Name and explain the various stages of the cell cycle.
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The cell cycle is a series of events that take place in a cell leading to the duplication of its DNA and the subsequent division of the cell to produce two daughter cells.
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A cell cycle consists of two phases:
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A non-dividing phase called the interphase.
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A dividing phase called the M-phase or mitosis.
Interphase:
1.During interphase, the two small daughter cells produced from a mother cell prepare for the next cell division and attain the same size as the mother cell.
2.The interphase includes three phases. These are:
1.First growth phase (G1): RNA and proteins are synthesised and the volume of cytoplasm increases.
2.Synthesis phase (S): More DNA is synthesised and the chromosomes are duplicated.
3.Second growth phase (G2): This is a shorter growth phase, in which RNA and proteins necessary for cell division continue to be synthesised
Mitosis includes two steps viz. karyokinesis and cytokinesis.
1.Karyokinesis: It is the division of the nucleus during cell division. It occurs in four phases:
2.Prophase: Chromosomes become short and thick and are clearly visible inside the nucleus. They duplicate to form two chromatids.
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Metaphase: The duplicate chromosomes arrange on the equatorial plane. Each chromosome gets attached to a spindle by its centromere.
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Anaphase: The centromere attaching the two chromatids divides and the two sister chromatids of each chromosome separate and are drawn apart towards opposite poles.
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Telophase: The spindle apparatus disappears. Chromosome becomes thinner and turns into a network of chromatin threads.
Cytokinesis: It marks the splitting of the cell cytoplasm into the resulting daughter cells after telophase. A furrow appears in the middle of the cell membrane which deepens and finally splits the cytoplasm into two, thus producing two new cells.
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Mitosis is the cell division in which one parent cell divides into two diploid identical daughter cells.
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The cell cycle is a series of events that take place in a cell leading to the duplication of its DNA and the subsequent division of the cell to produce two daughter cells.
-
A cell cycle consists of two phases:
-
A non-dividing phase called the interphase.
-
A dividing phase called the M-phase or mitosis.
Interphase:
1.During interphase, the two small daughter cells produced from a mother cell prepare for the next cell division and attain the same size as the mother cell.
2.The interphase includes three phases. These are:
1.First growth phase (G1): RNA and proteins are synthesised and the volume of cytoplasm increases.
2.Synthesis phase (S): More DNA is synthesised and the chromosomes are duplicated.
3.Second growth phase (G2): This is a shorter growth phase, in which RNA and proteins necessary for cell division continue to be synthesised
Mitosis includes two steps viz. karyokinesis and cytokinesis.
1.Karyokinesis: It is the division of the nucleus during cell division. It occurs in four phases:
2.Prophase: Chromosomes become short and thick and are clearly visible inside the nucleus. They duplicate to form two chromatids. -
Metaphase: The duplicate chromosomes arrange on the equatorial plane. Each chromosome gets attached to a spindle by its centromere.
-
Anaphase: The centromere attaching the two chromatids divides and the two sister chromatids of each chromosome separate and are drawn apart towards opposite poles.
-
Telophase: The spindle apparatus disappears. Chromosome becomes thinner and turns into a network of chromatin threads.
Cytokinesis: It marks the splitting of the cell cytoplasm into the resulting daughter cells after telophase. A furrow appears in the middle of the cell membrane which deepens and finally splits the cytoplasm into two, thus producing two new cells. -
Mitosis is the cell division in which one parent cell divides into two diploid identical daughter cells.
