Tag: non-infectious diseases

PCBs (polychlorinated biphenyls) and dioxins are persistent organic pollutants known to be carcinogenic. They accumulate in the food chain and are linked to various types of cancer.

• HeLa cells are the cell type in immortal cell lines used in scientific research. It is the oldest and most commonly used human cell line.
• The line was derived from cervical cancer cells taken on February 8, 1951, from Henrietta Lacks, a patient who died of her cancer on October 4, 1951.  These cells are grown in a laboratory and are used for conducting many experiments.

Cancer is a group of diseases involving the abnormal cell growth where there is invasion of the local tissue and there is a potential to invade or spread to other body parts .
Therefore, the correct answer is option D.

During tumorigenesis, cancerous cells undergo rapid cell division and compete with normal cells for nutrients.
Cancer cells spread to other parts of the body, a process called metastastize i.e., are not confined in area  of formation.
Cancer is the result of cells that uncontrollably grow and do not die.
So, statements A, B and C are correct.
Normal cells when grown in culture, will become growth inhibited, when they encounter another cell. This is contact inhibition and Cancer cells show no contact inhibition as they do not stop dividing and keep growing.
Thus, the correct answer is option (D), 'They show contact inhibition'.

Metastasis is the movement of spreading of cancer cells from one organ or tissue to another. Cancer cells usually spread through the blood or the lymph system. It is mainly caused due to the mutagens which cause a sudden heritable change in the DNA content which leads to fatal abnormalities.
So, the correct answer is option B.

Genes are found in the DNA of every cell of the human body. The functions of the cell, its growth pattern, divisions and life are all determined and control by the genes. Cancers in the human body are the result of mutations or changes in one or more genes in a cell leading to an abnormal protein or no protein at all. An abnormal protein in the cells causes them  to multiply uncontrollably and become cancerous. Any alteration in the tumour suppressor gene may result in cancer. 

Cancer cells are cells that divide rapidly, forming solid tumours or flooding the blood with abnormal cells. Malignant cancerous cells spread from their initial site to other organs or tissues resulting in metastasis. Cancer cells undergo invasion of local tissue i.e., direct extension and penetration by cancer cells into neighbouring tissues. Hence, cancer cells are characterised by uncontrolled growth, spreading to other body part and invasion of local tissue.

• A gene is the basic physical and functional unit of heredity. Genes are made up of DNA and DNA is present inside the nucleus.
• Mutations in genes can cause cancer by accelerating cell division rates or inhibiting normal controls on the system, such as cell cycle arrest or programmed cell death. As a mass of cancerous cells grows, it can develop into a tumour.
• Hence Transformation of a normal cell to cancer cell may start with changes in  Nucleus.
  
• So, the correct answer is 'Nucleus'.