolysis.

Obligate anaerobes

Organisms that cannot survive in the presence of oxygen.

Advanced glycation end products (AGEs)

Compounds formed by the non-enzymatic glycosylation of proteins, potentially leading to cellular damage.