Biomedical science cell molecule interactions - Essay Example

This leads to the ras remaining in the active state, hence transmitting signals to the cell to continue its growth at a rapid rate in spite of the cell receptors being inactive. When several such ras oncogenes deregulate their functioning, then it leads to the development of cancer. The retinoblastoma tumour suppressor gene is present in chromosome 13 of the human beings. When the enzyme called Kinase, phosphorylates the product of retinoblastoma tumour suppressor gene, then it interacts with E2F protein.

E2F protein is involved in the replication of cells during the S phase of the cell cycle. This interaction stops the cell replication process. These genes cannot interrelate with E2F protein if it is not phosphorylated. A 2. Oncogenes are mutated forms of proto-oncogenes. Proto-oncogenes are involved in transmitting signals for the growth of the cells and anti-apoptotic pathways. Proto-oncogenes are converted to oncogenes either by point -mutation or chromosomal rearrangement. Although the functions of the oncogenes remain the same as that of proto-oncogenes, they are unable to respond to the normal regulatory signals.

Cells growth can be controlled either by inactivation of growth pathways or by the activation of apoptotic pathways. . Cells growth can be controlled either by inactivation of growth pathways or by the activation of apoptotic pathways. When these pathways are altered then it results in cancerous growth of cells. There are different methods by which oncogenes cause uncontrolled growth of cells resulting in cancer. They cause over-production of growth factors, lead to the activation of the cell receptors and increase the expression of proteins that inhibit apoptosis.

A single ontogene cannot cause cancer however when several such proto-oncogenes are mutated it results in cancerous growth of cells. The mutation of single oncogenes increases the probability of mutation of other proto-oncogenes and as a result, cancerous cells grow in an uncontrolled manner.Q3. Discuss the roles of nucleotides in cell signalling mechanisms.A3.A nucleotide consists of heterocyclic base, a sugar and one or more phosphate groups. They are fundamental for carrying out various cell signalling mechanism.

There are different types of nucleotides that help in carrying out these signalling mechanisms. The cyclic nucleotides such as cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) act as second messengers in cell signalling mechanism. They are located inside the cytosol cAMP is utilized to transfer the effects of hormones such as glucagons, adrenalin and luteinizing hormones. cGMP activates intracellular protein kinases in response to the peptide proteins to the external cell surface.

The hormones that are required to carry various functions of the cell cannot enter them directly through the cell membrane. Therefore, with the help of these nucleotides and enzymes such as adenylyl cyclase and guanylyl cyclase, signal are transferred inside the cell through a series of