ATI RN
Immune System Disorders Quizlet Questions
Question 1 of 5
The bacterial cytoplasmic membrane contains:
Correct Answer: A
Rationale: The correct answer is A because bacterial cytoplasmic membranes typically contain ester-linked phospholipids but no sterols. Ester-linked phospholipids are the main component of bacterial cell membranes, providing structure and function. Sterols, like cholesterol, are not commonly found in bacterial membranes. Choice B is incorrect because sterols are not present in bacterial membranes. Choice C is incorrect because ether-linked phospholipids are more commonly found in archaea, not bacteria. Choice D is incorrect because sulfolipids and glycolipids are not primary components of bacterial cytoplasmic membranes.
Question 2 of 5
NAD and FAD are hydrogen carriers, but cytochromes are electron carriers in bacteria. What happens to the protons (Hâº) in electron transport chains?
Correct Answer: D
Rationale: The correct answer is D because in the electron transport chain, protons (H⁺) are pumped across the membrane to create a proton gradient. This gradient is utilized by ATP synthase to produce ATP. Therefore, protons go into solution outside the cytoplasmic membrane. Choices A and B are incorrect because protons do not simply stay in the cytoplasm or get taken back by NAD and FAD. Choice C is incorrect as protons do not directly form water when carried by cytochromes.
Question 3 of 5
Choose the correct sequence in an allergic reaction.
Correct Answer: C
Rationale: Rationale for Answer C: 1. Allergen exposure triggers B cells to produce IgE antibodies specific to the allergen. 2. IgE antibodies bind to mast cells sensitizing them. 3. Upon re-exposure to allergen, allergen binds to IgE on mast cells. 4. This triggers release of histamine and other chemicals causing allergic symptoms. Summary: - Choice A: Incorrect because B cells do not produce IgE antibodies before allergen exposure. - Choice B: Incorrect because IgE antibodies are produced by B cells, not the other way around. - Choice D: Incorrect because histamine is released after allergen binds to IgE on sensitized mast cells.
Question 4 of 5
If you were to observe the activity of methylated DNA, you would expect it to
Correct Answer: C
Rationale: The correct answer is C because methylation of DNA typically results in the inhibition or slowing down of transcription. Methylated DNA attracts proteins that bind to it, preventing transcription factors from accessing the DNA and initiating transcription. This interference with the transcription process leads to gene silencing or reduced gene expression. A: DNA unwinding in preparation for protein synthesis is unrelated to DNA methylation. B: Continuous replication is not a typical consequence of DNA methylation. D: Methylation does not directly induce protein synthesis but rather affects transcription by influencing gene expression.
Question 5 of 5
The reason for using Taq polymerase for PCR is that
Correct Answer: D
Rationale: The correct answer is D because Taq polymerase is heat-stable, allowing it to withstand the high temperatures used in PCR cycles without denaturing. This heat stability is crucial for the repeated heating and cooling cycles in PCR. Choice A is incorrect because Taq polymerase does not need to be complementary to primers. Choice B is incorrect because the amount needed is not the main reason for using Taq polymerase. Choice C is incorrect because binding affinity to primers is not the primary reason for using Taq polymerase.