DNA Replication Review Five main steps: Helicase unzips/unwinds the DNA molecule SSB proteins hold unwound DNA in place Primase add RNA primers so DNA Polymerase knows where to start DNA Polymerase adds new nucleotides Ligase glues the new DNA back together Why is DNA Replication important? The important idea is that an exact duplication of the DNA message is required, so that each new cell in the body has the same set of genetic instructions as the cells that preceded it. This also insures that every new generation of individuals has the same genetic information as his/her parents.

DNA carries information used to make proteins which form structures and regulate the body’s activities. Write Protein synthesis involves two processes: transcription and translation. Transcription: DNA message is converted into an RNA molecule. Translation: RNA message is used to assemble amino acids into a protein chain.

Central Dogma: Location Write/Draw

Central Dogma Write/Draw

First, let’s learn about RNA Write RNA is also a nucleic acid, called ribonucleic acid Has one strand (DNA has two) It contains the sugar ribose instead of deoxyribose It has the nitrogenous base URACIL (U) instead of thymine (T)

T-P-S Compare

There are THREE type of RNA Write There are THREE type of RNA Messenger RNA (mRNA) formed in nucleus and complementary to one strand of DNA Ribosomal RNA (rRNA) Forms ribosomes in the cytoplasm Transfer RNA (tRNA) Transport amino acids to the ribosome where proteins are made by adding 1 amino acid at a time

Messenger, ribosomal, transfer RNA

TRANSCRIPTION (first step in protein synthesis) Write TRANSCRIPTION (first step in protein synthesis) DNA code is transferred to mRNA in the nucleus. DNA is unzipped in the nucleus and RNA polymerase binds to a specific section where a mRNA will be made

Transcription does not happen all the time Observe Transcription does not happen all the time Operon – the “switch” to turn on/off transcription Promoter – DNA site that promotes RNA polymerase to bind Repressor – molecule that binds to DNA to block transcription Inducer – molecule that takes repressor away

Recap Translation