1. Samples of a microbial colony obtained from the natural environment are not pure culture. They are mixed cultures because the environment consists of an array of microorganisms and not one specific organism. A sample obtained from the natural environment such as water or soil may contain several species of microbes that need to be further isolated to obtain a pure culture.
2. Isolation streak plate technique involves the dilution of the sample several folds and then streaking a small amount using a sterile inoculation loop on an agar plate in a zig-zag manner. This is done to obtain a pure culture of bacteria from a mixed population by separating the microprocessor. When the sample is diluted into a small concentration and is streaked onto agar placed, widely spaced, discrete colonies of bacteria can be observed. These isolated colonies can be further cultured to obtain pure cultures by picking and re-streaking them on fresh agar plates.
3. A microbial colony is considered a pure culture because it consists of single species. A single species of bacteria cluster and form an isolated colony on an agar plate which can be further plated on fresh medium.
3-1 - If your agar plate shows discrete uncluttered colonies then you have obtained an isolated colony. The following picture might help you to understand.
3-2. If you subculture isolated microbes into a sterile nutrient broth without any contamination, it will still be considered pure culture because it is single isolated species in a sterile aseptic environment of the nutrient broth.
3.3. A pure culture can become a mixed culture due to contamination. This could be caused by airborne bacteria if your conditions are not aseptic. Contamination is possible if the work area is not clean and sterile or if the glassware is not sterile. The contamination can transform your pure culture into a mixed culture and is hence problematic. So, it is very important to maintain a sterile and aseptic environment, glassware, and instruments.
Learn more about subcultured at
brainly.com/question/26525141
#SPJ4
Answer:
1.4%
Explanation:
"At the PEAK of slavery in 1860, only 1.4% of Americans owned slaves. What your history books (don't) tell you is that 3,000 blacks owned a total of 20,000 slaves the same year." My source is: https://www.politifact.com/
Hope this helped you! Have a great day!
Answer:
higher literacy rates and good education leads to
productive workers leads to
higher wages leads to
investment in human capital leads to
higher standard of living
Explanation: Hope this helped a bit :)
The drug control policy that prevails in the Netherlands and Switzerland is "harm reduction".
Drug policy in Western Europe has dependably been test, yet, as of late, a few nations have joined the Netherlands and Switzerland in their quest for elective strategies for managing the drug epidemic. Numerous Western European countries are refocusing endeavors on the social welfare part of medication utilize and diminishing their emphasis on the law requirement reaction, while forcing stricter punishments on those associations that supply unlawful medications.
Explanation:
The examples of social practices of Nepal are:
1.Marriage
2.Brathabanda
3.Rice feeding(bhat khuai)
4.Funeral (kiriya), etc.
