Biology

• DNA contains genetic information that controls how cells function.
• DNA (deoxyribonucleic acid) is the genetic material
• DNA stores information
• DNA is the basis of inheritance
• DNA distinguishes living things from nonliving things
• Genes


  Various units that govern living thing's characteristics at the genetic level
• Nucleotides


  Genes contain information as a specific sequence of nucleotides found in DNA molecules
• Nitrogenous bases in DNA

  • Guanine
  • Adenine
  • Thymine
  • Cytosine
• Nucleotide


  A sugar group attached to a phosphate group and a nitrogenous base
• Complicated genes can be many thousands of nucleotides long
• An organism's genetic instructions, its genome, can be maintained in millions or even billions of nucleotides
• 5' end


  The end of a string of nucleotides with a carbon not attached to another nucleotide
• 3' end


  The other end of the molecule with an unattached carbon
• Base pairing


  G paired with C, A paired with T
• The information content on one DNA strand is essentially redundant with the information on the other
• The strands are not exactly the same but are complementary
• Upstream


  Sequence features that are 5' to a particular reference point
• Downstream


  Sequence features that are 3' to a particular reference point
• Different kinds of organisms have different numbers of chromosomes
• Humans have 23 pairs of chromosomes
• Central Dogma of Molecular Biology

  DNA information -> RNA -> Protein
• Protein


  Functional unit, such as an enzyme
• Gene


  Instructions needed to make a protein
• Central Dogma


  1. DNA -> Transcription -> RNA

  2. RNA -> Translation -> Protein
• Complementary DNA (cDNA)


  DNA obtained from reverse transcription
• RNA (ribonucleic acid)


  Single-stranded polynucleotide with bases A, G, C, U (uracil) instead of T
• Transcription (DNA -> RNA)


  DNA, GCG, CGC, TGT -> RNA
• Messenger RNA (mRNA)


  Carries information to be translated
• Ribosomal RNA (rRNA)


  The working "spine" of the ribosome
• Transfer RNA (tRNA)


  The "decoder, keys" that will translate nucleic acids to amino acids
• Protein


  Sequence of amino acids connected by peptide bonds
• Peptide


  30-50 amino acids
• Protein


  Longer peptide
• Gene expression


  Using the information in DNA to make an RNA molecule and then a corresponding protein