Which statement is TRUE about the fluid from the hydrothermal vents?
A) The fluid contains large amounts of oxidized inorganic materials.
B) The fluid contains large amounts of reduced inorganic materials.
C) The fluid contains large amounts of organic material.
D) The fluid usually contains about equal amounts of organic and inorganic material.
Answer: B
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Read the following passage. Notice that there are numbers at the end of some of the sentences
Refer to these numbers when answering the question(s) below. Melanoma cells metastasize by leaving the primary tumor and entering the bloodstream, which carries them to distant parts of the body. The cancer cells leave the bloodstream by crossing the capillary basal lamina to enter another tissue (1). As a cancer researcher you think that somehow preventing the cancer cells from crossing the basal lamina of the blood vessels will inhibit metastasis (2). You believe that if you block the integrin receptors on the melanoma cells from binding to the extracellular matrix proteins of the basal lamina, then the cells will not be able to adhere to the basal lamina and therefore will not be able to migrate across it (3). You and your colleagues set about to make antibodies that will bind specifically to the integrins on the surface of the melanoma cells, preventing them from adhering to the proteins in the basal lamina. Once you have these integrin-specific antibodies, you test them on cancer cells in culture to see if they prevent the cells from crossing an artificial basal lamina. To do this, you and you colleagues set up nine cultures of cancer cells. You treat three cultures with the integrin-specific antibody. You treat three more cultures with a non-specific antibody that does not bind to integrins. Three cultures of cells are not treated with antibodies. (4). In the passage above, sentence number 2 is: A. support for their idea that blocking integrin function inhibits some tumor cells from binding the basal lamina. B. proof that their idea about blocking integrins will prevent metastasis. C. an observation. D. a prediction. E. a hypothesis.
A respiratory surface is indicated by
a. A. b. B. c. C. d. D. e. E.
Retroviruses are characterized by
a. an RNA core. b. integrating DNA into the host’s chromosome. c. the enzyme reverse transcriptase. d. having one strain that causes AIDS. e. all of these.
Which aspects of polymerase chain reaction (PCR) make it such an effective and critical laboratory tool?
PCR is able to produce large quantities of DNA in a very short period of time. PCR is inexpensive to perform and a relatively easy laboratory procedure to carry out. PCR is highly sensitive and can amplify even the smallest quantity of DNA into billions of copies. PCR is a vital tool in almost all genetic procedures performed in a laboratory today, and has a high rate of success. All of the above are reasons supporting the statement that PCR is an effective and critical laboratory tool.