Cell Cycle and Cell Division
Cell Cycle and Cell Division: Cell cycle is a process of producing son cells. Cell
division is a part of the cell cycle. The cell cycle comprises a series of
growth stages that take place in a coordinated way for the correct cell
division.
Phases of a Cell Cycle
A complete cell
cycle requires a cell to grow, duplicate its content and split into two son
cells. In eukaryotic cells, this happens in two phases, i.e. Interphase and
Mitosis. These two phases are developed in detail in the chapter on cell cycle
and cell division in class 11. Interphase is divided into three stages – Gap 1
(G1), Conflation (S), and Gap 2 (G2); mitosis is further divided into four
stages – prophase, metaphase, anaphase, and telophase. Mitosis is also
appertained to as the M phase.
Cell Cycle and Cell Division
• Interphase is the phase between the two consecutive M
phases; the factual cell division occurs in the M phase.
• Also known as the
introductory phase. In the first gap (G1) of the interphase, the cell grows and
accumulates the energy needed for replication.
• After G1, comes the
S phase or the conflation phase of the interphase. Then the identical dyads of
DNA motes are formed through the process of DNA replication. These identical
motes are appertained to as family-chromatids. The protein is also synthesised
then for mitosis.
• The
family-chromatids are now two independent cells and start accumulating the
energy to enter the introductory phase.
• Still, some cells don't enter the introductory phase
again as they don't need farther division or some need occasional division. In
this case, these cells enter the inactive stage called G0 or the inert stage.
The M Phase or Stages in Mitosis
Cell Cycle and Cell Division: As mentioned before, this phase is central to the process of the factual cell division. It's also appertained to as the equational division.
The M phase is also divided into four stages explained as
follows
• Prophase – It's
the first stage of the M phase and comprises S and G2 phases of the interphase.
In this stage, the chromosomes condense and the nuclear envelope breaks down.
The spindle fibres crop from the centrosomes and the nucleolus disappears.
• Metaphase – Each
family chromatid is attached to the spindle fibre that began from the contrary
pole.
• Anaphase – After
attaching to the spindle fibre from the contrary pole in metaphase, the
cohesion protein of family chromatids breaks down. Due to this, the family
chromatids are pulled towards the contrary poles.
• Telophase – In this stage, the chromosomes arrive at the
contrary poles and begin to decondense. The nuclear envelope surrounds each set
of chromosomes and the mitotic spindle breaks down.
Cytokinesis
Cytokinesis comes
after mitosis and is the division of cytoplasm. The chapter on Cell Cycle and
Cell Division in Class 11 also studies Cytonkinesis which occurs else in beast
and factory cells. In beast cells, a fractionalization crinkle separates the
son cells. In- factory cells, a new cell wall called the cell plate separates
the two son cells.
Mitosis and Meiosis
As explained in the chapter on cell cycle and cell division
of class 11, mitosis and meiosis are two types of cell division. In mitosis,
the cell undergoes the duplication process where it duplicates its chromosomes
and also splits into two identical son cells. Still, in meiosis, the cell
reduces the number of chromosomes during the division process in the son cells.
Go through the ensuing sections to understand the difference between these two
cell divisions.
Cell Cycle and Cell Division
What's Mitosis?
Confined to just
diploid cells, Mitosis happens when a parent cell splits to produce two
identical son cells. Studying Cell Cycle and Cell Division in Class 11, you'll
also get to learn about its significance in terms of cell division during the
life of an organism. The main end of mitosis is to grease growth and replace
those cells which are worn out and not essential for the life of an organism.
Cell Cycle and Cell Division
Significance of Mitosis
After explaining the conception of mitosis, mentions the main features of its
significance
. • Mitosis produces son cells with identical genetics.
This helps in the growth and development of both the cells and the organism.
• The nonstop
division of cells to maintain the nucleo-cytoplasmic rate plays an essential
part in cell form.
• The nonstop growth
of the shops is the result of mitotic division.
• Since meiosis doesn't beget any inheritable variation, it
maintains the originality of the organism type from generation to generation.
Meiosis
The chapter on Cell
Cycle and Cell Division describes the process of meiosis as a
technical kind of cell division through which the number of chromosomes is
reduced to half, performing in the product of 4 haploid cells.
The process involves two successional cycles of nuclear and cell division videlicet
.Meiosis II – This meiotic division is subdivided into
prophase II, metaphase II, anaphase II and telophase II
Cell Cycle and Cell Division
. Significance
of Meiosis
Moving to the coming section of Cell Cycle and Cell Division in Class 11, you'll get to learn about the significance of Meiosis which is as follows
. • The chromosome number is maintained among sexually
reproducing organisms.
• The crossing-over produces a new combination of
chromosomes, adding the inheritable variability in every generation.
• It also allows
inheritable mutation and the salutary mutations are carried out by the process
of natural selection.
• The motherly and
paternal processes are independent of each other. Thus, the traits that are
controlled by chromosomes are rearranged after every reproduction.