Viva Questions of Xenobiotics and Carcinogenesis

Correlation:

Q: Define detoxification. Mention its site. (Topic: Xenobiotics)

A: Biochemical reactions occurring in the body to convert foreign (often toxic) compound to non-toxic or less toxic and more easily excretable forms. It occurs in liver.

 

Q: Name the phase II reaction in Detoxification. Name its agents. (Topic: Xenobiotics)

A: Conjugation Reactions

Conjugating agents: Glycine, Glutathione, Glucuronic Acid, Sulfation, acetylation, Methylation

Q: Mention the role of glycine as conjugating agent in detoxification for bile acids. (Topic: Lipids)

A: As a part of normal body metabolism, glycine conjugates bile acids.

Cholic acid   →   Glycocholic acid

Chenodeoxy cholic acid →      Glyco-chenodeoxy cholic acid

Q: Mention the role of glycine as conjugating agent for detoxification in liver. (Topic: Organ function Tests)

A:  Glycine + Benzoic acid → Hippuric acid

Q: Mention the role of glucuronic acid as conjugating agent for bilirubin (Topic: Hemoglobin)

A:                                                      UDP Glucuronyl transferase

UDP-Glucuronate + Bilirubin                         →                               Bilirubin diglucuronide

(Conjugated bilirubin)

Q: What is Glutathione? (Topic: Amino Acids & Proteins)

A: Tripeptide; γ-glutamyl-cysteinyl-glycine

 

Q: Mention the Phase I reactions in detoxification. (Topic: Xenobiotics)

A:  Oxidation, Reduction and Hydrolysis

Q: Mention how alcohols, aldehydes and amines are detoxified? (Topic: Xenobiotics)

A: By Phase I reaction- Oxidation

 

Correlation:

Q: Define tumor markers. (Topic: Oncogenesis)

A: Biochemical indicators employed to detect the presence of cancers.

Q: Mention the proteins and antigens which can be used as tumor markers along with associated Cancers. (Topic: Amino Acids & Proteins)

 

Tumor Markers Associated cancers
Alpha fetoprotein (AFP) Cancers of the liver, germ cell cancers
Carcinoembryonic antigen (CEA) Cancers of colon, lung, breast
CA-125 Ovarian cancer
Prostate specific antigen (PSA) Prostate cancer

 

Q: Mention enzymes which can be used as tumor markers. (Topic: Enzymes)

A: Enzymes: PAP, NSE, Alkaline phosphatase

Q: Mention hormones which can be used as tumor markers. (Topic: Oncogenesis)

A: Hormones: hCG, Calcitonin, Catecholamines

Q: Mention competitive enzyme inhibitor, which can be used as an anticancer drug. (Topic: Enzymes)

A: Methotrexate which competitively inhibits enzyme Dihydrofolate reductase

Q: Mention the enzyme used in cancer therapy. (Topic: Enzymes)

A: Asparginase used in Cancer therapy- leukemia (ALL)

Q: Mention effect of cancer on nitrogen balance. (Topic: Nutrition)

A: Negative nitrogen balance

Q: Mention use of polymerase chain reaction in cancer detection. (Topic: Recombinant DNA Technology)

A: Identification of mutations in oncosupressor genes, such as p53, retinoblastoma gene and so on help in identifying individuals vulnerable to cancer.

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