Transcription Unit 4 Part I

DNARNA Proteins Traits Central Dogma DNARNA Proteins Traits This is the central dogma (theme) of molecular genetics. These are the steps needed to get from a DNA double helix to the traits you posses.

Central Dogma How do you get from DNA to RNA to Proteins to Traits? Amino Acids DNA  RNA  PROTEINS  TRAITS TRANSCRIPTION TRANSLATION control

Review DNA – only found in the nucleus Ribosomes (protein factories) – in the cytoplasm Hoes does DNA get information needed to make proteins from the nucleus to the ribosome? DNA makes mRNA which leaves through the nucleuar pores in the nucleus. Ribosomes then read the mRNA to make proteins.

DNA vs. RNA Deoxyribonucleic Acid Deoxyribose sugar Double stranded N bases = A,T,C,G Found in the nucleus 1 type Contains a phosphate, sugar, N base. Ribonucleic Acid Ribose sugar Single stranded N bases = A,U,C,G Uracil replaces Thymine Found in the nucleus and cytoplasm 3 types Contains a phosphate, sugar, N base.

DNA vs. RNA DNA RNA

Types of RNA Messenger RNA mRNA Carries info from DNA and delivers it to ribosome. Ribosomal RNA rRNA Structural component of ribosomes Transfer RNA tRNA Translates mRNA sequences into amino acid sequences

Transcription Steps: 1. RNA Polymerase – binds to DNA and signals to start making RNA, then unwinds/splits DNA into 2 separate strands. 2. One strand – of DNA acts as a template for making mRNA. 3. RNA Polymerase – moves along the DNA and pairs each base with a complementary RNA nucleotide 4. Continues – until enzyme reaches a terminator (stop signal). 5. RNA Polymerase – detaches from DNA and releases mRNA from the nucleus.

DNA - RNA ATC CAG TCA GAT CTA CCG What would the mRNA strand be if the DNA template is: (remember that A now pairs with U and C still pairs with G) ATC CAG TCA GAT CTA CCG