Introduction to Biochemistry

• Biochemistry is the systematic study of the chemicals of the living systems, their organization, and the principles of their participation in the processes of life
• Molecules are lifeless, yet they compose living things
• Living systems


  • They can grow, move, perform the incredible chemistry of metabolism, respond to stimuli from the environment, and most significantly, replicate themselves with exceptional fidelity
• Chemistry is the logic of biological phenomena and responsible for the characteristics of life
• The major objective of biochemistry is the complete understanding, at the molecular level, of all of the chemical processes associated with living cells
• Life sciences that require knowledge of biochemistry

  • Genetics
  • Physiology
  • Immunology
  • Pharmacology
  • Toxicology
  • Pathology
  • Microbiology
  • Zoology
  • Botany
• Knowledge of biochemical molecules

  Clarifies our understanding of diseases
• Life is based on compounds of carbon, and biomolecules are part of the subject matter of organic chemistry
• Any compound that occurs in a living organism can be synthesized in the laboratory, although in many cases the synthesis represents a considerable challenge
• The reactions of biomolecules can be described by the methods of organic chemistry, which requires the classification of compounds according to their functional groups
• Many functional groups in biomolecules contain oxygen and nitrogen, which are among the most electronegative elements, and their polar nature plays a crucial role in their reactivity
• Esters and anhydrides of phosphoric acid are of vital importance in biochemistry, such as in the energy currency of the cell, adenosine triphosphate (ATP)

  
• Four major types of biomolecules

  • Carbohydrates
  • Lipids
  • Nucleic acids
  • Proteins

  
• Nucleic acids


  They have the unique function of storing an organism's genetic code - the sequence of nucleotides that determines the amino acid sequence of proteins, which are of critical importance to life on Earth
• Proteins


  They are major structural elements of cells, serve as transporters, act as enzymes and catalysts for chemical reactions, form antibodies and hormones, and influence gene activity
• Carbohydrates


  They are essential energy sources and structural components of all life, and they are among the most abundant biomolecules on Earth. They are built from four types of sugar units - monosaccharides, disaccharides, oligosaccharides, and polysaccharides
• Lipids


  They fulfill a variety of roles, including serving as a source of stored energy, acting as chemical messengers, and forming membranes that separate cells from their environments and compartmentalize the cell interior

  
• Cells have three basic needs: materials, information, and energy
• Parts of the cell

  • Cell membrane/plasma membrane
  • Nucleus
  • Cytoplasm
  • Mitochondria
  • Endoplasmic reticulum
  • Ribosomes
  • Golgi apparatus
  • Lysosomes
  • Peroxisomes
• Cell membrane/plasma membrane


  A semi-permeable membrane surrounding the cell that separates its internal environment from the external environment; permits and/or enhances the absorption of essential nutrients into the cell while preventing the diffusion of needed metabolites
• Nucleus


  The "information center" that contains the cell's genetic information and is the site of DNA and RNA synthesis
• Cytoplasm


  The aqueous phase where the mitochondria, ribosomes, and other organelles are suspended
• Mitochondria


  The "power house" of the cell where carbohydrates, lipids, and amino acids are oxidized to CO2 and H2O by molecular O2 and provides energy for ATP synthesis
• Endoplasmic reticulum (ER)


  Contains two types - rough ER (involved in synthesis of membrane proteins and protein for export from the cell) and smooth ER (synthesis of steroids, phospholipids, and complex polysaccharides)
• Ribosomes


  The "workbench of protein synthesis" where translation occurs
• Golgi apparatus


  The organelles to which synthesized proteins are transported and temporarily stored before release from the cell, serving as "packaging stations"
• Lysosomes


  The "suicide bag" of the cell that function in the digestion of materials brought into the cell and the digestion of cell components after cell death
• Peroxisomes


  Contain oxidative enzymes that oxidize amino acids, uric acid, and various 2-hydroxyamino acids using O2 with formation of H2O2, which is then converted to H2O and O2
• Differences between prokaryotic and eukaryotic cells

  • Prokaryotes are single-celled organisms without a well-defined nucleus
  • Eukaryotes contain a well-defined nucleus surrounded by a nuclear membrane
• Differences between animal and plant cells

  • Plant cells have cell walls, chloroplasts, and vacuoles, which animal cells do not have