Which of the following statements about the differential expression of human genes is correct? A. Differential expression does not occur during embryogenesis (development of the embryo). B. The unused genes in differentiated cells no longer retain the potential to be expressed. C. Gene expression patterns of all cells are identical. D. Every cell nucleus contains the complete genome established in the fertilized egg.

An example of inappropriate expression of a protein and what could be learned from this type of experiment include(s); a. All of these would help a scientist to learn the functions of a protein. b. Limiting the level of protein to identify the variety of functions of a protein. c. Producing too much of a protein to identify the functions of a protein d. Producing a protein too early in development to identify the function of that protein

3. Figure 2 illustrates how Pitx1 transcription is regulated in different tissues. The center image is that of a stickleback embryo. The drawings in the surrounding boxes show the Pitx1 gene region and activator proteins present in the jaw, pelvis, eye, or pituitary tissues. a. List all the tissues shown in Figure 2 that express the Pitx1 gene. b. If a fish does not produce activator 1 proteins because of a mutation in the gene that encodes those proteins, Pitx1 will be expressed in which of the following tissues? c. If a fish does not produce activator 3 proteins, Pitx1 will be expressed in which of the following tissues? d. A fish inherits a mutation in the Pitx1 coding region. This is a nonsense mutation that introduces a premature stop codon, resulting in a nonfunctional protein. Where would you expect Pitx1 to be expressed in this scenario?

Unusually high levels of Mdr1 provide stem cells with a. Nutrients needed b. Protection of their genomes from mutagenic agents c. Apoptotic factors d. Ability to differentiate