Question

describe the control of cycle in dividing cells

Answer 1

The cell cycle or cell-division cycle is the series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells. In bacteria, which lack a cell nucleus, the cell cycle is divided into the B, C, and D periods. The B period extends from the end of cell division to the beginning of DNA replication. DNA replication occurs during the C period. The D period refers to the stage between the end of DNA replication and the splitting of the bacterial cell into two daughter cells.[2] In cells with a nucleus, as in eukaryotes, the cell cycle is also divided into three periods: interphase, the mitotic (M) phase, and cytokinesis. During interphase, the cell grows, accumulating nutrients needed for mitosis, preparing it for cell division and duplicating its DNA. During the mitotic phase, the chromosomes separate. During the final stage, cytokinesis, the chromosomes and cytoplasm separate into two new daughter cells. To ensure the proper division of the cell, there are control mechanisms known as cell cycle checkpoints.

The cell-division cycle is a vital process by which a single-celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells, and some internal organs are renewed. After cell division, each of the daughter cells begin the interphase of a new cycle. Although the various stages of interphase are not usually morphologically distinguishable, each phase of the cell cycle has a distinct set of specialized biochemical processes that prepare the cell for initiation of cell divisions.

Answer 2

The cell cycle describes a cell's life from the time it is first formed to the time it splits into two new cells. The cell cycle is divided into two main stages, the mitotic stage and the interphase stage. But in typical science fashion, these two main stages are further broken down.

The mitotic stage describes when a cell is actively replicating. During mitosis, the nucleus, which holds the cell's genetic information, is divided. During cytokinesis, the rest of the cell is divided. The result is two newly formed, identical cells.

The main stage of the cell cycle is called interphase. Interphase takes up most of the cell cycle - on average, 90% of a cell's life is spent in interphase. During this time, the cell lives its life as normal, performing all of its usual functions. It also begins to prepare for cell division, doubling in size and replicating its DNA.

Interphase is broken down into three main stages: G1, S, and G2. During the S phase, the cell's DNA is copied so that each new cell has all the information it needs. G1 and G2 phases get their name from being 'gaps', or times when the cell takes a break from replicating. These two phases are important for the control of cell division. In order for a cell to continue through the cell cycle, it must pass certain criteria during the gap phases.