Question

During the ${ G }_{ 1 }$ phase of cell division following events occurs
(a) RNA and proteins are synthesized
(b) DNA and proteins are synthesized
(c) Cell prepares for M-phase
(d) Cell undergoes duplication

Answer 1

In ${ G }_{ 1 }$ phase metabolic changes prepare the cell for division. where the cell grows in preparation for DNA replication, and certain intracellular components, such as the centrosomes undergo replication. At a restriction point, the cell is committed to division and moves into the S phase.

Complete answer:
The process by which a parent cell divides into two or more daughter cells is called cell division which usually occurs as part of a larger cell cycle. The ordered sequence of events in a cell i. e cell cycle helps them in preparation for cell division through a four-stage process in which the cell increases in size (${ G }_{ 1 }$ stage), copies its DNA ( stage), prepares to divide (${ G }_{ 2 }$ stage), and divides (mitosis, or M, stage).
An intermediate phase occupying the time between the end of cell division in mitosis and the beginning of DNA replication during the S phase is called ${ G }_{ 1 }$. The cellular monitoring is. e it reviews the cellular environment and the cell size to ensure that the conditions are appropriate to support DNA replication during ${ G }_{ 1 }$. During ${ G }_{ 1 }$ phase The cell grows in size and synthesizes mRNA and proteins (known as histones) that are required for DNA synthesis. Cells can pause during ${ G }_{ 1 }$ if all are not ready to undergo DNA replication and enter a phase called ${ G }_{ 0 }$. ${ G }_{ 0 }$ can last days, weeks, or even years depending on a cell's preparedness to continue in the cell cycle. The cell will exit either ${ G }_{ 1 }$ when the cell has reached an appropriate size and is in a supportive environment for DNA replication or ${ G }_{ 0 }$.
So, the correct answer is, ‘RNA and proteins are synthesized’.

Additional information:

1. The process of cell division under a microscope was first discovered in 1835 by German botanist Hugo von Mohl as he worked over the green alga Cladophora glomerata.
2. The process of cell division was filmed for the first time in 1943 by Kurt Michel using a phase-contrast microscope.
3. Some proteins play a role in stimulating cell division. These proteins can be classified into four groups—growth factors, growth factor receptors, signal transducers, and nuclear regulatory proteins.
4. Some important checkpoints are present at the end of ${ G }_{ 1 }$ and the beginning of${ G }_{ 2 }$ are designed to assess DNA for damage before and after the S phase. A checkpoint during mitosis ensures that the cell’s spindle fibers are properly aligned in metaphase before the chromosomes are separated in anaphase. If they detected any DNA damage or abnormalities in spindle formation, the cell is forced to undergo programmed cell death or apoptosis.

Note: For the cell, the ${ G }_{ 1 }$ and${ G }_{ 2 }$ phases serve as checkpoints to make sure that it is ready to proceed in the cell cycle. If the cell isn’t ready now it will use the time to make proper adjustments that can include cell growth, correction or completion of DNA synthesis, and duplication of intracellular components. The next phase i.e. S phase involves the replication of chromosomes. All of them involve continued cell growth and an increase in the concentration of proteins found in the cell.