Metabolism

• Molecules


  • Proteins
  • Carbohydrates
  • Fats
  • Lipids
• All living things carry out a large number of different chemical reactions
• These reactions are catalyzed by enzymes
• Most of them happen in the cytoplasm of cells but some are extracellular such as the reactions used to digest food in the small intestine
• Metabolism


  The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways; which manage the material and energy sources of the organism
• Metabolism


  • Is an emergent property of life that arises from interactions between molecules within the orderly environment of the cell
  • The organization of the chemistry of life is in metabolic pathways (begins with specific molecules, which is then altered in a series of defined steps, resulting in a certain product)
• Metabolic pathways


  • Glycolysis
  • Citric acid cycle
  • Electron transport chain
• Even in relatively simple prokaryotic cells, metabolism consist of over 1,000 different reactions
• Each step of the pathway is catalyzed by a specific enzyme
• Pathways can have more than one starting molecule and/or product
• Metabolic pathway


  1. Starting molecule

  2. Enzyme catalysis

  3. Reaction 1

  4. Reaction 2

  5. Reaction 3

  6. Reaction 4

  7. Reaction 5
• Catabolism


  Metabolic pathways that release energy by breaking down complex molecules to simpler molecules
• Anabolism


  Metabolic pathways that consume energy to build complicated molecules from simpler ones
• Energy is fundamental to all metabolic processes
• Catabolic reactions release energy by breaking down complex molecules to simpler molecules
• Anabolic reactions consume energy to build complicated molecules from simpler ones
• Catabolic processes


  • Digestion of food in the mouth, stomach and small intestine
  • Cell respiration in which glucose or lipids are oxidized to carbon dioxide and water
  • Digestion of complex carbon compounds in dead organic matter by decomposers
• Anabolic processes


  • Protein synthesis using hormones
  • DNA synthesis during replication
  • Photosynthesis, including production of glucose from carbon dioxide and water
  • Synthesis of complex carbohydrates including starch, cellulose and glycogen
• Anabolic reactions build larger molecules from simpler ones using energy.
• Catabolic reactions break down molecules into smaller units to release energy.
• Catabolic reactions break down large molecules into smaller ones releasing energy.
• The process of photosynthesis is an example of both catabolic and anabolic reactions occurring simultaneously.
• In photosynthesis, chlorophyll absorbs light energy and uses it to convert CO2 and H2O into O2 and C6H12O6 (glucose). This is an example of an anabolic reaction as it builds up large molecules from simple ones.
• At the same time, ATP is produced through photolysis, where light energy is used to split water molecules into oxygen and hydrogen atoms. The hydrogen then combines with ADP to form ATP, releasing energy that can be used for other metabolic activities. This is an example of a catabolic reaction as it breaks down molecules to release energy.
• The process of breaking down large molecules into smaller ones is called catabolism.
• The process of building up large molecules from smaller ones is called anabolism.
• At the same time, ATP is produced by breaking down ADP and Pi through phosphorylation. This is an example of a catabolic reaction as it breaks down molecules to release energy.
• Respiration is the opposite of photosynthesis and involves breaking down glucose to produce carbon dioxide, water, and energy.
• Anabolism refers to building larger molecules out of simpler ones using energy released by catabolism.
• Metabolism involves two types of chemical reactions - catabolism and anabolism.
• Metabolism refers to all chemical processes taking place within living organisms.
• Catabolism involves breaking down complex organic compounds into simpler substances, releasing energy in endergonic reactions.
• Anabolism involves synthesizing complex organic compounds from simpler substances using energy released by exergonic reactions.
• Catabolism is the breakdown of complex organic compounds (food) into simple substances that can be used or stored by cells.
• Examples of catabolism include digestion of food in the stomach and small intestine, respiration in mitochondria, and hydrolysis of glycogen in liver cells.
• Examples of catabolic reactions include respiration (breaking down glucose) and digestion (breakdown of food).