TRANSCRIPTION Unit 4 Part I Central Dogma DNA

TRANSCRIPTION Unit 4 Part I

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 m. RNA which leaves through the nucleuar pores in the nucleus. Ribosomes then read the m. RNA to make proteins.

DNA vs. RNA DNA Deoxyribonucleic Acid Deoxyribose sugar Double stranded N bases = A, T, C, G Found in the nucleus 1 type Contains a phosphate, sugar, N base. RNA 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 � m. RNA � Carries info from DNA and delivers it to ribosome. Ribosomal RNA � r. RNA � Structural component of ribosomes Transfer RNA � t. RNA � Translates m. RNA 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 m. RNA. 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 m. RNA from the nucleus.

DNA - RNA What would the m. RNA 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