lesson 2

• Atom


  • Smallest component of an element
  • Contains protons, electrons and neutrons
• Protons


  • Positively charged
  • Particles that reside inside the nucleus (core of the atom)
• Electrons


  • Negatively charged
  • Particle that travel in the space around the nucleus (outside the nucleus)
• Neutrons


  • No charge
  • Can be found inside the nucleus
• Molecules


  The results of the reaction between two or more atoms of the same element or with atoms of other elements
• Chemical bonding


  Interactions involving atoms of elements combining with one another
• Covalent bond


  Electrons are shared
• Ionic bond


  Electrons are transferred from one atom to another
• Hydrogen bond


  Hydrogen combines with oxygen or with another electromagnetic atom
• Organic molecules


  • Always contain carbon and hydrogen
  • Atoms are held together by covalent bond
  • Associated with living organisms
• Carbohydrates


  • Composed of carbon, hydrogen, and oxygen in definite ratio (1:2:1)
  • With general formula of CH2O
  • The main source of energy in the body
• Types of carbohydrates


  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Monosaccharides


  • Simple sugar
  • Important source of cell energy
• Disaccharides


  • Double sugar
  • Two monosaccharides bonded together
  • Principle sugar transported throughout bodies of plants
• Polysaccharides


  • Complex sugar
  • Many monosaccharides bonded together
• Lipids


  • Composed of carbon, hydrogen, and oxygen with no definite ratio
  • The number of oxygen atoms is very much less compared to hydrogen atoms
  • Storage of energy and important component of the cell membrane
• Types of lipids

  • Simple lipids
  • Compound lipids
  • Steroids
• Simple lipids

  • Triglycerides
  • Composed of three fatty acids bonded to glycerol
• Compound lipids


  Composed of lipids in combination with other compounds
• Steroids


  Composed of four fused rings of carbon atoms with functional groups attached
• Proteins


  Composed of carbon, hydrogen, oxygen and nitrogen plus other elements such as sulfur, iron, iodine, etc.
• Types of proteins

  • Fibrous protein
  • Globular protein
  • Conjugated proteins
• Fibrous protein


  • Polypeptides are arranged parallel along a single axis to produce long fibers or sheets
  • Examples: collagen, keratin, fibrinogen, muscle proteins, silk
• Globular protein


  • Polypeptides are so tightly folded into spherical or globular shapes
  • Examples: albumins, globulins, hemoglobin, enzymes, antibodies, hormones
• Conjugated proteins


  • Simple proteins in union with other substances
  • Examples: nucleoprotein, glycoprotein, lipoprotein, chomoprotein
• Nucleic acids


  • Composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus
  • Important in protein synthesis as RNA and in heredity as DNA
• Biochemical reactions


  • Chemical reactions that take place inside the cells of living things
  • The sum of all biochemical reactions in an organism, called metabolism
• Inorganic molecules


  • Contains positive and negative ions
  • Atoms are held tighter by ionic bond
  • Associated with non living things
• Water


  • The most abundant company of the protoplasm
  • Composed of two atom of hydrogen and an atom and an atom of oxygen
  • H2O
• Salts


  • Formed from neutralization of an acid and a base
  • Important in vital processes such as irritability of muscled and nerves, growth and repair of tissues, etc.
• Gases


  Important in oxidation of food molecule in order to release energy
• Acids


  Molecules that raise the hydrogen ion concentration when added to a solution
• Bases


  Molecules that lower the hydrogen ion concentration when added to a solution