NEET BIOLOGY

CELL STRUCTURES AND FUNCTION

CELL CYCLE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What occurs during G1?
A
Checkpoint after S phase
B
Chromosomes line up at the equator.
C
The cell grows and develops.
D
Spindle fibers separate chromosomes to opposite poles of the cell.
Explanation: 

Detailed explanation-1: -In G1, cells accomplish most of their growth; they get bigger in size and make proteins and organelles needed for normal functions of DNA synthesis. Here, proteins and RNAs are synthesized, and, more especially the centromere and the other components of the centrosomes are made.

Detailed explanation-2: -Initially in G1 phase, the cell grows physically and increases the volume of both protein and organelles. In S phase, the cell copies its DNA to produce two sister chromatids and replicates its nucleosomes. Finally, G2 phase involves further cell growth and organisation of cellular contents.

Detailed explanation-3: -The stages of interphase are: G1 (Gap 1), in which the cell grows and functions normally. During this time, a high amount of protein synthesis occurs and the cell grows (to about double its original size) – more organelles are produced and the volume of the cytoplasm increases.

Detailed explanation-4: -Interphase is composed of G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth). At the end of interphase comes the mitotic phase, which is made up of mitosis and cytokinesis and leads to the formation of two daughter cells.

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