Consider statements about cell division: 1. Crossing over occurs in prophase I of meiosis. 2. Anaphase I involves the separation of homologous chromosomes. 3. Telophase II results in four diploid cells. Which are correct? MCQ with Answer and Explanation
Consider statements about cell division: 1. Crossing over occurs in prophase I of meiosis. 2. Anaphase I involves the separation of homologous chromosomes. 3. Telophase II results in four diploid cells. Which are correct?
A. 1, 2 and 3
B. 2 and 3 only
C. 1 and 3 only
D. 1 and 2 only
Answer: Option D
Solution (By JKExamLibrary)
During prophase I of meiosis, homologous chromosomes pair up and crossing over (exchange of genetic material) occurs at the pachytene stage. In anaphase I, the homologous chromosomes separate and move to opposite poles, while sister chromatids remain attached. Telophase II is the final stage of meiosis II, resulting in four genetically distinct haploid cells, not diploid cells. Thus, statements 1 and 2 are correct.
Explanation:
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Explanation:
Transformation is the uptake of free DNA from the surroundings and its incorporation into the bacterial genome. Conjugation requires cell-to-cell contact via pilus, transduction involves bacteriophage, translation is protein synthesis.
Explanation:
Blood group O lacks A and B antigens on red cells but contains both anti-A and anti-B antibodies in plasma. This makes it the universal donor for packed red cells but dangerous plasma donor. Group AB has no antibodies. So, the presence of both antibodies is correct.
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