Two identical twins showed very similar methylation patterns when they were 4 years old, but these patterns diverged considerably by the time they were 40 years old. What is the most likely explanation for this?

Gitelman syndrome (GS) is a heritable disorder caused by a mutation in the SLC  gene that encodes a  Na+/Cl- cotransporter protein (A in Figure 1) that is expressed in kidney cells. When molecules or ions are moved by cotransporters, the molecules or ions must move across a membrane together, either in the same direction or in opposite directions. The Na+/Cl- cotransporter simultaneously transports Na+ and  Cl- from one region of the kidney (Region I) into the cell. Other transporters in kidney cell membranes include the  Na+/K+ ATPase (B in Figure 1) and a Na+/Ca2+ cotransporter D in Figure 1) that allow ions to move across the membrane between the kidney cell and a second region of the kidney (Region II ). Kidney cells also have channel proteins like the Ca2+ channel (C in Figure 1) that transports Ca2+ from Region I  into the kidney cell. A model representing the exchange of various ions between the kidney cell and the two extracellular regions is shown in Figure 1. The size of an ion’s symbol indicates the relative concentration of that ion in a given area. The larger symbol indicates the area of higher concentration, and the smaller symbol indicates the area of lower concentration.     Figure 1. Model representing the exchange of ions between a kidney cell and two isolated extracellular regions. The larger symbols indicate the areas of higher ion concentration, and the smaller symbols indicate the areas of lower ion concentration. Researchers have determined that there are a number of mutations to the SLC wild-type allele (SLC) that result in GS. One mutant allele, SLC-gs1, results from a single nucleotide deletion that creates a stop codon midway through the coding region of the gene. A second mutant allele, SLC-gs2, results from a mutation that disrupts the sequence of a splicing site between an intron and an exon, preventing the removal of an intron. To better understand how GS is inherited, researchers studied a number of families with a history of GS . The pedigree of one of these families is shown in Figure 2.   Figure 2. Pedigree of a family with a history of GS caused by two different mutant alleles

Which of the following statements best explains why there are fewer colonies on plate IV than on plate III?

The Trp operon is a coordinately regulated group of genes (trpA–trpE) that are required for tryptophan biosynthesis in E. coli. Based on the figure above, which of the following correctly describes the regulation of the Trp operon?

Imagine that you’ve isolated a yeast mutant that contains histones resistant to acetylation. What do you predict for this mutant?

Bacterial cells that contain green fluorescent protein (GFP) will fluoresce under ultraviolet light. Which of the following is the most likely outcome of replacing the lacZ gene in the E. coli lac operon with the gene encoding GFP?

Write one body paragraph that employs the following structure. Keep the lead language and labels in place. Just fill in the variables and write your sentences. Employ the skills outlined in the lectures and materials for this week. DO NOT REMOVE THE LABELS SUCH AS POINT, ILLUSTRATION, AND EXPLANATION. KEEP THEM IN YOUR SUBMISSION. YOU WILL GET ZERO POINTS IF YOU TURN IN WORK WITHOUT LABELS. KEEP THE LEAD LANGUAGE EXACTLY AS YOU SEE IT. JUST FILL IN THE VARIABLES. IF YOU DON’T USE THE LEAD LANGUAGE, YOU WILL GET ZERO POINTS.   Point (just fill in the variables): The reasons given to warrant the main points in the reading are O and L.  Illustration (TWO direct quotations with integration AND with MLA in-text citations):  Explanation (FIVE sentences):   Works Cited Entry: 

Using the Davis drug guide, match the following IV push medications with the correct IV push time  

Were the nurses’ actions correct while flushing, connecting the tubing, and setting the pump? If no, provide rationale explaining why.

PCl3(g) + Cl2(g) PCl5(g)        The system at equilibrium is represented by the box on the left. Then the volume of the vessel is decreased. The box in the middle represents the system before equilibrium is re-established. Please discuss the number of each type of molecule to represent the possible new equilibrium (more than one possible answer).