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
That they couldn't represent anything and they wanted to destroy any icons
Answer: inattentional blindness
Explanation:
This refers to how we tend to zoom out of everything around us and zoom in to what seems important to us at that particular moment trusting that our schemas will assist us with other things.
Since our cognitive and processing ability is limited it gives us sufficient time to focus our utmost attention to what matters more at that time.
Sometimes this happen because we don't expect certain things to happen in certain situation like standing in a checkout you are not really expecting that someone may be robbing a person just in day light.
Answer:
B
Explanation:
Hans Selye is regarded as the founder of the theory of stress.
He developed the general adaptation syndrome (GAS) which describes how the body reacts to stress.
The stages of GAS are :
alarm reaction - flight or fight response to stress
resistance - continued exposure to stress leads to higher metabolic response to offset the stress
exhaustion - continued exposure to stress can negatively affect the body and lead to health problems
Hans made this discovery in the 1930s after studying the response of rats after the injection of hormones into them. He compared their cortisol and blood sugar levels in rats before and during the experiment.
He concluded that it was the stress that caused the rat to become ill and die
Answer:
The Missouri Compromise was struck down as unconstitutional, and slavery and anti-slavery proponents rushed into the territory to vote in favor or against the practice. The rush, effectively led to massacre known as Bleeding Kansas and propelled itself into the very real beginnings of the American Civil War
