Cow's milk allergy (CMA) and lactose intolerance both result from dietary exposure to cow's milk and are often confused. CMA is caused by an abnormal inflammatory response to one or more proteins in cow's milk. Although more than one mechanism appears to be involved in generating this response, the antibody- mediated response is the best understood. Development of the antibody-mediated response occurs in two stages, the first being the generation of an abnormal immune response during initial exposure to milk proteins and the second being the generation of an inflammatory response upon subsequent exposure. Symptoms of antibody-mediated CMA may include hives and respiratory difficulty. Anaphylactic shock. rarely occurs but can be fatal if not treated immediately. Lactose intolerance, also known as lactase deficiency, is a condition that results from insufficient synthesis of the enzyme lactase, which converts lactose into glucose and galactose. Although all healthy newborns produce sufficient levels of lactase, two distinct phenotypes exist in adults: lactase persistence (LP) (includes heterozygotes) and lactase non-persistence (LNP). LP adults continue to produce lactase into adulthood, whereas LNP individuals do not. It has been suggested that the LP phenotype is the result of a mutation event that coincided with the domestication of dairy animals thousands of years ago in areas such as northwestern Europe and within some Afro-Arabian nomadic populations. In Northwestern Europeans, sets of alleles located closely together on the same chromosome (haplotypes) associated with the LP phenotype contain several single nucleotide polymorphisms (SNPs). However, only one appears to be directly responsible for this phenotype; the others are silent. By comparison, several different SNPs appear to be directly responsible for the LP phenotype in Afro-Arabian LP-associated haplotypes. A particular diploid organism is heterozygous in each of 3 unlinked genes. Considering only these 3 genes, how many different types of gametes can this organism produce? OA. 3 OB. 4 O C. 6 OD. 8 Consider an experiment that consists of two ionic solutions separated by a membrane that contains a ligand-gated potassium channel. The lack of current generation in response to addition of ligand is explained by: 1. lack of potassium in either solution. II. the presence of potassium in only one solution. III. equal concentrations of potassium in the two solutions. OA. I only OB. I and II only OC. I and III only OD. II and III only Based on the information in the passage, the mutation that causes the LP phenotype is most likely located in: O A. an intron within the lactase gene. O B. the coding sequence of the lactase gene. O C. an enhancer sequence of the lactase gene. O D. the stop codon at the end of the lactase gene.