You are working on a protein for a research project. The protein does not express well in prokaryotic expression systems so you decide to try a eukaryotic system, baker’s yeast, instead. As part of the expression system, you add a signal peptide to the protein so that it will be exported through the endomembrane system to the outside of the yeast cell. This makes purifying the protein much simpler. During the purification, you notice that the protein is heavier than it should be during gel filtration chromatography. This is confirmed by SDS-PAGE. What could be the reason that the protein has gained mass when expressed in the eukaryotic system?

You plan to synthesize a peptide to be used as a vaccine to treat melanoma, a particularly aggressive form of skin cancer. Normally, gp100, a protein on the surface of melanocytes, activates cell growth when it is bound by its ligand. Activation of the growth pathway depends on the presence of threonine in the ligand. The effective peptide vaccine will mimic the natural ligand, but won’t cause cell growth and division. Below is the sequence of the natural ligand:   LDMKTAG   In order to ensure your newly designed peptide vaccine does not cause cell growth upon binding, you must substitute the Threonine residue at position 5. What amino acid would you replace it with, bearing in mind that the peptide should still be similar enough to bind to the gp100 protein in the surface of melanocytes. Explain your choice. Your vaccine will be administered as a topical cream, and you require your peptide to have an overall neutral charge in order to be functional. At what pH should you formulate…

You are studying the effect of various mutations in this gene. The AG sequence (3’splice site) that is within intron 2 [adjacent to Exon 3] has been changed to a CC.  What would the resulting mRNA transcript look like? Draw a similar diagram as above and indicate the nucleotide lengths on the mRNA transcript.

You are studying a eukaryotic protein PKK in the lab. You fuse the DNA encoding GFP (green fluorescent protein) to the C terminus of the PKK gene. You also create the following GFP-PKK variants -GFP Wild- type: N- Signal sequence Transmembrane domain Kinase domain Variant 1: N- GFP Transmembrane domain Kinase domain Variant 2: N- -GFP Signal sequence Transmembrane domain Variant 3: N- -GFP Signal sequence Kinase domain Variant 4: N- -GFP Kinase domain If you examine wild-type PKK trafficking in a eukaryotic cell, which of the following are true? Select all that apply This fusion protein will be trafficked to the nucleus This fusion protein is a cell membrane protein This fusion protein will be trafficked to the Endoplasmic Reticulum This fusion protein is a nuclear protein

Describe the initiation step of bacterial transcription (make sure to include important enzymes, parts, and sequences in your answer) up to the beginning of elongation. What are three ways that transcription differs between bacteria and eukaryotes? (I'm not looking for types of RNA modification, just in terms of transcription)

Based on the electron micrograph shown, which of the following statements is/are correct/true? Select all that apply. You may select mutiple options. DNA and mRNAs are marked by arrows. DNA mRNAs #3 Left Right 1 μm You cannot determine relative mRNA lengths from this image You cannot determine the direction of transcription from this image the longest mRNA is on the right side ✔Direction of transcription is left to right O Direction of transcription is right to left the 5' end of the mRNA marked #3 is at the bottom O the longest mRNA is on the left side the 5' end of the mRNA marked #3 is at the top You cannot determine the 5' or 3' mRNA ends from this image

Part A Shown above is a schematic diagram of the E. coli leader peptidase (Lep) which has several basic amino acids in a cytoplasmic loop. Propose a mutant of Lep that would be a test of the "inside positive" rule for the orientation of proteins in membranes. Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. terminal reversed same (+) (-) center 1. Make mutant Lep that substitutes noncharged residues for the chains in the loop, and put charged side chains in 2. If the inside-positive rule applies, the mutant ought to have the membrane. Reset Help charged side positions. orientation in the

Shown below is a cartoon of a genetic oscillator. a) Convert into a Forrester diagram, state variables are D, m, E, S and P. As a reminder, dashed lines serve control/regulation. b) In a sentence, what causes the cyclic behavior in the formation of the product? DNA D mRNA Enzyme Substrate Product I 3