C1.1 Enzymes and Metabolism

• Define catalyst 


  a catalyst is a substance that increases the rate of a chemical reaction without undergoing any permanent chemical change itself, without being consumed in the reaction itself.
• list 3 examples of anabolic processes 


  Protein synthesis, photosynthesis, DNA replication
• list 3 examples of catabolic processes 


  digestion, cellular respiration, glycolysis
• contrast and compare catabolic reactions

  anabolic is taking smaller molecules and putting them together into big molecules or bugger molecules whereas catabolic is taking larger molecules and breaking it down into several small components.
• Globular proteins properties


  globular proteins are 3-dimensional in shape, thus being soluble and to be folded into a very specific shaped protein.
• define metabolism


  metabolism refers to all the chemical reactions that occur within an organism to maintain life.
• Catalyst


  A substance that increases the rate of a chemical reaction without undergoing any permanent chemical change itself
• Enzyme


  A special type of protein-based biological catalyst that helps speed up reactions
• Role of enzymes


  • Serve as biological catalysts
  • Facilitate various chemical reactions necessary for life processes
  • Speed up reactions by lowering activation energy
• Chemical reactions


  1. Reactant(s) → Product(s)

  2. Reactant(s) get transformed into product(s)
• Substrate


  Means the same thing as reactants; a special way of saying reactant when enzymes are involved
• All bodily reactions that occur in cells would normally occur but much too slowly to sustain life
• Enzymes make it possible to have cellular reactions at a temperature that is amenable for life and a speed
• Metabolism


  Refers to all the chemical reactions that occur within an organism to maintain life
• Metabolic reactions


  • Provide energy in a multi-step process in which metabolites are oxidized
  • Can look like a variety of things
• Metabolic pathways


  • Consist of chains or cycles of enzyme-catalysed reactions
• Anabolic reactions


  Synthesis of complex macromolecules from simple molecules
• Catabolic reactions


  Breaking down large molecules into smaller components
• Anabolic reactions


  • Protein synthesis
  • Photosynthesis
  • DNA replication
• Catabolic reactions


  • Cellular respiration
  • Digestion
  • Glycolysis
• Anabolism


  • Making bonds
  • Smaller molecules to big molecules
  • Use of condensation reaction
• Catabolism


  • Breaking bonds
  • Big molecules to small molecules
  • Use of hydrolysis reaction
• Anabolic and catabolic reactions can be catalysed by enzymes
• Enzyme specificity


  The ability of enzymes to recognize and bind specific substrates
• Regulation of metabolism by enzymes

  • Control the rate and direction of metabolic pathways
  • Regulated through factors like allosteric regulation, feedback inhibition, and gene expression
• Lactase is an enzyme that helps the body digest lactose
• Polymerase is an enzyme that synthesizes long chains of polymers of nucleic acids
• Globular proteins


  Three-dimensional proteins that are soluble and folded into a specific shape
• Properties of globular proteins

  • Compact, spherical shape
  • Water-soluble
  • Often have tertiary and quaternary structures
  • Typically have specific biological functions
• Active site


  A groove or pocket of the enzyme where catalysis happens and where the substrate binds
• Induced fit model


  Active site is substrate-specific but not a fixed shape
• Enzymes and substrates undergo conformational changes to achieve optimal binding
• Induced fit model functions

  1. Substrate(s) bind to active site

  2. Active site changes shape

  3. Affects bonding in the substrate(s)

  4. Product(s) are released

  5. Active site returns to original shape
• Collision theory


  • Particles must collide
  • Must have enough energy
  • Must collide with the right orientation
• Factors affecting collision


  • Temperature
  • Concentration
  • Particle size or surface area
  • Presence of a catalyst
• Denaturation


  A permanent change to the 3D structure of the active site rendering the enzyme unable to catalyse the reaction
• Denaturation occurs when hydrogen bonds holding the structure in place are broken by heat or change in pH
• Effects of temperature and pH

  • Can denature enzymes
  • Reduce activity
  • Optimal conditions maximize enzyme activity
• Substrate concentration


  • Affects reaction rate until enzyme saturation occurs
• Hydrogen peroxide → oxygen + water