DNA Structure and Function

• DNA contains the genetic information that codes for the RNA and proteins necessary for cell function.
  
  
• All DNA in the chromosomes has to be copied (replicated) and transmitted to daughter cells via mitosis.
  
  
• Non-faithful replication or inability to correct errors and damage to DNA results in mutations.

Structure of DNA

• Four nucleotides (A,T,C,G) are chemically joined through sugar and phosphate molecules in the backbone.
  
  
• Base pairs across the double helix are joined by complementary base-pairing: A base pairs with T, C base pairs with G. The complementary base pairs direct the addition of nucleotides during synthesis of new DNA strands or synthesis of mRNA (where U is used instead of T) or hybridization of two different molecules.
  
  
• The overall directionality (seen best by looking at the sugar molecules) is antiparallel in the two strands. One strand has a 5'-3' direction; the other a 3'-5' direction. This has consequences for enzymes that work on the DNA (e.g. DNA polymerase, restriction enzymes).

	DNA Structure and Function
	DNA Replication
	Transcription
	Transcription Factors
	Signal Transduction
	Cell Cycle