Glycolysis Overview

This flashcard set covers key vocabulary and concepts related to glycolysis, including enzymes, transporters, and metabolic processes.

Glycolysis

A metabolic pathway that converts glucose into pyruvate, producing ATP and NADH.

Substrate Level Phosphorylation

The direct synthesis of ATP from ADP without involvement of an electron transport chain.

ATP

Adenosine triphosphate, the primary energy carrier in cells.

NADH

Reduced form of nicotinamide adenine dinucleotide, an important cofactor in redox reactions.

Hexokinase

An enzyme that catalyzes the phosphorylation of glucose to glucose-6-phosphate.

Phosphofructokinase (PFK)

A key regulatory enzyme in glycolysis that converts fructose-6-phosphate to fructose-1,6-bisphosphate.

Pyruvate Kinase

An enzyme that catalyzes the final step of glycolysis, converting phosphoenolpyruvate to pyruvate.

Covalent Modification

A regulatory mechanism involving the addition or removal of chemical groups to enzymes.

Allosteric Regulation

The regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site.

Fermentation

An anaerobic process that allows cells to maintain ATP production in the absence of oxygen.

Pentose Phosphate Pathway

A metabolic pathway parallel to glycolysis that generates NADPH and ribose-5-phosphate.

GLUT1

A glucose transporter primarily responsible for basal glucose uptake in most cells.

GLUT2

A glucose transporter found in the liver and pancreas that helps regulate blood glucose levels.

GLUT4

An insulin-sensitive glucose transporter found in adipose tissue and muscle.

Lactate

The end product of anaerobic glycolysis in muscle cells during intense exercise.

2,3-bisphosphoglycerate (2,3-BPG)

A glycolytic intermediate that lowers oxygen affinity of hemoglobin.

Arsenate

A compound that can inhibit glycolysis by substituting for phosphate.

Isomerization

The process of converting one isomer into another, important in glycolytic reactions.

Enzyme Isozymes

Different forms of an enzyme that catalyze the same reaction but may have different regulatory properties.

Glyceraldehyde-3-phosphate Dehydrogenase (GAPDH)

The first enzyme in glycolysis that catalyzes an oxidation reaction.

Phosphoglycerate Kinase (PGK)

The enzyme that catalyzes the transfer of a phosphate group to ADP to form ATP.

Phosphoglycerate Mutase (PGM)

An enzyme that transfers a phosphate group within a molecule to convert 3-PG to 2-PG.

Enolase

An enzyme that catalyzes the dehydration of 2-PG to phosphoenolpyruvate.

Lactate Dehydrogenase

An enzyme that converts pyruvate to lactate during anaerobic respiration.

Fructose Metabolism

The process by which fructose is converted to intermediates that enter glycolysis.

Alternative Entry Points

Other pathways through which substrates like fructose and galactose can enter glycolysis.

Hexokinase vs Glucokinase

Hexokinase has a low Km and is active in most tissues, whereas glucokinase has a higher Km and is found in liver and pancreatic cells.

Energy Production

The net gain of 2 ATP molecules from the conversion of one glucose molecule during glycolysis.

Pyruvate Formation

The final product of glycolysis that can enter the Krebs cycle or be converted to lactate or ethanol.

Overall Reaction of Glycolysis

Glucose + 2 NAD+ + 2 ADP + 2 Pi → 2 Pyruvate + 2 NADH + 2 ATP.

Pasteur Effect

The observation that glucose utilization decreases in the presence of oxygen.

Regulators of PFK

Citrate (negative modulator) and Fructose-2,6-Bisphosphate (positive modulator).

Shunt Pathway in Red Blood Cells

The pathway involving 2,3-BPG which helps offload oxygen from hemoglobin.