The Miller-Urey experiment simulated the primitive Earth's atmosphere. The mixture of gases used in the experiment was: MCQ with Answer and Explanation
The Miller-Urey experiment simulated the primitive Earth's atmosphere. The mixture of gases used in the experiment was:
A. CO2, NH3, H2O, and O2
B. CO2, N2, H2O, and O2
C. CH4, NH3, H2, and H2O (vapor)
D. CH4, CO2, N2, and H2O
Answer: Option C
Solution (By JKExamLibrary)
In 1953, Stanley Miller and Harold Urey conducted an experiment to test the Oparin-Haldane hypothesis of chemical evolution. They simulated the reducing atmosphere of primitive Earth, which they believed lacked free oxygen. The gas mixture used was methane (CH4), ammonia (NH3), hydrogen (H2), and water vapor (H2O). By applying electrical sparks (simulating lightning), they successfully synthesized amino acids and other organic compounds.
Explanation:
Bryophytes are non-vascular land plants that include mosses, liverworts, and hornworts. Funaria is a common moss and a classic example of a bryophyte. Spirogyra is a green alga, ferns are pteridophytes (vascular cryptogams), and Pinus is a gymnosperm.
Consider statements about human diseases: 1. Cholera is a bacterial disease. 2. Polio is a viral disease. 3. Malaria is transmitted by a mosquito. Which are correct?
Explanation:
Cholera is an acute diarrheal illness caused by the bacterium Vibrio cholerae, typically transmitted through contaminated water. Polio (poliomyelitis) is a highly infectious viral disease caused by the poliovirus, which can lead to paralysis. Malaria is a life-threatening disease caused by Plasmodium parasites, which are transmitted to humans through the bites of infected female Anopheles mosquitoes. All three statements are correct.
Explanation:
Smooth endoplasmic reticulum (SER) lacks ribosomes and is involved in lipid and steroid hormone synthesis, carbohydrate metabolism, and detoxification of drugs and poisons (via cytochrome P450 enzymes). Rough ER synthesizes proteins. Golgi modifies/packages. Lysosomes digest. Liver cells have abundant SER. SER also sequesters Ca²⁺ ions in muscle cells (sarcoplasmic reticulum).
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