DNA

Nucleic Acids

Roles in the storage, transmission and expression of genetic material

DNA - deoxyribose + a phosphate group + a nitrogen containing base (purine and pyridamine)

RNA - ribose + a phosphate group + a nitrogen containing base (purine and pyridamine)

DNA - deoxyribose + a phosphate group + a nitrogen containing base (purine and pyridamine)

Pyridamines - cytosine (c) and thymine (t)

purines - guanine (g) and adenosine (a)A=TC=G

Replication

Synaptic phase of interphaseDNA “unzips”each side acts as a template to

complete a new strand of DNAeach replicated stand consists of one

new strand and one old strand - semiconservative replication

Replication

…is never 100% accuratealways some variationHow does error occur?Errors in somatic cellsErrors in gametes

RNA

While DNA contains the genetic message it does not actually contain the information to cause the message to be expressed

RNA is the messengerRNA synthesis similar to DNA

Transcription

DNA “unzips”RNA is synthesized using the DNA as

a template except that thymine is replaced by uracil (A=U)

RNA detaches (single strand)DNA reconnects as transcription is

completed

3 types of RNA

Messenger RNA (RNAm) carries coded instructions for protein synthesis

Transfer RNA (RNAt) carries specific amino acids to ribosomes during protein assembly

Ribosomal RNA (RNAr) part of ribosomes