Biochemistry: ATP and Metabolic Reactions

In active cells, 1 to 2 million ATP molecules are hydrolyzed per second.

Catabolic reactions provide energy to regenerate ATP from ADP and inorganic phosphate (Pi).

ATP stores energy used in anabolic reactions.

Catabolic reactions in food provide the energy for creating ATP.

Only about 1 gram of ATP is present in cells at any given time, but a large amount can be hydrolyzed in a day.

Energy transformations linking energy-releasing reactions with energy-requiring reactions.

ATP (Adenosine Triphosphate) is a molecule with 3 phosphate groups. A significant amount of energy is stored in the phosphate bonds.

ATP provides energy needed for anabolic reactions, which build up complex molecules, such as proteins.

NAD+ is reduced to NADH and H+ when it gains electrons (a reducing agent) during metabolic reactions involving oxidation of alcohols like ethanol to aldehydes and ketones

NAD+ plays a key role in metabolic reactions by facilitating the formation of carbon-oxygen double bonds.

Ethanol is oxidized to acetaldehyde (ethanal) and NAD+ is reduced to NADH during a metabolic reaction .

FAD is a coenzyme that contains ADP and riboflavin, crucial for redox reactions, and is reduced to FADH2

FAD is reduced when it accepts two hydrogen atoms (2H+), changing to FADH2, during a redox reaction

FAD accepts hydrogen during a reaction that converts a carbon-carbon single bond to a double bond.

The conversion of succinate to fumarate in the citric acid cycle, involving FAD as a coenzyme.

Coenzyme A is composed of pantothenic acid, phosphorylated ADP, and aminoethanethiol.

Coenzyme A prepares acyl groups (like acetyl) for enzyme reactions, especially linking acetyl group to enzymes.

The reactive part of coenzyme A is the thiol (¬SH) group.

A two-carbon acetyl group bonds to the thiol group in CoA, forming the energy-rich acetyl CoA.

The addition of an acetyl group to coenzyme A results in a thioester bond formation.

Coenzyme A gets reduced (gains electrons) when an acetyl group is added.

The process where electrons from NADH and FADH2 are passed along a chain of carriers, releasing energy used to make ATP.

The process where ATP is synthesized from ADP and Pi using the energy released during electron transport.

The organelle where electron transport and oxidative phosphorylation take place.

The membrane within a mitochondrion where electron carriers are embedded.

The outer layer of a mitochondrion.

The space between the inner and outer membranes of a mitochondrion.

The innermost compartment of a mitochondrion where the citric acid cycle takes place.

The total amount of ATP produced from the complete oxidation of one glucose molecule.

The aldehyde group of glyceraldehyde-3-phosphate is oxidized to a carboxyl group, while NAD+ is reduced to NADH. A phosphate group (Pi) is added to the carboxyl group to form 1,3-bisphosphoglycerate.

NAD+ is a coenzyme that accepts electrons during the oxidation of glyceraldehyde-3-phosphate, becoming reduced to NADH.

A high-energy compound formed by the oxidation of glyceraldehyde-3-phosphate, containing two phosphate groups.

A phosphate group from 1,3-bisphosphoglycerate is transferred to ADP, producing ATP and 3-phosphoglycerate.

3-phosphoglycerate is converted into 2-phosphoglycerate by moving the phosphate group from carbon 3 to carbon 2.

2-phosphoglycerate loses a water molecule to form phosphoenolpyruvate, gaining a high-energy phosphate bond.

A high-energy compound formed through dehydration, containing a phosphate group with a high potential energy.

A phosphate group from phosphoenolpyruvate is transferred to ADP, generating ATP and pyruvate.

When oxygen is plentiful, pyruvate, a product of glycolysis, moves into the mitochondria to undergo further oxidation.

Within the mitochondria, pyruvate is oxidized, losing a carbon atom as carbon dioxide (CO2).

Acetyl CoA is a crucial intermediate in many metabolic pathways, including the citric acid cycle (Krebs cycle).

Glucose, obtained from the digestion of polysaccharides, is broken down in glycolysis to pyruvate.

Oxygen plays a crucial role in aerobic respiration, enabling the complete breakdown of glucose and yielding a greater energy output (ATP).

Aerobic respiration occurs in the presence of oxygen and produces far more ATP than anaerobic respiration, which happens in the absence of oxygen.