PCR involves a heating step, followed by a cooling step, and then DNA synthesis. What is the primary reason for why this cooling step is necessary?  

  You are interested in examining the Psf gene. It is known that Psf is produced when cells are exposed to high levels of both calcium (Ca2+) and magnesium (Mg2+). MetA, MetB, and MetC are important for binding to the promoter of the Psf gene and are involved in regulating its transcription. MetA binds to the “A” site in the promoter region, MetB to the “B” site, and MetC to the “C” site. You create binding-site mutations in the A, B, and C sites and observe what happens to transcription of the Psf gene. Your results are summarized in Table 8-1.   Table 8-1   Which of the following proteins is/are likely to act as (a) gene activator(s)?  

  During gel electrophoresis, DNA fragments  

The strict procedural rules that govern courts

Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a colorblind son. What are the genotypes of the parents?   XN = dominant: normal color vision   Xn = recessive: colorblind  

Use the figure and the following description to answer the question below.   In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in the figure, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square.  Which of the boxes marked 1-4 correspond to plants with dark leaves?

As the telegraph became a new tool of communication,  which  company offered its service? A. American Telephone and Telegraph B. Western Telegrams Service C. National Union  D. All of these

Once the federal government decided to fund the expansion of the railroad, which companies were awarded contracts to accomplish the  task? A. Missouri Pacific B. Union Pacific C. Central Pacific D. Western Pacific

While people may clamor for their freedom,  few are able to distinguish the various interpretations of  it. Does the image below capture that debate?

Which of the following orbitals does not exist?