#Question id: 40213
#Applied Microbiology
In the following question, a statement of Assertion (A) is followed by a statement of Reason (R).
Assertion (A): The annealing step must be performed at a significantly lower temperature than the denaturation step.
Reason (R): High temperatures destabilize hydrogen bonds, while lower temperatures favor the formation of hydrogen bonds required for primers to hybridize with the template.
#Question id: 40214
#Applied Microbiology
Which of the following represents the correct sequence of temperature changes during one single cycle of PCR amplification?
#Question id: 40215
#Environmental Science
Match the geological eons/events in List I with the biological milestones in List II.
| List I (Time Period/Event) | List II (Biological Milestone) |
| A. 4.0 - 3.8 Billion years ago | I. Appearance of first Eukaryotes |
| B. 3.5 Billion years ago | II. Oxygen Revolution (Great Oxidation Event) |
| C. 2.7 - 2.5 Billion years ago | III. Appearance of first cellular life (Prokaryotes) |
| D. 2.0 - 1.5 Billion years ago | IV. Formation of life precursors (RNA/Protocells) |
#Question id: 40216
#Environmental Science
#Question id: 40217
#Environmental Science
Consider the following statements about the Endosymbiotic Theory:
Statement I: It explains the origin of mitochondria and chloroplasts in eukaryotic cells.
Statement II: Mitochondria and chloroplasts have their own circular DNA, similar to bacteria.
Statement III: The theory proposes that these organelles originated as free-living prokaryotes that were engulfed by a host cell.
#Question id: 40218
#Environmental Science
Match the concepts/experiments in List I with the scientists in List II.
| List I (Concept/Experiment) | List II (Scientist) |
| A. Hot Dilute Soup (Prebiotic Soup) | I. Francesco Redi |
| B. Panspermia (Cosmozoic Theory) | II. J.B.S. Haldane |
| C. Maggots in decaying meat experiment | III. Richter & Arrhenius |
| D. Omne vivum ex vivo (Biogenesis) | IV. Louis Pasteur |