A protein contains an N-terminal ER signal sequence followed by several negatively charged amino acids, an internal ER stop-transfer sequence, and an internal ER start-transfer sequence (in order from N-terminal to C-terminal). The signal sequence is cleaved by signal peptidase upon lateral release from sec61. How will the protein orient in the ER membrane?

A. Lumenal N-terminal, cytosolic C-terminal
B. Lumenal N-terminal, cytosolic protein loop, lumenal C-terminal
C. Cytosolic N-terminal, lumenal protein loop, cytosolic C-terminal
D. Membrane-bound N-terminal, lumenal protein loop, cytosolic protein loop, lumenal C-terminal
E. The protein will be soluble and released into the ER lumen

You will create a molecular clock model for an arthropod gene. follow these guidelines to make your model: . your timeline will span from 90 million years ago to the present. the common ancestor in your model is an arthropod that lived 90 million years ago. the gene that you'll track codes for a protein in the species venom . the dna sequence youll track contains 10 nitrogen bases. you can choose the order of the bases and where the mutations occur. this gene mutates at a rate of approximately 0.76 base pairs every 17.1 million years. to build your model,/ calculate the estimated time period it takes for 1 base pair to mutate. the first time period will only show the common ancestor. at the beginning of the second time period, three lineages will diverge from the common ancestor, each with a different mutation in their gene sequences. the first and third descendant species will survive for the rest of the timeline. the second descendant species was extinct 50 million years ago. calculate how long it will take for one full base pair mutation to occur. explain your reasoning by constructing a mathematical equation