BIOCHEM LEC 1ST QUARTER

• Chemical reactions in cells:

  • Oxidation: increase in oxidation number, addition of oxygen, removal of hydrogen
  • Reduction: decrease in oxidation number, addition of hydrogen, removal of oxygen
  • Hydrolysis: reaction in the presence of water, acid, base, or enzyme
  • Tautomerism: interconversion of aldehyde/ketone to alcohol
  • Condensation: reaction of two or more substances with the removal of water from the molecules
• pH and Buffer Computation:

  • pH = -log [H+]
  • pOH = -log [OH-]
  • [H+] = inv. log – pH
  • [OH-] = inv. log – pOH
  • pH = pKw – pOH
  • pOH = pKw – pH
  • pH = 14 – pOH
  • pOH = 14 – pH
  • [H + ] = Kw/[OH - ]
  • [OH - ] = Kw/[H + ]
  • [H + ] = 1 x 10 -14/ [OH - ]
  • [OH - ] = 1x10 -14 /[H + ]
  • Henderson-Hasselbalch Equation: pH = pKa + log A-/HA
• Dissociation of Water:

  • Equilibrium constant expression: Kw = [H3O+][OH-]
  • Kw is a constant, 1.0 x 10 − 14, for all aqueous solutions at 25 o C
  • To calculate [ − OH] when [H3O + ] is known: Kw = [H3O + ][ − OH]
  • To calculate [H3O + ] when [ − OH] is known
• The pH Scale:

  • General formula: pH = − log [H3O + ]
  • The lower the pH, the higher the concentration of H3O+
  • Acidic solution: pH < 7 -> [H3O + ] > 1 x 10 − 7
  • Neutral solution: pH = 7 -> [H3O + ] = 1 x 10 − 7
  • Basic solution: pH > 7 -> [H3O + ] < 1 x 10 − 7
• Focus in the Human Body: The pH of Body Fluids:

  • Saliva = pH 5.8 – 7.1
  • Blood = pH 7.4
  • Pancreas = pH 7.5 – 8.8
  • Small intestine = pH 8.5
  • Stomach = pH 1.6 – 1.8
  • Large intestine = pH 5.0 – 7.0
  • Urine = pH 4.6 - 8.0
• Biochemistry is sometimes called biological chemistry
• It is the study of the components and composition of living things and how they come together to become life
• Biochemistry is related to molecular biology, concerning genetic information encoded in DNA and understanding the structures, functions, and interactions of biological macromolecules
• Biochemistry is a branch of science exploring the chemical processes within and related to living organisms
• It brings together biology and chemistry to understand and solve biological problems
• Biochemistry focuses on processes happening at a molecular level to understand how the structure of a molecule relates to its function and how molecules will interact
• Biochemistry includes the study of components like proteins, lipids, carbohydrates, nucleic acids, and organelles
• Biochemistry describes all the complex interrelated chemical changes within the cell called metabolism
• Intermediary metabolism is intimately related to the processes of growth, reproduction, and heredity
• Biochemistry involves the study of chemical substances and processes that occur in plants, animals, and microorganisms
• Metabolism describes all the chemical changes within organisms, including the degradation, building up of complex molecules, and gaining energy necessary for life processes
• Enzymes are organic catalysts that act on these chemical changes and their existence depends on the genetic apparatus of the cell
• Biochemistry is important in medicine, helping to understand how microorganisms operate and the effects of medication on the body
• In agriculture, biochemistry can help develop pesticides that kill weeds and insects without causing excessive damage to crops
• Biochemistry covers a range of scientific disciplines including genetics, microbiology, forensics, plant science, and medicine
• Biochemical studies have shed light on many aspects of health and disease, contributing to cell biology, physiology, immunology, microbiology, pharmacology, and toxicology
• Biochemistry is essential to all life sciences and is the basis for understanding health and diseases
• Biochemistry is applied to medicine, dentistry, veterinary medicine, pharmacology, physiology, microbiology, and clinical chemistry
• Biochemists research ways to develop abundant and inexpensive sources of nutritious foods, determine the chemical composition of foods, and invent ways to prolong the shelf life of food products
• Biochemists in agriculture study the interaction of herbicides with plants, examine the structure-activity relationships of compounds, and evaluate their toxicological effects on surrounding life
• Toxicology deals with toxic metabolites in the body and involves understanding how organic compounds are changed by enzymes into toxic metabolites
• Major causes of diseases include physical agents, chemical agents (including drugs), biologic agents, oxygen lack, genetic disorders, immunologic reactions, nutritional imbalances, and endocrine imbalances
• Rogene Henderson focuses on determining the health effects of inhaled pollutants and develops chemical analytical techniques
• Carbohydrates are polyhydroxy aldehydes or ketones, or compounds that can be hydrolyzed to them
• Carbohydrates are synthesized in green plants by photosynthesis, storing energy from the sun as chemical energy in carbohydrates
• In the body, carbohydrates are used for bursts of energy needed during exercise in the form of glucose
• Sources of carbohydrates in foods include all sugars: sucrose, glucose, fructose, lactose, maltose, and starches found in pasta, bread, and grains
• Carbohydrates that the human body doesn't digest include insoluble fiber like cellulose from plants and chitin from insects and other arthropods
• Carbohydrates have six major functions in the body:

  • Providing energy
  • Regulating blood glucose
  • Sparing the use of proteins for energy
  • Breaking down fatty acids
  • Providing dietary fiber
  • Acting as a natural sweetener for foods
• Glucose energy is stored as glycogen, with the majority of it in the muscle and liver
• Properties of water:

  • Water is the most abundant molecule in cells, accounting for 70% or more of total cell mass
  • It is a polar molecule with hydrogen atoms having a slight positive charge and oxygen with a slight negative charge
  • Water molecules can form hydrogen bonds with each other or with other polar molecules, as well as interact with positively or negatively charged ions
  • Hydrophilic substances are readily soluble in water, while hydrophobic substances are poorly soluble
• The primary role of carbohydrates is to supply energy to all cells in the body
• • Water plays multiple roles in living organisms such as being a solvent, temperature buffer, metabolite, and living environment
  • It acts as a solvent for many chemical reactions and helps transport dissolved compounds into and out of cells
  • Water is a metabolite in various chemical reactions like photosynthesis, digestion, and aerobic respiration
  • Water interacts with solvated biomolecules influencing their structure and can become a reactant or product in metabolic reactions as an excellent nucleophile
• Regulation of water balance:

  • Depends on hypothalamic mechanisms controlling thirst, antidiuretic hormone (ADH), retention or excretion of water by the kidneys, and evaporative loss
  • Nephrogenic diabetes insipidus results from the unresponsiveness of renal tubular osmoreceptors to ADH
• Monosaccharides are the simplest carbohydrates, generally having 3 to 6 carbon atoms in a chain with an aldehyde or ketone ending and many hydroxyl groups