The S phase of a cell cycle occurs during interphase, before mitosis or meiosis, and is responsible for the synthesis or replication of DNA. In this way, the genetic material of a cell is doubled before it enters mitosis or meiosis, allowing there to be enough DNA to be split into daughter cells.
What happens to the DNA before a cell undergoes meiosis?
During meiosis, the cells needed for sexual reproduction divide to produce new cells called gametes. Gametes contain half as many chromosomes as the other cells in the organism, and each gamete is genetically unique because the DNA of the parent cell is shuffled before the cell divides.
What happens to the DNA before mitosis begins?
Before mitosis starts, all the chromosomes in the nucleus replicate their DNA to make identical copies. The nucleus now contains two sets of replicated chromosomes, twice as many as a normal body cell. … The replicated chromosomes are not visible as individual units – their DNA is loosely coiled.
What happens to DNA in each stage of mitosis?
This process involves replication of the cell’s chromosomes, segregation of the copied DNA, and splitting of the parent cell’s cytoplasm. … The outcome of binary fission is two new cells that are identical to the original cell.
Which of the following is a stage of mitosis?
Today, mitosis is understood to involve five phases, based on the physical state of the chromosomes and spindle. These phases are prophase, prometaphase, metaphase, anaphase, and telophase.
How much DNA is present in each phase of mitosis?
Recall that DNA is replicated during the S phase of the cell cycle. Thus during metaphase of mitosis, each chromosome (i.e., each chromatid pair) will contain two molecules of double stranded DNA (one molecule per sister chromatid).