Feb Dr. Pandya is not here… how do we learn day? Watch the clips. Take notes, rewind them and listen carefully! We are making proteins today! Get all the details!!! PS. If you have time go back and review the RNAi video (Nova science now)
HHMi Transcription Basic Detail Define what the following terms do: Promotor: RNA Polymerase: Activator Proteins: Enhancer regions: What was the Central Dogma of biology mentioned?
What are the three stages of transcription? Initiation: RNA polymerase binds to the DNA promoter. Fig 17.8 – TATA box is the area that transcription factors recognize within the promoter. – Creates a transcription initiation complex (transcription factors & RNA polymerase bond on promoter) Elongation: DNA template continues to grow as RNA polymerase separates DNA strand. – Transcribed part: Transcription unit (made of codons) (1 gene transcribed many times in caravan fashion) Termination: mRNA is cut free from DNA template
Tata Box Explained Transcription in Detail Watch the clip. Go to the quiz. Write down the question and correct answer. If you picked the wrong choice initially please write an extra sentence correcting it.
How do Eukaryotes control Gene expression? Transcription creates Pre-mRNA. Fig Pre-mRNA includes Introns and Exons Introns= Fillers (intervening sequences) Exons= Code for proteins (expressed sequences) mRNA is just the Exons Eukaryotic Transcription
How else is mRNA processed for translation? Background Info snRNP’s (“snurps”) & splicesomes remove introns, creating the final mRNA sequence= Exons only. Fig What stops the mRNA from degrading by hydrolytic enzymes & binds it to the ribosome? – 5’ cap: modified guanine nucleotide is added to the 5’ end. – A poly tail: adenine nucleotides on the 3’ end. (Also helps release mRNA into the cytoplasm. Enhancer’s causes the gene it is enhancing to be expressed. Transcription occurs in eukaryotes when an enhancer site is activated.
snRNP’s Splicesomes Caps And Tails Take notes on: What is an Intron What is an Exon What is an 5’ cap What is an 3’ poly A tail What are a snurps? What is a spliceosome. What is gene splicing? What is Exon Shuffling. How is it important to evolution? Where does it all go? This one First This one Second Take notes on: What happens when it leaves the nucleus.
Reminder and Review…yes you saw this before…. But its not the same!!!! Initiation: mRNA’s AUG codon (methionine) attaches to the ribosome. tRNA attaches. Elongation: forms the polypeptide chain as tRNA’s continue to attach. Termination: mRNA reaches a stop codon. Release factor hydrolyzes the bond. mRNA is degraded. Polypeptide is freed from ribosome. – After this the polypeptide will fold or pleat (secondary structure), Chaperonine will complete the tertiary structure. What process was this for???? Translation
What about when a mistake occurs? They can effect the species gene pool. Point mutation= single base-pair substitution. (sickle cell) Insertion or deletion= frameshift mutations. The Dog -> HeD og Missence Mutation= If a codon within a gene turns into a stop codon translation is altered. Transcription full on with all the details!!!! Last set of questions: What is the P site What is the A site? What is the E site? How does the ribosome know were to begin and end translation. Why is this called translation?
That’s it. You’ve done it. CONGRADULATIONS and THANK YOU!!!