BMS 300 1st Edition Lecture 9 Outline of Last Lecture I. Phospholipid orientation in water -micelle -liposome -planar bilayer II. Lipid mosaic model of biological membrane -transmembrane proteinsIII. Proteins as amino acid polymers -amino acid structure 1. amine 2. carboxylic acid 3. R-group -peptide bond formation IV. Protein primary structure -amino acid sequence V. Protein secondary structure -hydrogen bonding>alpha helix>beta sheet These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Outline of Current Lecture I. RNA and its transcription from DNA -RNA types 1. mRNA2. tRNA3. rRNA4. regulatory -RNA structure 1. 5-carbon sugars (ribose) 2. phosphodiester bonds 3. bases:-purines >adenine>guanine-pyrimidines >cytosine >uracil II. RNA polymerase and transcription initiation III. Promoter (where you start) -TATA box IV. Transcription factor-DNA binding protein—to promoter -recruitment of RNA polymeraseV. Transcription of RNA from DNA -read DNA 3’ to 5’ -generate RNA 5’ to 3’VI. RNA editing -cut out introns -leave extrons-edit RNA in nucleus VII. RNA to cytoplasm leave exons -translation -RNA’s working together Current LectureRNA structure-the structure is important because the #3 can link to the #5 carbon etc. -you can link the two structures and they form a phosphodiester bond in the middle -you can then repeat this pattern over and over just like DNA -all of the #1 can have one of four bases attached: adenine, guanine, cytosol, and uracil-all of the #2 carbons will be a hydroxyl because of the ribose -the uracil and the thymine are related structures -thymine is found in DNA and uracil is found in RNA—which allows for more flexibility in the structure -the only difference is uracil has an H and thymine has a H3C -adenine pairs with thymine in DNA and pairs with uracil in RNA -because of the hydroxyl at the bottom of this structure we are not required to make another strand for the RNA to bind to*RNA is a single stranded molecule -it can fold back on itself instead of only being one giant strand -by having only 4 bases there is a limited amount of geometric shapes that can form but it can still form some -the riboses are linked by phosphodiester bondsRNA polymerase-catalyzes phosphodiester bondsTranscription-transferring information from DNA to RNA -DNA provides the molecule where information is stored and then we can create a molecule that will do the work in RNA -there is a promoter in the middle of a DNA strand- TATA box -the TATA box needs to work in concert with a DNA binding protein called a transcription factor-the transcription factor comes in, finds the promoter region, and binds a protein*there is information in the DNA that provides sources where a protein can bind -a molecule of RNA polymerase comes in and begins reading a DNA strand-the RNA polymerase reads DNA 3’ to 5’ which means it generates RNA 5’ to 3’*long stretch of DNA, use a subset of the DNA called a TATA box, then the RNA polymerase comes in and settles around it, and one of the jobs of RNA polymerase plays the role of breakingthe hydrogen bonds -this creates a RNA molecule that’s complimentary to the RNA strand -we use the information in the DNA to create a RNA strand -we continue to do this until we come to an end “signal”-we then have generated a RNA transcript in the nucleus **see image belowRNA editing (splicing)-all three forms of these RNA (tRNA, mRNA, and rRNA)—rRNA is the one that gets mostly edited -recognize that the sequence is exactly complimentary to the DNA strand-we cut and splice the RNA transcript which is known as the editing -goes down and “cuts” the RNA -the number 1 section will be cut away from the strand and so on-we have then edited the RNA transcript and the intervening sequences (introns) have been discarded and tied back the exons Introns: interveningExons: expressed -while still in the nucleus we took the complimentary strands of RNA and cut them into new strands -we can cut the RNA in slightly different places and when they are put back together then we can make slight changes to the amino acids aka slight changes to the different genes**all of this is confined to the
View Full Document
Unlocking...