MIT Biology Departme 7.012: Introductory Biology-Fall 2004 Instructors: Professor Eric Lander, Professor Robert A Weinberg, Dr. Claudette Gardel Solutions to 7.012 Problem set 4 Question 1 Below is an electron micrograph of a single gene being transcribed. The DNA strand runs horizontally with RNa transcripts extending vertically outward Image removed due to copyright reasons a)Draw an arrow indicating the direction that the RNA polymerases are transcribing. Why did you choose this direction? The mRNA molecules near the right side are short whereas the mRNA molecules towards the left are longer. The longer mRNA molecules will be towards the end of the gene Which strand is the template strand, the top or the bottom strand? Explain your choiceove b)Below is a partial sequence of the above gene. Its orientation is the same as pictured ACTCGATGCTAG STGAGCTACGATC mRNA is only made 523, so the top strand will be the template strand in the direction c)What would be the mRNa sequence transcribed from the above sequence? Be sure to label the5′and3′ends 5′ CUAGCAUCGAG3 7012Fall2003MIT Biology Department 7.012: Introductory Biology - Fall 2004 Instructors: Professor Eric Lander, Professor Robert A. Weinberg, Dr. Claudette Gardel Solutions to 7.012 Problem Set 4 Question 1 Below is an electron micrograph of a single gene being transcribed. The DNA strand runs horizontally with RNA transcripts extending vertically outward. Image removed due to copyright reasons. a) Draw an arrow indicating the direction that the RNA polymerases are transcribing. Why did you choose this direction? The mRNA molecules near the right side are short whereas the mRNA molecules towards the left are longer. The longer mRNA molecules will be towards the end of the gene. b) Below is a partial sequence of the above gene. Its orientation is the same as pictured above. Which strand is the template strand, the top or the bottom strand? Explain your choice. 5’ACTCGATGCTAG3’ 3’TGAGCTACGATC5’ mRNA is only made 5’  3’, so the top strand will be the template strand in the direction. c) What would be the mRNA sequence transcribed from the above sequence? Be sure to label the 5’ and 3’ ends. 5’ CUAGCAUCGAGU 3’ 7.012 Fall 2003 1