Question

cell in human body reproduces. what process does it use? describe the steps in the cell cycle, and celldivision of this cell. how is this process controlled in your cell? what types of genes are involved here? what happens if that control is lost? give an example of this potential loss of control

Answer 1

The reproduction of the cells can be done by the cell cycle.During the process of cell cycle there are two stages:

1. Interphase 2. Mitotic phase

1. Interphase during these phase the cells DNA replication takes place. They contains G1,S phase,G2 phase.

G1 phase: the protiens,organalles and enzymes are made for DNA replication.

S phase: in this phase the DNA synthesis takes place.

G2 phase: in this phase assembly and formation of microtubules and spindle fibres which is important in M phase.

In these phases they have check points which checks that every thing is normal if incase of damaged these checkpoint stop the process and sent the cell to G0 stage where they repair or undergoes apoptosis.

Mitotic phase: In this phase cells undergoes cell division by forming to daughter cell.The steps involved in mitosis are:

Prophase,metaphase,anaphase and telophase

Prophase: where chromosome will be in condensed form

Metaphase: the chromosome align in metaphase plate.

Anaphase: during these phase sister chromatids moves towards the opposite poles.

Telophase: where cell starts diving into two daughter cell.

these cell cycle stages are completed by passing each checkpoint.each step is activated when the cyclins are activated . Cyclins are activated by binding to the cyclin dependent kinases.cyclins are specific and different in each step.

M phase contains check point in between metaphase and anaphase.which is mainly used to control the division of cell.

One of the gene invovled in cell control is P53 gene which is a tumour suppressor gene.which is a regulatory gene where it controls the proliferation of cells upon activation and leads to cell death.

When the DNA is damaged ATM activates the CHK2 kinase then they both phosphorylate P53 which in activation release MDM2 which is binded to P53 .which acts as a factor for synthesis of p21 which later arrest the checkpoint.

During the mutation in these genes there is uncontrolled cell division which leads to cancer.

Cancer is mainly caused by Damage in DNA or by the exposure of carcinogens.for example: skin cancer they are caused due to the exposure of radiation and various pollutants.