You are studying swimming motility in a pathogenic bacillus. You create mutations in random genes and then test which mutations effect swimming motility by looking at the mutant cells under the microscope
One of the mutant bacteria can not swim anymore, but still rotates around in a one spot when you watch them. Using electron microscopy you discover that some parts of the flagella are still present in the cell wall, but no long flagella are visible. Which gene do you think is mutated (i.e., missing) and which motility-related parts are still present in this mutant?
What will be an ideal response?
Answer: The flagellar apparatus is put together in a particular order first the MS ring, anchoring proteins, and the hook extend off of the cytoplasmic membrane. Flagellin proteins then pass through the narrow filament channel and cap proteins finally are put onto the end when roughly 20,000 flagellin have been assembled. Flagellar growth thus occurs after the assembly of the basal body, rings, and hook. The basal body provides the rotation and uses the proton motive force to rotate the basal body. From the information given above, one can infer that the basal body and hook can still rotate, but the flagellin proteins are missing or defective so that no long flagella can form. This would explain why the cells might still rotate in place, but not be able to move forward rapidly.
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The process of cell division in a prokaryotic cell is called:
A. binary fusion. B. mitosis. C. binary fission. D. cytokinesis.
What would happen if your SA node and AV node fired at same time?
A. The QRS wave on an ECG would disappear, as it would be masked by the P wave. B. Your blood pressure would increase. C. The production of nitric oxide by your endothelial cells would increase. D. Blood would be forced back into the atria from the ventricles. E. Your stroke volume would decrease. 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 the SA and AV nodes? 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 3-nucleotide sequences in DNA that is transcribed into mRNA codons are the same 3 nucleotides
as the anticodons that bind to those codons. Indicate whether the statement is true or false.
The failure of chromosomes to separate during meiosis is called
A) crossing over B) genetic displacement C) non-disjunction D) disjunction