The CRISPR system is said to protect or preserve genome integrity in prokaryotic cells by acting as a type of "immune system." Explain how the CRISPR system works and its limitations
What will be an ideal response?
Answer: The CRISPR (clustered regularly interspaced short palindromic repeats) system is based on a region of the genome that contains DNA sequences from previously encountered foreign DNA separated by short palindromic repeats. The CRISPR region is translated into a long RNA molecule and then cleaved at each palindromic repeat to create short RNA molecules (crRNAs) that are complementary to foreign nucleic acids. If the crRNA binds to a piece of nucleic acid, associated proteins called Cas proteins will destroy the foreign nucleic acid and prevent it from recombining with the genome or replicating. The CRISPR system only works if the foreign DNA has homology with the DNA sequences in the CRISPR region of the genome. This means that novel phages or other DNA sequences would not be recognized or destroyed. Another limitation is that the CRISPR system might destroy DNA that contains useful genes or sequences if it were allowed to recombine with the genome. This could slow down evolution and adaptation.
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Water potential (?) can be thought of as the tendency for water to move from one place to another. In plants, it is made up mainly of solute potential and pressure potential
Hypothetical plant cells A and B are adjacent to each other. The solute potential (?S) of cell A is -0.35 MPa, and its pressure potential (?P) is +0.15 MPa. The solute potential (?S) of cell B is -0.30 MPa, and its pressure potential (?P) is +0.05 MPa. In which direction will net water movement occur? A) Neither; cells A and B are in equilibrium with each other. B) from cell A to cell B C) from cell B to cell A
Working in an experimental fertility clinic, a researcher removes one cell from an 8-cell stage chimpanzee embryo. What is the likely result?
A. Both the cell and the blastula will die. B. All the cells are already committed and therefore are not viable. C. The embryo from which the cell was removed still remains viable and can form a normal chimp. Clarify Question What is the key concept addressed by the question? What type of thinking is required? Gather Content What do you already know about early development? What other information is related to the question? Choose Answer Given what you now know, what information is most likely to produce the correct answer? Reflect on Process Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
The most amount of energy is available to
a. A. b. B. c. C. d. D. e. E.
Which of the following is not likely to be found in large quantities in an energy drink?
A. niacin B. fats C. folic acid D. caffeine E. amino acids