LABORATORY REVIEW
MITOSIS AND MEIOSIS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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G1phase
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S phase
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G2 phase
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M phase
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Detailed explanation-1: -Cytarabine is converted to the triphosphate form within the cell and then competes with cytidine for incorporation into DNA. Because the arabinose sugar sterically hinders the rotation of the molecule within DNA, DNA replication ceases, specifically during the S phase of the cell cycle.
Detailed explanation-2: -Errors may occur during the DNA replication resulting in mutations and possibly the development of cancer. Cells have mechanisms to correct errors due to faulty DNA replication. Many chemotherapy agents target the S phase of the cell cycle.
Detailed explanation-3: -Translocations involve chromosome breakage and exchange of chromosome fragments. One such translocation, found in over 95% of chronic myeloid leukemias (CML) as well as some acute lymphoblastic leukemias (ALL), occurs between chromosomes 9 and 22.
Detailed explanation-4: -S phase. In S phase, the cell synthesizes a complete copy of the DNA in its nucleus. It also duplicates a microtubule-organizing structure called the centrosome. The centrosomes help separate DNA during M phase.