Author: Anonymous

Which of the following claims best explains why keratinocytes do not produce melanin?

According to the figure above, if you are a DNA analyst, you should conclude that …

Based on the DNA fingerprint below, which of these men is the father of this child?

Eukaryotes transcribe RNA from DNA that contains introns and exons. Alternative splicing is one posttranscriptional modification that can create distinct mature mRNA molecules that lead to the production of different proteins from the same gene. Figure 1 shows a gene and the RNA produced after transcription and after alternative splicing. A cell needs to metabolize the substrate illustrated in Figure 1 for a vital cellular function. Which of the following best explains the long-term effect on the cell of splicing that yields only enzyme C mRNA?  

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

Archaeologists unearthed a human skull with a small dried fragment of the scalp still attached.  They extracted a tiny amount of DNA from the scalp tissue. How could they obtain sufficient DNA for an analysis of the ancient’ man’s genes?

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?

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

What alarm is going off on the pump and what does it mean?