Transcription Modeling Objectives Agenda Describe and sketch the steps and products of DNA replication. Identify the difference between the structure of DNA and RNA. List the three types of RNA. Summarize the process of transcription. Quizlet Live DNA Quiz Transcription Notes Transcription Modeling Padlet

RNA Transcription & Protein Synthesis From DNA to Proteins

Protein Synthesis Overview The information in DNA is used to make proteins. These proteins are used for a variety of purposes within the body. This is called the CENTRAL DOGMA of molecular Biology

Protein Synthesis Overview However... Where is DNA located? But ribosomes are located where? How can the information get from the nucleus to the ribosomes in the cytoplasm? nucleus cytoplasm

Protein Synthesis Overview The solution is that the cell makes a temporary copy of the DNA. The temporary copy is called RNA.

Ribonucleic Acid RNA, or Ribonucleic Acid, is single stranded and made of nucleotides, just like DNA Structure of RNA nucleotide: 1. Ribose sugar 2. Phosphate 3. Nitrogen Bases Adenine (A) Guanine (G) Cytosine (C) Uracil (U): NOT Thymine (T)

Types or RNA Messenger RNA (mRNA): Acts as messenger, carries a copy of the directions from DNA to the ribosome

Types or RNA Ribosome tRNA Ribosomal RNA (rRNA): makes up the ribosome Transfer RNA (tRNA): transfers (adds) an Amino Acid to the ribosome Amino Acid tRNA Ribosome Anti-codon

RNA and Protein Synthesis DNA RNA similarities Made of Nucleotides (Phosphate, Sugar, Nitrogenous Base) Made in Nucleus A, G, C differences differences Double stranded Single stranded Only found in nucleus Can be found in nucleus or cytoplasm thymine Uracil deoxyribose Ribose Long-term Short term (temporary copy)

Transcription Transcription is the first step in protein synthesis. Purpose: make RNA, a copy of the information contained in DNA Occurs in the nucleus DNA is again unzipped, this time by RNA Polymerase. Reversibly breaks Hydrogen bonds 3 things needed to get started: DNA Free RNA Nucleotides RNA Polymerase DNA

Step 1: Initiation RNA polymerase attaches to a promoter region of DNA Draw This image RNA polymerase attaches to a promoter region of DNA Called the TATA box RNA Polymerase

Step 2: Elongation Draw This image RNA polymerase opens the DNA helix. It makes a little bubble. One strand will act as a template. RNA polymerase moves down the DNA molecule attaching complementary RNA nucleotides as it goes. Everything is the same as DNA replication except: The DNA A pairs with RNA U Template Strand Complimentary Strand

Step 3: Termination Transcription stops when RNA polymerase reaches the terminator region of DNA. Draw This image RNA Polymerase Stays in the nucleus

RNA Polymerase makes mRNA RNA Polymerase breaks H-bonds Deoxy-ribose P Thymine Cytosine Adenine Ribose P Uracil Ribose P Guanine Uracil Adenine Adenine Deoxy-ribose P Guanine Thymine ---H--- Transcription Ribose P Guanine RNA Polymerase makes mRNA Strands move apart mRNA exits nucleus RNA Polymerase breaks H-bonds DNA re-coils ---H--- Ribose P Adenine ---H--- P

Fill in the missing information

RNA Editing Many RNA molecules require a bit of editing before they leave the nucleus. mRNA: a cap and tail are added to the ends Introns- not involved in coding for proteins These get taken out in a process called splicing Exons- are expressed, used to make proteins