Cells

• In biochemistry, the different biochemical reactions associated with life will be fully understood by taking into consideration the different macromolecules in relation to the organelles of the living cell
• Cell organelles


  The different structures within a cell that carry out specific functions
• Nucleus


  • Considered as the cell's command center
  • Contains the genes: the units of hereditary material
  • Associated with nucleic acids, DNA, and RNA
• Endoplasmic reticulum


  • System of tubules and flattened sacs continuous with the nuclear membrane providing the cell with its internal support
  • May be in the form of rough ER (associated with ribosomes) or smooth ER (without ribosomes and synthesizes proteins for cell's own use)
• Ribosomes


  • Considered the cell's protein factories
  • Made up of two unequal subunits, each containing RNA
  • Sites for the synthesis of proteins
• Mitochondria


  • Largest cytoplasmic organelles and considered the cell's power plants
  • Provided with a smooth outer membrane and folded inner membrane (cristae)
  • Synthesizes and stores energy in the form of ATP
  • Self-regulating organelle that synthesizes its own proteins and is self-duplicating due to the presence of mitochondrial DNA and RNA
  • Controls concentration of water, calcium, and other ions in the cytoplasm; breakdown and recycling of sugars, fatty acids, and amino acids
• Golgi apparatus


  • Flat, membranous sacs, vesicles, and vacuoles considered as packagers of cell's proteins
  • Responsible for concentrating and wrapping certain enzymes into separate organelles which remain inside the cell
• Lysosomes


  • Considered as the scavengers of the cell
  • Referred to as bags of enzymes, suicide bags, or graveyard of the cell
  • Principal site of intracellular digestion
• Microtubules and microfilaments


  • Not membrane-bound
  • For transport of materials, cell movement, and cell support
• Cell membrane


  • Considered as the cell's delicate but tough "guardian"
  • Composed of lipids, proteins, and oligosaccharides
  • Regulates the translocation of materials
• Cell macromolecules


  • Nucleic acid
  • Proteins
  • Lipids
  • Carbohydrates
• The cell (protoplasm) is a combination of true and a colloidal solution since some of its components are insoluble while others are soluble in its water medium
• Colloidal properties of the cell

  • Filterability
  • Negligible osmotic pressure
  • Tyndall phenomenon
  • Brownian movement
  • Electrical charges
  • Surface tension
  • Osmosis
  • Diffusion
  • Dialysis
• Water


  • An essential substance for plant and animal growth
  • Makes up 70-90% of the cell's weight and is an inert space filler in living organisms
  • Due to its highly reactive and unusual properties and its ionization products H+ and OH-, water is an important factor in modifying structures of biomolecules
• General properties of water

  • Chemically pure water is colorless, odorless and tasteless
  • Has a higher boiling point and osmotic pressure
  • High specific heat
  • High latent heat of vaporization
  • High surface tension
  • Had the capacity to dissipate heat to its environment
• Biological importance of water

  • Universal solvent
  • An electron dipole
  • Altered by solutes
  • Water molecule has a tendency to dissociate
• pH scale


  Ranges from 0 (highly acidic) to 14 (highly basic), with 7 being neutral
• Physiological buffer system


  • A system that can resist a change in pH upon the addition of either acid or base
  • Solutions of weak acids and their conjugate bases and on weak bases and their conjugate acids exhibit buffering
  • Functional groups such as carboxyl group, amino group and phosphate esters are functional groups of are weak acids or bases that many biomolecules possess
• Inorganic ions are vital to the normal functioning of some enzymes and for the maintenance of functional conformation of proteins, nucleic acids, and carbohydrates
• What are lysosomes?


  Organelles found within a cell
• What is another name for lysosomes?

  Bag of enzymes
• What's another name for lysosomes, and what does it refer to?


  Suicide bags, referring to the ability of lysosomes to engulf and digest their own cell's components
• What else can lysosomes do?

  They can also recycle or dispose of damaged or dysfunctional cellular components, effectively "burying" them
• What's the primary location in the cell where cellular waste and debris are broken down and recycled?


  Principal site of intracellular digestion, which is in lysosomes
• CELL • Biochemistry explores molecular mechanisms of normal cellular processes as well as diseases.