Question

Bacteria were first discovered by
a. Robert Koch
b. L Pasteur
c. Robert Hooke
d. A.V Leeuwenhoek

Answer 1

Hint: Bacteria are the microorganisms which are first observed in the pond water. The structure of bacteria was discovered with the help of a compound microscope. Robert Hooke discovered the cell while Robert Koch discovered the disease causing bacteria. Bacteria are found in a wide variety.

Complete answer:
• Bacteria are the single-cell organisms. These are categorized into the category of the microorganism because of their small size. They can be found inside and outside of the body. They can survive in a wide range of environments.
• In 1670, bacteria were first discovered by Antony Van Leeuwenhoek. He observed many large bacteria while he was looking into pond water with his magnifying lens. Then he used a compound microscope to study the structure of these organisms.
• Robert Koch discovered bacteria that cause anthrax, tuberculosis, cholera, etc. He was not the first person who discovered bacteria.
• Louis Pasteur discovered the principles of vaccination, microbial fermentation, and pasteurization.
• Robert Hooke was first observed in the cells in the cork of the plant. He discovered plant cells and from his observation it was found that cells are the smallest units of life.

Hence, the correct answer is option (D).

Note: Bacteria have properties of eukaryotic cells such as cytoplasm, ribosomes, and a plasma membrane. Bacteria are mainly of two types: Archaebacteria or eubacteria. On the basis of the shapes, bacteria are classified into four groups: Spherical (cocci), rod (bacilli), spiral (spirilla), and comma (vibrios). They can be found as single cells, in pairs, chains or clusters. Bacteria can be good or bad for humans depending on their properties.