Biochemistry: Glucose Metabolism Lecture

A monosaccharide (simple sugar) that is the primary energy source for most cells.

A polysaccharide (complex sugar) that acts as a medium-term energy store in the body. It is primarily composed of glucose units linked together.

The metabolic pathway that breaks down glucose into pyruvate. It occurs in the cytosol of all cells and involves a series of 10 enzymatic reactions.

The process of generating ATP from ADP using the energy released from breaking down high-energy phosphate molecules within the glycolysis pathway.

An enzyme that catalyzes the reversible interconversion of glucose and glucose 6-phosphate. Found in all tissues.

An enzyme that catalyzes the conversion of glucose to glucose 6-phosphate. Found primarily in the liver.

The stage of glycolysis that involves the addition of phosphate groups, requiring the use of ATP.

The key regulatory enzyme in the glycolysis pathway. It catalyzes the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate, a committed step in glycolysis.

A product of glycolysis, a three-carbon molecule that can be further processed in the citric acid cycle or under anaerobic conditions.

A process that regenerates NAD+ from NADH under anaerobic conditions, allowing glycolysis to continue even in the absence of oxygen. It converts pyruvate to lactate.

An enzyme that catalyzes the conversion of pyruvate to lactate, a key step in anaerobic metabolism.

The process used by red blood cells to generate energy as they lack mitochondria for aerobic respiration.

The process by which glucose is converted into glycogen, providing a storage form for energy in the liver and muscles.

The process by which glycogen is broken down into glucose, releasing stored energy.

The liver and muscle have different isoforms of the enzyme, resulting in different affinities for glucose. The liver's higher Km means it requires higher glucose concentrations for optimal activity, allowing it to store excess glucose.

Phosphohexose isomerase converts glucose 6-phosphate to fructose 6-phosphate, changing the sugar from an aldose to a ketose.

Phosphofructokinase (PFK) catalyzes the phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate, using ATP as an energy source.

Phosphofructokinase (PFK) is a key regulatory enzyme in glycolysis, controlling the rate of sugar breakdown. It's a crucial step for controlling energy production.

Aldolase splits fructose 1,6-bisphosphate into two 3-carbon units: glyceraldehyde 3-phosphate and dihydroxyacetone phosphate.

Dihydroxyacetone phosphate is converted to glyceraldehyde 3-phosphate, ensuring that all glucose-derived carbon eventually becomes glyceraldehyde 3-phosphate for further processing in glycolysis.

Glyceraldehyde 3-phosphate dehydrogenase converts glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate, producing NADH and releasing an inorganic phosphate.

The NADH generated by glyceraldehyde 3-phosphate dehydrogenase is later used in oxidative phosphorylation to produce ATP, providing energy for the cell

The enzyme that catalyzes the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate, generating ATP in the process.

The molecule produced from the reaction catalyzed by phosphoglycerate kinase.

The transfer of a phosphate group within a molecule, changing its chemical structure.

The enzyme that catalyzes the transfer of a phosphate group from the 3-position to the 2-position of glycerate.

The molecule produced from the reaction catalyzed by phosphoglycerate mutase.

The enzyme that catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate.

The molecule produced from the reaction catalyzed by enolase, a high-energy phosphate compound that will be used in the next step of glycolysis.

ATP is a key regulator of glycolysis. High ATP levels inhibit phosphofructokinase, slowing down the process. This is a feedback mechanism that ensures energy production is balanced with cell needs.

Brain cells heavily depend on glycolysis for their energy supply. Unlike other tissues, brain cells can't use fats for energy.

The Warburg effect describes cancer cells' preference for anaerobic glycolysis, even in the presence of oxygen. This abnormal metabolism allows them to grow and proliferate rapidly.

The Warburg effect can be helpful in diagnosing and treating cancer. Monitoring lactate levels and targeting the Warburg effect pathway may hold therapeutic potential.

Glycolysis is a central pathway, present in all tissues, that breaks down glucose for energy. It can operate in both aerobic and anaerobic conditions.

Under aerobic conditions, glycolysis produces pyruvate, which can enter the mitochondria for further ATP production, yielding more energy.

Under anaerobic conditions, glycolysis produces lactate as the end product, yielding less energy than aerobic glycolysis.

ATP is an energy currency for cells. The enzyme involved in ATP production during glycolysis is irreversible, meaning it can only proceed in one direction.

Glycolysis is a metabolic process that breaks down glucose to produce ATP. The early stages of glycolysis require 2 ATP, but the later stages generate 4 ATP, resulting in a net gain of 2 ATP.

When there's limited oxygen, pyruvate doesn't completely break down into CO2, instead it's converted to lactate. This conversion regenerates NAD+ which is necessary for glycolysis to continue.

Lactate dehydrogenase is an enzyme that catalyzes the reversible conversion of pyruvate to lactate using NADH and H+ ions. It's important for maintaining NAD+ levels in the body.

Pyruvate can be converted to lactate, acetyl-CoA, or ethanol depending on the presence of oxygen and the availability of mitochondria. With oxygen, pyruvate enters the citric acid cycle, but without oxygen, it turns into lactate or ethanol.

Glycolysis is regulated by both allosteric and hormonal mechanisms. Allosteric regulation involves direct interactions of metabolites with enzymes, affecting their activity. Hormonal control involves signals from hormones that influence enzyme activity.

Feedback inhibition is a type of allosteric regulation where the product of a pathway inhibits an enzyme earlier in the pathway. Phosphofructokinase, a key enzyme in glycolysis, is inhibited by ATP, citrate, and fructose 6-phosphate.

Allosteric control of phosphofructokinase involves the binding of molecules like ATP, citrate, and AMP to the enzyme, altering its activity. If the cell has a high energy level (high ATP, high citrate), glycolysis slows down. If the cell needs more energy (high AMP), glycolysis speeds up.

The net gain of ATP produced from anaerobic glycolysis is 2 ATP molecules per glucose molecule.

Glycolysis is the breakdown of glucose into pyruvate.

Anaerobic means without oxygen. Anaerobic glycolysis occurs in the cytoplasm of cells.

ATP (adenosine triphosphate) is the primary energy currency of cells. It is used to power various cellular processes.

The process of glycolysis involves a series of enzymatic reactions. It can be divided into two main phases: 1. Energy investment phase: 2 ATP molecules are used. 2. Energy payoff phase: 4 ATP molecules are produced.

During anaerobic glycolysis, pyruvate is converted to lactate (lactic acid).

The process of glycolysis begins with glucose and ends with pyruvate.

The net gain of ATP from aerobic glycolysis is 38 ATP molecules per glucose molecule. This is significantly more than the anaerobic yield.

The electron transport chain (ETC) is a series of protein complexes that use electrons to generate ATP in aerobic glycolysis.

The process of aerobic respiration involves glycolysis, the Krebs cycle, and the electron transport chain, all occurring within the mitochondria of the cell.