The technique of separating molecules based on their size and charge is:
A. Spectrophotometry
B. Centrifugation
C. Chromatography
D. Electrophoresis
Answer: Option D
Solution (By JKSSB Mock Tests)
Gel electrophoresis, especially agarose gel electrophoresis, separates DNA, RNA, or protein fragments based on size and charge under an electric field. Smaller fragments move faster through the gel matrix. Centrifugation separates by density, chromatography by differential partitioning, spectrophotometry measures light absorption. Electrophoresis is a fundamental tool in molecular biology.
Consider statements about human diseases: 1. Typhoid is caused by a bacterium. 2. Malaria is caused by a protozoan. 3. Dengue is caused by a virus. Which are correct?
Explanation:
Typhoid fever is a systemic bacterial infection caused by Salmonella enterica serotype Typhi, transmitted through contaminated food and water. Malaria is a life-threatening disease caused by protozoan parasites of the genus Plasmodium (like P. falciparum), transmitted by Anopheles mosquitoes. Dengue fever is a viral infection caused by the Dengue virus (a flavivirus), transmitted by Aedes mosquitoes. All three statements correctly identify the causative agents of these major diseases.
Explanation:
Vitamin K-dependent carboxylation allows prothrombin and other clotting factors to bind calcium and participate in coagulation. Deficiency prolongs clotting time.
Explanation:
Salivary amylase (ptyalin) hydrolyzes starch into maltose and dextrins in the mouth. It functions optimally at neutral to slightly alkaline pH. Pepsin digests proteins in the stomach, lipase digests fats, trypsin is a pancreatic protease. Salivary amylase action ceases in the acidic stomach.
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