180 likes | 449 Views
RNA . 13.1 p. 362-365. 1.What does RNA stand for?. Ribonucleic acid (unlike DNA, which stands for…). 2. 3 major differences between DNA and RNA. 1. Sugar in RNA is ribose not deoxyribose 2. Single-stranded (vs. double-stranded) 3. Contains the nitrogenous base uracil vs. thymine.
E N D
RNA 13.1 p. 362-365
1.What does RNA stand for? • Ribonucleic acid (unlike DNA, which stands for…)
2. 3 major differences between DNA and RNA • 1. Sugar in RNA is ribose not deoxyribose • 2. Single-stranded (vs. double-stranded) • 3. Contains the nitrogenous base uracil vs. thymine
3. Roles of DNA vs. RNA • Kind of like a construction site • DNA is the “master plan” • Used to prepare the “blueprints” which is the RNA • DNA molecule stays safely in the cells nucleus • RNA molecules go to proteins building sites in the cytoplasm called the ribosome
4.RNA controls the assembly of amino acids into proteins! • Proteins direct/ control a lot of cellular functions…that’s one of the reasons RNA is so important!
Each of the 3 main types of RNA has a different job when it comes to protein synthesis: • Messenger RNA (mRNA) • Ribosomal RNA (rRNA) • Transfer RNA (tRNA)
5. mRNA • RNA that carries instructions for polypeptide synthesis from nucleus toribosomesin the cytoplasm!
5.rRNA • Forms an important part of both subunits of the ribosome
5.tRNA • Carries amino acids to the ribosome and then matches them to the coded mRNA message
RNA Synthesis How does the cell make RNA?
Transcription • 1.Most of the work of making RNA takes place during transcription • 2. In transcription, segments of DNA serve as templates to produce complementary RNA molecules
Where does transcription happen? • 3. Prokaryotes • RNA synthesis+ protein synthesis in the cytoplasm • 4.Eukaryotes • RNA synthesis is in cell’s nucleus • Protein synthesis is in cytoplasm
5.RNA polymerase • Works much like DNA polymerase • 6. RNA polymerase binds to DNA during transcription then separates the DNA strands • Uses one strand of DNA as a template from which to assemble nucleotides into a complementary strand of RNA
7. How does RNA know where to bind and start making RNA??? • 8.Promoter region of DNA that signals RNA polymerase exactly where to begin making RNA • *Similar signals in DNA cause transcription to stop when a new RNA molecule is completed
9-10 RNA editing • RNA needs to be edited before it can be read! • Introns= portions that are cut out and discarded • Exons= left over portions that are then pushed back together to form the final mRNA strand
Watch! • Transcription!
Photo credits • http://images.tutorvista.com/cms/images/101/rna.png • http://www.lhsc.on.ca/_images/Genetics/transcription.jpg • http://upload.wikimedia.org/wikipedia/commons/3/3e/Eukaryotic_Cell_%28animal%29.jpg • http://classes.midlandstech.edu/carterp/Courses/bio101/labquiz2/prokaryote.jpg • http://www.odec.ca/projects/2004/mcgo4s0/public_html/t3/mRNA%20to%20protein.gif