anabolic pathways

Examples of anabolic pathways in the following topics:

• Metabolic Pathways

  • An anabolic pathway requires energy and builds molecules while a catabolic pathway produces energy and breaks down molecules.
  • The first of these processes requires energy and is referred to as anabolic.
  • Anabolic pathways require an input of energy to synthesize complex molecules from simpler ones.
  • One example of an anabolic pathway is the synthesis of sugar from CO2.
  • Anabolic pathways are those that require energy to synthesize larger molecules.

• Repression of Anabolic Pathways

  • Repression of anabolic pathways is regulated by altering transcription rates.

• Steroids

  • Steroid biosynthesis is an anabolic metabolic pathway that produces steroids from simple precursors.
  • A unique biosynthetic pathway is followed in animals compared to many other organisms, making the pathway a common target for antibiotics and other anti-infective drugs.
  • The non-mevalonate pathway or 2-C-methyl-D-erythritol 4-phosphate/1-deoxy-D-xylulose 5-phosphate pathway (MEP/DOXP pathway) of isoprenoid biosynthesis is an alternative metabolic pathway leading to the formation of isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP).
  • The classical mevalonate pathway or HMG-CoA reductase pathway is an important cellular metabolic pathway present in all higher eukaryotes and many bacteria.
  • In contrast to the classical mevalonate pathway of isoprenoid biosynthesis, plants and apicomplexan protozoa such as malaria parasites have the ability to produce their isoprenoids (terpenoids) using an alternative pathway, the non-mevalonate pathway, which takes place in their plastids.

• Citric Acid Cycle

  • Unlike glycolysis, the citric acid cycle is a closed loop: the last part of the pathway regenerates the compound used in the first step.
  • This is considered an aerobic pathway because the NADH and FADH2 produced must transfer their electrons to the next pathway in the system, which will use oxygen.
  • The second form of the enzyme is found in tissues that have a high number of anabolic pathways, such as liver.
  • Several of the intermediate compounds in the citric acid cycle can be used in synthesizing non-essential amino acids; therefore, the cycle is amphibolic (both catabolic and anabolic).

• Human Metabolism

  • Catabolism is the pathway that breaks down molecules into smaller units and produces energy.
  • Anabolism is the building up of molecules from smaller units.
  • Anabolism uses up the energy produced by the catabolic break down of your food to create molecules more useful to your body.

• Biosynthesis and Energy

  • Biosynthesis is often referred to as the anabolism branch of metabolism that results in complex proteins such as vitamins.
  • A majority of the organic compounds required by microorganisms are produced via biosynthetic pathways.
  • Biosynthetic metabolism (also known as anabolism) involves the synthesis of macromolecules from specific building blocks.
  • The major pathways utilized to ensure fixation of carbon dioxide include: the Calvin cycle, the reductive TCA cycle, and the acetyl-CoA pathway.
  • In the acetyl-CoA pathway, carbon dioxide is reduced to carbon monoxide and then acetyl-CoA.

• The Pentose Phosphate Shunt

  • There are two distinct phases in the pathway: the oxidative phase and the non-oxidative phase .
  • The second phase of this pathway is the non-oxidative synthesis of 5-carbon sugars.
  • Glucose-6-phosphate dehydrogenase is the rate-controlling enzyme in this pathway.
  • While the PPP does involve oxidation of glucose, its primary role is anabolic rather than catabolic, using the energy stored in NADPH to synthesize large, complex molecules from small precursors.
  • The pentose phosphate pathway generates reducing equivalents in the form of NADPH.

• Catabolic-Anabolic Steady State

  • Anabolic reactions require energy.
  • ATP, a high energy molecule, couples anabolism by the release of free energy.
  • Anabolism is the opposite of catabolism.
  • Anabolic hormones include growth hormone, testosterone and estrogen.
  • Anabolic reactions constitute divergent processes.

• Anabolic Steroids and Muscles

  • Anabolic steroids , known technically as anabolic-androgen steroids (AAS) or colloquially as "steroids" (or even "roids"), are drugs that mimic the effects of testosterone and dihydrotestosterone in the body.
  • They increase protein synthesis within cells, which results in the buildup of cellular tissue (anabolism), especially in muscles.
  • The pharmacodynamics of anabolic steroids are unlike peptide hormones.
  • However, as fat-soluble hormones, anabolic steroids are membrane-permeable, and influence the nucleus of cells by direct action.
  • Anabolic steroids are testosterone and dihydrotestosterone hormone mimics that stimulate anabolism, specifically protein synthesis and muscle hypertrophy.

• Hormonal Regulation of Growth

  • Effects of growth hormone on the tissues of the body can generally be described as anabolic (building up).
  • Thus, GH exerts some of its effects by binding to receptors on target cells, where it activates a pathway that directly stimulates division and multiplication of chondrocytes of cartilage.
  • GH also stimulates, through another pathway, the production of insulin-like growth factor 1 (IGF-1), a hormone homologous to proinsulin.