Integrated SequencePhysics Chemistry Organic Biology

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Module 12 in the Syllabus

Biosynthesis of Macromolecules Images
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Question Drill for Integration of Metabolism
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Conceptual Vocabulary
GluconeogenesisGluconeogenesis is the generation of glucose from non-sugar carbon substrates like pyruvate, lactate, glycerol, and glucogenic amino acids.
Glucose-6-phosphateGlucose 6-phosphate (also known as Robison ester) is glucose sugar phosphorylated on carbon 6.
AminationAmination is the process by which an amine group is introduced into an organic molecule.
Pentose phosphate pathwayThe pentose phosphate pathway is a process that serves to generate NADPH and the synthesis of pentose sugars.
Futile cycleA futile cycle is when two metabolic pathways run simultaneously in opposite directions and have no overall effect other than wasting energy.
GlycogenesisGlycogenesis is the process of glycogen synthesis, in which glucose molecules are added to chains of glycogen.
GlycogenolysisGlycogenolysis is the catabolism of glycogen by removal of a glucose monomer and addition of phosphate to produce glucose-1-phosphate.
Isopentenyl pyrophosphateIsopentenyl pyrophosphate is an intermediate in the mevalonate pathway used by organisms in the biosynthesis of terpenes and terpenoids, and thence a host of other substances such as steroids.
SqualeneThe triterpene isoprenoid compound squalene is the biochemical precursor to the whole family of steroids.
Pyruvate carboxylasePyruvate carboxylase is an enzyme of the ligase class that catalyzes the irreversible carboxylation of pyruvate to form oxaloacetate. Oxaloacetate can then either proceed to the citric acid cycle or to gluconeogenesis.
Mevalonate pathwayThe mevalonate pathway is an important cellular metabolic pathway for the production of dimethylallyl pyrophosphate and isopentenyl pyrophosphate, substances which are the building blocks of a large variety of biomolecules.
Mevalonic acidMevalonic acid is a key organic compound in biochemistry. It is a precursor in the biosynthetic pathway, known as the HMG-CoA reductase pathway, that produces terpenes and steroids.
TransaminationTransamination (or aminotransfer) is the reaction between an amino acid and an alpha-keto acid in which the amino group is transferred from the former to the latter.
Urea cycleThe urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions occurring in many animals that converts ammonia into a less toxic substance.
TransketolaseThe enzyme transketolase connects the pentose phosphate pathway to glycolysis in mammals, feeding excess sugar phosphates into the main carbohydrate metabolic pathways.
Glucose isomeraseGlucose isomerase is an enzyme that catalyzes the conversion of glucose into fructose or the reverse process.
Uridine diphosphate glucoseUridine diphosphate glucose is a nucleotide that is used as an activated form of glucose, a substrate for glycosyltransferases.
HMG-CoA reductaseHMG-CoA reductase is the first enzyme of the mevalonate pathway that produces terpenes, terpenoids, steroids and various other biomolecules.
TransaminaseA transaminase or an aminotransferase is an enzyme that catalyzes the transfer of an amine group between an amino acid and an alpha-keto acid.
Ribulose 5-phosphateRibulose 5-phosphate is one of the end products of the pentose phosphate pathway. It is also an intermediate in the Calvin cycle.
Cori cycleThe Cori cycle refers to the cycling of lactate produced by red blood cells and muscle during anaerobic respiration back into glucose.
Glucose cycleThe glucose cycle occurs primarily in the liver and is the dynamic equilibrium between glucose and glucose 6-phosphate.
Dimethylallyl pyrophosphateDimethylallyl pyrophosphate is an intermediate product of both mevalonic acid pathway and DOXP/MEP pathway. It is an isomer of isopentenyl pyrophosphate and exists in virtually all life forms.
Transsulfuration pathwayThe transsulfuration pathway is a metabolic pathway that converts cysteine to homocysteine, through the intermediate cystathionine.
Alanine cycleThe alanine cycle is quite similar to the Cori cycle. When muscles produce lactate during times of decreased oxygen, they also produce alanine which is shuttled to the liver where it is used to make glucose.
Polyol pathwayUnused glucose enters the polyol pathway when aldose reductase reduces it to sorbitol.
Advanced terms that may appear in context in MCAT passages
Pyridoxal phosphatePyridoxal-phosphate (vitamin B6) is a coenzyme in all transamination reactions, and in some decarboxylation and deamination reactions of amino acids.
Glucose-6-phosphate dehydrogenaseGlucose-6-phosphate dehydrogenase is an enzyme in the pentose phosphate pathway converting glucose-6-phosphate into 6-phosphoglucono-delta-lactone.
6-phosphogluconolactonase6-phosphogluconolactonase is an enzyme in the pentose phosphate pathway, converting 6-phosphogluconolactone to 6-phosphogluconate.
Phosphogluconate dehydrogenasePhosphogluconate dehydrogenase is an enzyme in the pentose phosphate pathway, forming ribulose 5-phosphate from 6-phosphogluconate.
Phosphopentose isomerasePhosphopentose isomerase is an enzyme which converts ribulose 5-phosphate (a ketose) to ribose 5-phosphate (an aldose).
Phosphopentose epimerasePhosphopentose epimerase is an enzyme which intraconverts ribulose 5-phosphate and xylulose 5-phosphate, playing a role in the Calvin cycle and the pentose phosphate pathway.
Glyoxylate cycleThe glyoxylate cycle allows some organisms to use fats for the synthesis of carbohydrates, a task which most vertebrates, including humans, cannot perform.

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