Tag: biology

Rain, wind, ice and temperature changes break the tough, hard parent material or rocks. This process is very slow but it steadily continues. Such broken parts are further withered by same factors as well as some other factors as acids etc. Therefore, wind, water and the Sun are involved in soil formation. 

Polythene bags are not involved in soil formation. However, plastic bags are threat to environment, because these bags are non-degradable, i.e., do not decay and thus, do not lead to soil formation.

• Soil nature is described in pH values. It can be alkaline, acidic or neutral. 
• Highly acidic and highly saline soil often remains injurious for plant growth, microorganisms, etc. 
• Soil pH strongly affects microbial activities. Neutral or slightly acidic soil (5.5-6.5) remains best for the growth of the majority of plants.

Sir Alexander Fleming, a Scottish researcher, is credited with the discovery of penicillin in 1928.

In 1928, Alexander Fleming was investigating the properties of Staphylococci. One day, he observed that the culture of Staphylococci was contaminated with fungus and that colonies of the culture surrounding the fungus had been destroyed. 
Fleming grew the mold in a pure culture and found that it produce a substance that killed a number of disease-causing bacteria. He identified the mold (fungus) as being from the Penicillium genus and named the substance it released Penicillin. He investigated its positive antibacterial effect on many organisms and noticed that it affected bacteria such as Staphylococci and many other Gram-positive pathogens that cause scarlet fever, pneumonia, meningitis, diphtheria but not typhoid fever caused by Gram-negative bacteria.

Penicillin is a group of antibiotics derived from Penicillium fungi. The discovery of penicillin is attributed to Alexander Flemming in 1928.
Salman Waksman discovered streptomycin
Burkholder discovered Pfiesteria, which is a genus of heterotrophic dinoflagellates
Eugene Dubois was the first person to ever deliberately search for fossils of human ancestors
So, the correct answer is 'Fleming'

Selman Waksman, the microbiologist who discovered streptomycin, first used the word "antibiotic" in 1943. 

• Alexander Fleming was working on a Bacterial culture of Staphylococcus to studying the action of lysozyme and its role in the fighting of the infection.
• While he was working with the culture he noticed that the bacterial culture's growth is inhibited due to the growth of fungal infection on it.
• The fungus that infected the culture was  Penicillium notatum , whose secretion was later to be discovered as antibiotic penicillin.
  
• So the answer Penicillium notatum is correct.
  

• Alexander Fleming was working with a bacteria to study the action of lysozyme and its role in the fighting of the infection in the human body.
• The bacterial culture that he was working on was of Staphylococcus 
• Due to some fault, the bacterial culture Fleming was working on developed a fungal infection of Penicillium notatum which inhabited the growth of the bacteria in the culture.
• The secretion which was released by the fungus was called mold juice by Fleming but later he named it as penicillin after the name of the organism which secretes it.
• So the answer Staphylococcus is correct.