CELL STRUCTURES AND FUNCTION
CELL CYCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Crossing-over occurs prior to cell division.
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Mutations are corrected before the cell divides.
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Genetic variation is created in daughter cells.
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Each daughter cell gets an exact copy of the cell’s DNA.
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Detailed explanation-1: -Cells must replicate their DNA before they can divide. This ensures that each daughter cell gets a copy of the genome, and therefore, successful inheritance of genetic traits. DNA replication is an essential process and the basic mechanism is conserved in all organisms.
Detailed explanation-2: -The chromosomes now consist of two sister chromatids. Mitosis separates these chromatids, so that each new cell has a copy of every chromosome. The copied chromosomes consist of two chromatids joined at the centromere. The process of mitosis involves a number of different stages.
Detailed explanation-3: -Note:Replication of DNA molecule (duplication of DNA) occurs during S phase of Interphase. In this way, the genetic material of a cell is doubled before it enters the division phase, where division of genetic material takes place.
Detailed explanation-4: -The cell cycle has two major phases: interphase and the mitotic phase (Figure 6.3). During interphase, the cell grows and DNA is replicated.
Detailed explanation-5: -The cell has multiple mechanisms to ensure the accuracy of DNA replication. The first mechanism is the use of a faithful polymerase enzyme that can accurately copy long stretches of DNA. The second mechanism would be for the polymerase to catch its own mistakes and correct them.