The life cycle of eukaryotic cells can generally be divided into four stages and a typical cell cycle is shown in Figure \(\PageIndex{13}\). When a cell is produced through fertilization or cell division, there is usually a lag before it undergoes DNA synthesis (replication). This lag period is called Gap 1 (G1), and ends with the onset of the DNA synthesis (S) phase, during which each chromosome is replicated. Following replication, there may be another lag, called Gap 2 (G2), before mitosis (M). Cells undergoing meiosis do not usually have a G2 phase. Interphase is as term used to include those phases of the cell cycle excluding mitosis and meiosis. Many variants of this generalized cell cycle also exist. Some cells never leave G1 phase, and are said to enter a permanent, non-dividing stage called G0. On the other hand, some cells undergo many rounds of DNA synthesis (S) without any mitosis or cell division, leading to endoreduplication. Understanding the control of the cell cycle is an active area of research, particularly because of the relationship between cell division and cancer.
The amount of DNA within a cell changes following each of the following events: fertilization, DNA synthesis, mitosis, and meiosis (Fig 2.14). We use “c” to represent the DNA content in a cell, and “n” to represent the number of complete sets of chromosomes. In a gamete (i.e. sperm or egg), the amount of DNA is 1c, and the number of chromosomes is 1n. Upon fertilization, both the DNA content and the number of chromosomes doubles to 2c and 2n, respectively. Following DNA replication, the DNA content doubles again to 4c, but each pair of sister chromatids is still counted as a single chromosome (a replicated chromosome), so the number of chromosomes remains unchanged at 2n. If the cell undergoes mitosis, each daughter cell will return to 2c and 2n, because it will receive half of the DNA, and one of each pair of sister chromatids. In contrast, the 4 cells that come from meiosis of a 2n, 4c cell are each 1c and 1n, since each pair of sister chromatids, and each pair of homologous chromosomes, divides during meiosis. 
The life cycle of eukaryotic cells can generally be divided into four stages and a typical cell cycle is shown in Figure \(\PageIndex{13}\). When a cell is produced through fertilization or cell division, there is usually a lag before it undergoes DNA synthesis (replication). This lag period is called Gap 1 (G1), and ends with the onset of the DNA synthesis (S) phase, during which each chromosome is replicated. Following replication, there may be another lag, called Gap 2 (G2), before mitosis (M). Cells undergoing meiosis do not usually have a G2 phase. Interphase is as term used to include those phases of the cell cycle excluding mitosis and meiosis. Many variants of this generalized cell cycle also exist. Some cells never leave G1 phase, and are said to enter a permanent, non-dividing stage called G0. On the other hand, some cells undergo many rounds of DNA synthesis (S) without any mitosis or cell division, leading to endoreduplication. Understanding the control of the cell cycle is an active area of research, particularly because of the relationship between cell division and cancer. Figure \(\PageIndex{13}\): A typical eukaryotic cell cycle.(Original-Deyholos-CC:AN)The amount of DNA within a cell changes following each of the following events: fertilization, DNA synthesis, mitosis, and meiosis (Fig 2.14). We use “c” to represent the DNA content in a cell, and “n” to represent the number of complete sets of chromosomes. In a gamete (i.e. sperm or egg), the amount of DNA is 1c, and the number of chromosomes is 1n. Upon fertilization, both the DNA content and the number of chromosomes doubles to 2c and 2n, respectively. Following DNA replication, the DNA content doubles again to 4c, but each pair of sister chromatids is still counted as a single chromosome (a replicated chromosome), so the number of chromosomes remains unchanged at 2n. If the cell undergoes mitosis, each daughter cell will return to 2c and 2n, because it will receive half of the DNA, and one of each pair of sister chromatids. In contrast, the 4 cells that come from meiosis of a 2n, 4c cell are each 1c and 1n, since each pair of sister chromatids, and each pair of homologous chromosomes, divides during meiosis. Figure \(\PageIndex{14}\): Changes in DNA and chromosome content during the cell cycle. For simplicity, nuclear membranes are not shown, and all chromosomes are represented in a similar stage of condensation.(Original-Deyholos-CC:AN)If you're seeing this message, it means we're having trouble loading external resources on our website. If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked. If you're seeing this message, it means we're having trouble loading external resources on our website. If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked. Which of the following best describes how the amount of DNA in the cell changes during M phase? The amount of DNA is halved as the cell divides into two daughter cells.... read more › How does the amount of DNA in a cell change during the cell cycle?So during a mitotic cell cycle, the DNA content per chromosome doubles during S phase (each chromosome starts as one chromatid, then becomes a pair of identical sister chromatids during S phase), but the chromosome number stays the same.... view details › What happens during the cell cycle that changes DNA?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.... read more › What happens during the M phase?Cell division occurs during M phase, which consists of nuclear division (mitosis) followed by cytoplasmic division (cytokinesis). The DNA is replicated in the preceding S phase; the two copies of each replicated chromosome (called sister chromatids) remain glued together by cohesins.... read more › What happens to the amount of DNA in the cell during interphase?Because DNA is duplicated during interphase before the cell undergoes mitosis, the amount of DNA in the original parent cell and the daughter cells are exactly the same. Both genetics, as well as external factors, can play a role in the development of cancer.... see more › Does the amount of DNA change during meiosis?During Meiosis, there is no change in no. of DNA molecule and chromosomes in prophase and metaphase.... see more › During which portion of the cell cycle does the amount of DNA in the cell decrease by half?If the cell undergoes mitosis, each daughter cell will return to 2c and 2n, because it will receive half of the DNA, and one of each pair of sister chromatids.... see details › What happens to a cell after M phase of cell cycle?During G2 phase, the cell is again stable. During M phase, nucleocytoplasmic index decreases. After M phase or mitosis when the cell divides, nucleoplasmic index returns to normal.... see more › What happens to the amount of DNA in the nucleus just before the beginning of mitosis?What happens to the amount of DNA in the nucleus just before the beginning of mitosis? The amount of DNA doubles. Why are chromosomes called "doubled chromosomes" just before mitosis begins? The amount of DNA in the chromosomes double.... see more › During which phase of the cell cycle does DNA replication occur?S phase is the period during which DNA replication occurs.... read more › What is the M phase?M phase. During the mitotic (M) phase, the cell divides its copied DNA and cytoplasm to make two new cells. M phase involves two distinct division-related processes: mitosis and cytokinesis.... see more › What does the M phase stand for?M stands for mitosis. This is where the cell actually partitions the two copies of the genetic material into the two daughter cells. After M phase completes, cell division occurs and two cells are left, and the cell cycle can begin again.... continue reading › What are the four steps that occur during the M phase?These basic events of mitosis include chromosome condensation, formation of the mitotic spindle, and attachment of chromosomes to the spindle microtubules. Sister chromatids then separate from each other and move to opposite poles of the spindle, followed by the formation of daughter nuclei.... continue reading › What happens to the amount of DNA when it replicates itself?The result of DNA replication is two DNA molecules consisting of one new and one old chain of nucleotides. This is why DNA replication is described as semi-conservative, half of the chain is part of the original DNA molecule, half is brand new.... see more › What happens during each phase of interphase?During interphase, the cell grows and the nuclear DNA is duplicated. Interphase is followed by the mitotic phase. During the mitotic phase, the duplicated chromosomes are segregated and distributed into daughter nuclei. The cytoplasm is usually divided as well, resulting in two daughter cells.... continue reading › What happens in the phases of interphase?Interphase is the phase of the cell cycle in which a typical cell spends most of its life. Interphase is the 'daily living' or metabolic phase of the cell, in which the cell obtains nutrients and metabolizes them, grows, replicates its DNA in preparation for mitosis, and conducts other "normal" cell functions.... see more › During which phase of the cell cycle does the amount of DNA in a cell remains at the 4n?Solution: In the G2 and M phase of the cell cycle, the amount of DNA in a cell remains at 4C level when the initial amount is denoted as 2C.... see details › Why does the amount of DNA change during the cell cycle and why is it important?During the G1 phase, each chromosome contains one molecule of DNA. But when the reproductive process begins, the cell will need two sets of DNA: one for itself and one for the offspring cell. During the S phase, the cell replicates its genetic material so that each chromosome will contain two molecules of DNA.... see details › During which stage of the cell cycle would a cell contain the least total amount of DNA?Only G1 phase precedes the S phase and has half the amount of DNA as the rest of the cell cycle; therefore, cells in the G1 phase have the least amount of DNA.... view details › During which phase of the cell cycle is cell growth most significant?Interphase is the longest phase of the cell cycle. Cell growth is central to the cell cycle, and this is the primary purpose for interphase. At the end of this phase, there is double the amount of DNA, centrioles have replicated, and the cell is big enough for cell division.... see details › During which stage of the cell cycle is cell growth and replication of organelles most significant?So the correct answer is the 'G1 phase'.... read more › What must happen to the DNA strands in the nucleus before the cell can divide Why?What must happen to the DNA strands in the nucleus before the cell can divide? Why? The DNA must copy itself. This is necessary so that each of the two cells produced will have the correct number of chromosomes.... see more › What refers to the amount of DNA present at a specific stage or time in the life of an organism?Life cycles refer to the amount of DNA present at a specific stage or time in the life of an organism.... view details › Which of the following describes the number of chromosomes and amount of DNA in a gamete?This is the 2n, or diploid, state. Human gametes have 23 chromosomes or one complete set of chromosomes. This is the n, or haploid, state.... view details › During which stage of the cell cycle does DNA replication occur quizlet?Interphase is the stage of the cell cycle when the DNA replication occurs.... see details › When in the cell cycle does DNA replication occur quizlet?During which phase of the cell cycle does DNA duplication, or replication, take place? DNA replicates during interphase. This process provides each new daughter cell with a full complement of genetic material. When a double helix of DNA is replicated, two complete helices are formed.... see more › During which stage of the cell cycle is DNA copied quizlet?During which stage of the cell cycle is the DNA copied? The DNA is copied during the synthesis phase.... continue reading › What two process make up the M stage?During the M phase or mitotic phase, a cell divides into two daughter cells. Nuclear division and cytoplasmic division takes place during the M phase, which is known as karyokinesis and cytokinesis, respectively. During karyokinesis, there is division of the nucleus.... read more › What happens at the M phase checkpoint?The M checkpoint is also known as the spindle checkpoint: here, the cell examines whether all the sister chromatids are correctly attached to the spindle microtubules.... continue reading › Why is the M phase the shortest?G1 phase, S phase, G2 phase and M phase. The total time duration of a cell cycle is for 24 hours. Among which, G1 phase is of about 11 hours, S phase is of about 7 hours, G2 phase is of about 4 hours and M phase is of 2 hours. Therefore, M phase is called the shortest phase of the cell cycle.... continue reading › How is the amount of DNA maintained in each generation?The amount of DNA is maintained in each generation by a specialized mode of cell division called meiosis which produces specialized male and female germ cells called gametes which are haploid. One male and female gamete fertilize to give rise to a diploid zygote which has the same chromosome number as the parent.... see details › What happens to the amount of DNA in the nucleus just before the beginning of mitosis?What happens to the amount of DNA in the nucleus just before the beginning of mitosis? The amount of DNA doubles. Why are chromosomes called "doubled chromosomes" just before mitosis begins? The amount of DNA in the chromosomes double.... continue reading › In which stage of cell amount of DNA gets doubled?In the 'S' phase of the cell cycle, the amount of DNA doubles in each cell. Mitosis is divided into two main phases – the Interphase and M phase. The M phase refers to the actual cell division.... view details › Which phase has the least amount of DNA?Only G1 phase precedes the S phase and has half the amount of DNA as the rest of the cell cycle; therefore, cells in the G1 phase have the least amount of DNA.... see details › |
Which of the following best describes how the amount of DNA in the cell changes during M phase?
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