Biochemical processes

Biochemical processes

1. CATABOLIC

   • a large substrate is broken down into smaller products with the release of energy
   • exergonic: energy releasing reactions
   • digestion

2. ANABOLIC

   • smaller products are combined to form a more complex molecule with the requirement of energy
   • Endergonic: energy requiring reaction

3. ENZYMES

   • Role
     • proteins that act as catalysts
       • speed up chemical reactions in the body
     • act on substrates
     • Activation energy
       • the minimum energy which must be available to a chemical system with potential reactants to result in a chemical reaction
   • Lock and Key
     • the shape of an enzyme at the active site fits with part of the substrate molecule
     • complementary fitting of shapes
   • Active site
     • a specific region where the substrate binds
     • substrate specific
       • high specificity
       • low specificity
     • enzyme-substrate complex
       • when a substrate binds to an enzyme's active site
     • Denaturing
       • when an enzyme loses its 3D shape
       • loss of function
     • factors that affect enzyme action
       • temperature
       • pH levels
       • enzyme concentration
       • substrate concentration
       • cofactors
         • alter shape of enzymes to make active sites functional or to complete the active site
         • coenzymes, activating ions, vitamins
   • Induced fit
     • enzyme or substrate changes their shape slightly
   • Inhibitors
     • Irreversible
       • bind permanently to the enzyme
     • Reversible
       • temporarily bound to the enzyme
       • Competitive
         • competes with the substrate for the active site
       • Non-competitive
         • binds to the enzyme (not at active site) & alters its shape
         • slows down reaction rate by making the enzyme less able to perform
   • Rational drug design
     • involves the analysis of a disease to determine a structure/aspect of the disease
     • A drug is then designed to mimic/block the action of the disease causing agent
       • a drug is developed to act specifically on an infective agent/enzyme
     • Designed drug
       • designed to have specific properties

4. PHOTOSYNTHESIS

   • Light dependent
     • occurs in the grana as chlorophyll is required
     • Inputs: light, water, NADP, ADP+P
       • NADP: carrier molecule of the H+ ions
     • Outputs: oxygen, hydrogen, NADPH, ATP
     • splits H2O to obtain hydrogen
   • Light independent
     • occurs in the stroma
     • Inputs: carbon dioxide, hydrogen, ATP
     • Outputs: glucose, NADP, ADP+P
     • Calvin cycle (C3 cycle)
       • requires enzymes
       • 6 cycles of calvin cycle makes 6 carbon = 1 glucose
     • carbon fixation
     • energy required comes from ATP and carrier molecules

5. CELLULAR RESPIRATION

   • Aerobic
     • making ATP in the presence of oxygen
     • Glycolysis
       • occurs in cytosol
       • 1 glucose broken down into 2 pyruvate
       • Inputs: glucose, 2 ADP+P, 2 NAD
       • Outputs: 2 ATP, 2 pyruvate, 2 NADH
     • Link reaction
       • pyruvate is split & added to coenzyme A
     • Krebs cycle
       • occurs in the matrix (outer membrane) of mitochondria
       • Inputs: coenzyme A, 2 pyruvate, 2 ADP+P, 2 FAD, 8 NAD, 6 oxygen
       • Outputs: acetyl coenzyme A, 6 carbon dioxide, 2 ATP, 2 FADH2, 8 NADH
     • Electron transport chain
       • occurs on the cristae (inner membrane)
       • electrons from carriers are brought to the cristae
         • electrons are transported from one cytochrome to the next & are accepted by oxygen
       • Inputs: 34 ADP+P, 6 O, 8 NADH, 2 FADH2
       • Outputs: 34 ATP, 6 H2O, 8 NAD, 2 FAD
     • produces 36-38 molecules of ATP
   • Anaerobic
     • breakdown of glucose in the absence of oxygen
     • Lactate fermentation
       • occurs in animals
       • pyruvate is converted into lactate
       • lactate accumulates in muscles
     • Alcohol fermentation
       • breakdown of pyruvate to acetaldehyde
         • acetadehyde is then reduced to ethanol