This set of Class 12 Biology Chapter 8 Multiple Choice Questions & Answers (MCQs) focuses on “Causes of Cancer”.
1. Which of the following property is not exhibited by a cancerous cell?
a) No contact inhibition
b) Limited life span
c) Abnormal shape and size
d) Uncontrolled division of cells
Explanation: Cancerous cells show uncontrolled and abnormal division. They do not show the property of contact inhibition. They have abnormal shape and size and show an unlimited life span.
2. When is World Cancer Day celebrated?
a) 1st December
b) 31st October
c) 4th February
d) 12th August
Explanation: World Cancer Day is celebrated on 4th February to create awareness amongst people regarding the most fatal and non-communicable disease. Cancer is one of the most dreaded diseases of human beings and is a major cause of death all over the globe.
3. Which of the following is not true regarding neoplasm?
a) Abnormal tissue
b) Caused by abnormal proliferation of cells
c) Cannot spread to other body organs
d) Responsible for the formation of tumour
Explanation: Neoplasm is a new abnormal tissue that is capable of continued growth, the formation of tumour, crowding and disrupting of normal cells. They are caused by abnormal proliferation of the cells. They may or may not be localised.
4. Which of the following is a localised tumour surrounded by connective tissue?
a) Benign tumour
b) Malignant tumour
d) Abnormal cells
Explanation: Benign tumour is a large localised mass of abnormal tissue which presses other tissues and causes pain but does not infiltrate adjacent tissues because it is encapsulated in connective tissue.
5. How does cancer spread from one infected individual to another?
a) By touching
b) By kissing
c) By hugging
d) Cannot spread
Explanation: Cancer cannot spread from one infected individual to another because it is a non-communicable disease. Though, the genes which cause cancer can be inherited by children from their parents.
6. More than a million Indians die from cancer annually.
Explanation: Cancer is one of the most dreaded diseases. More than a million Indians suffer from cancer and a large number of them die annually. The mechanisms that underlie the development of cancer or oncogenic transformation of cells, its treatment and control have been some of the most intense areas of research in biology and medicine.
7. How do cancerous cells spread from one body organ to another?
a) Through hormones
b) Through water
c) Through Viruses
d) Through blood
Explanation: Cancerous cells spread from one body organ to another through blood, lymph or through the secondary growth of the malignant tumour.
8. Which of the following statement is incorrect regarding malignant tumour?
a) It is a large mass of abnormal tissue
b) It is encapsulated
c) It invades adjacent tissues
d) It reaches distant sites
Explanation: Malignant tumours are a mass of proliferating cells called neoplastic or tumour cells. These cells are not encapsulated. They grow very rapidly, invading and damaging the surrounding normal tissues. Cells sloughed from such tumours reach distant sites through the blood.
9. Which of the following is the most feared property of malignant tumours?
b) Contact Inhibition
Explanation: The most feared property of malignant tumours is a metastasis. Cells sloughed from malignant tumours reach distant sites through blood, and wherever they get lodged in the body, they start a new tumour there. This property is called metastasis.
10. The agents causing cancer are known as __________
Explanation: Transformation of normal cells into cancerous neoplastic cells may be induced by physical, chemical or biological agents. These agents are called carcinogens.
11. Proto-oncogenes are responsible for the lysis of cancerous cells.
Explanation: Proto-oncogenes are not responsible for the lysis of cancerous cells. Instead, several genes called cellular oncogenes (c-onc) or proto-oncogenes have been identified in normal cells which when activated under certain conditions, could lead to oncogenic transformation of cells.
12. Which of the following is not a chemical carcinogen?
Explanation: Heat is a physical carcinogen. Chemical carcinogens often include environmental pollutants which cause cancer. For example, soot, coal tar, cigarette smoke, cadmium oxide, aflatoxin, asbestos, artificial sweeteners etc.
13. Which of the following genes on activation produces malignant neoplasm?
a) Pleiotropic genes
b) Multiple genes
d) Neonatal genes
Explanation: Oncogenes on activation produces malignant neoplasm. Cancer-causing viruses called as oncogenic viruses have genes called viral oncogenes which when activated under certain conditions, produces malignant neoplasm.
14. Which of the following is not a biological agent that causes cancer?
b) HPV (Human Papilloma Virus)
c) HCV (Hepatitis B and C viruses)
d) Epstein-Bar virus
Explanation: Trauma is a Physical agent that causes cancer. The biological carcinogens include Human Papilloma Virus, Hepatitis B and C viruses and Epstein-Bar virus which cause Cervical cancer, Liver cancer and Burkitt’s lymphoma respectively.
15. Which of the following given physical carcinogens is non-ionising by nature?
c) Gamma Rays
d) UV rays
Explanation: UV rays are non-ionising physical carcinogens. X-rays and Gamma Rays are ionising physical carcinogens. Skin cancers are more common in areas with a higher incidence of UV radiations.
Sanfoundry Global Education & Learning Series – Biology – Class 12.
To practice all chapters and topics of class 12 Biology, here is complete set of 1000+ Multiple Choice Questions and Answers.
- Get Free Certificate of Merit in Biology - Class 12
- Participate in Biology - Class 12 Certification Contest
- Become a Top Ranker in Biology - Class 12
- Take Biology - Class 12 Tests
- Chapterwise Practice Tests: Chapter 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
- Chapterwise Mock Tests: Chapter 1, 2, 3, 4, 5, 6, 7, 8, 9, 10