B.4 Metabolic Pathways

Metabolic pathways

Sequential enzymatic reactions where the substrate of one step is the product of the previous one.

Glycolysis

The set of reactions that allows cells to use sugar as an energy source, resulting in pyruvate production.

ATP

A molecule that stores and provides energy for cellular processes.

Cellular respiration

The process by which cells break down food molecules and store energy in ATP. Also known as carbohydrate metabolism.

Phosphorylation

The addition of 2 phosphate groups to a molecule, which requires energy and converts glucose into fructose.

Pyruvate (PYR)

The final product of glycolysis, a three-carbon molecule with high chemical bond energy.

Krebs cycle

A series of reactions that further metabolizes acetyl CoA to release energy and produce ATP.

Electron transport chain (ETC)

A series of reactions that use oxygen to accept hydrogen and generate water, producing ATP.

Fermentation

An alternative metabolic pathway that occurs when oxygen is not available, converting PYR to either ethanol or lactic acid.

Lactic acid

A three-carbon molecule produced in animal cells during fermentation when oxygen is scarce.

Acetyl CoA

The two-carbon ionic form of acetic acid that enters the Krebs cycle after pyruvate dehydrogenation.

NADH

Nicotinamide adenine dinucleotide, a hydrogen carrier that plays a role in energy transfer during cellular respiration.

Oxaloacetate

A four-carbon molecule that combines with acetyl CoA to form citric acid in the Krebs cycle.

Ethanol

A two-carbon alcohol produced from pyruvate during fermentation in plant cells.

ADP

A molecule that can be converted to ATP when energy and inorganic phosphate are available.

Net production of ATP in glycolysis

Two molecules of ATP are generated, considering the two ATP consumed during phosphorylation.

Final products of complete aerobic respiration of one glucose molecule

36 molecules of ATP, 6 molecules of CO2, and 6 molecules of H2O.

LAD

lactic acid dehydrogenase, enzyme that converts PYR into lactate by adding hydrogen.

PAD

pryucvic acid dehydrogenase , removes carbon and hydrogen atom from pyurvic

Coenzyme A

transports acetyl group to the mitochondria.

prokaryotic cells

cell with no nuclei

eukaryotic cells

cells with a nuclei

aerobic

abundance of oxygen

anaerobic

lack of oxygen