MCQ
Q.
Who discovered bacteria?
Correct Answer: D
The correct answer is Leeuwenhoek.
Key Points
| Discoverer | Discovery |
| Fleming | Penicillin |
| Hans and Zacharias Janssen | Microscope |
| Temin | Reverse transcriptase |
| Leeuwenhoek | Bacteria |
Additional Information
- Penicillin:
- Penicillin is one of the first and still one of the most widely used antibiotic agents, derived from the Penicillium mold.
- In 1928 Scottish bacteriologist Alexander Fleming first observed that colonies of the bacterium Staphylococcus aureus failed to grow in those areas of a culture that had been accidentally contaminated by the green mold Penicillium notatum.
- He isolated the mold, grew it in a fluid medium, and found that it produced a substance capable of killing many of the common bacteria that infect humans.
- Australian pathologist Howard Florey and British biochemist Ernst Boris Chain isolated and purified penicillin in the late 1930s, and by 1941 an injectable form of the drug was available for therapeutic use.
- Microscope:
- Microscope is an instrument that produces enlarged images of small objects, allowing the observer an exceedingly close view of minute structures at a scale convenient for examination and analysis.
- Although optical microscopes are the subject of this article, an image may also be enlarged by many other waveforms, including acoustic, X-ray, or electron beam, and be received by direct or digital imaging or by a combination of these methods.
- The microscope may provide a dynamic image (as with conventional optical instruments) or one that is static (as with conventional scanning electron microscopes).
- Reverse transcriptase:
- Reverse transcriptase also called RNA-directed DNA polymerase, an enzyme encoded from the genetic material of retroviruses that catalyzes the transcription of retrovirus RNA (ribonucleic acid) into DNA (deoxyribonucleic acid).
- This catalyzed transcription is the reverse process of normal cellular transcription of DNA into RNA, hence the names reverse transcriptase and retrovirus.
- Reverse transcriptase is central to the infectious nature of retroviruses, several of which cause disease in humans, including human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS), and human T-cell lymphotropic virus I (HTLV-I), which causes leukemia.
- Bacteria:
- Bacteria, singular bacterium, any of a group of microscopic single-celled organisms that live in enormous numbers in almost every environment on Earth, from deep-sea vents to deep below Earth’s surface to the digestive tracts of humans.
- Bacteria lack a membrane-bound nucleus and other internal structures and are therefore ranked among the unicellular life-forms called prokaryotes.
- Prokaryotes are the dominant living creatures on Earth, having been present for perhaps three-quarters of Earth history and having adapted to almost all available ecological habitats.
- As a group, they display exceedingly diverse metabolic capabilities and can use almost any organic compound, and some inorganic compounds, as a food source.
