0
How would you determine whether a colony was a contaminant on a streak plate?
Wiki User
∙ 7y ago
One to determine whether a colony on a streak plate is a contaminant is by observing whether it is located along the streak lines. Another is to compare the size, shape, texture and color of the colony against an uncontaminated sample to see if it matches previous ones. Anything growing beyond streak lines and outside of the expected pattern of growth is an obvious contaminant.
Alfonso Mills
Wiki User
∙ 13y agoThe contaminant colony will vary in shape, so the appearance of colonies can be used to distinguish different bacteria.
Wiki User
∙ 12y agothe contaminants will look different than the rest of the colonies which are pure or the target ones on the streak plate.
Wiki User
∙ 11y agoColor would be one way. E. coli are an off white color and contaminants, whether other bacteria or fungi, would show up markedly well in color variation.
Wiki User
∙ 11y agoThere will be dirt and it will look fuzzy
Add your answer:
Earn +20 pts
If an inoculated plate had colonies between the streak lines what would you conclude?
It depends, if there is no growth or colony appearance on streak line and only it shows growth in b/w the streak line then it is certainly a contamination and if there are colonies on streak line and not ressemble with the streak culture then also it is a contamination but there can be a chance that colony appears due to some fault in streaking procedure and the inoculum drops between the streak line so it depends.
What type of culture technique would be used to obtain a pure culture?
Streak plating and picking a single colony for the culturing in a broth.
How could you tell if one of the colonies on the plate was a contaminant that fell in from the air?
If one of the colonies was to be contaminated by something in air, you would be able to tell by there being a difference in look for specimen. Also looking to see if something is growing on top of smooth specimen.
When would a microbiologist want to use the streak-to-grow method.?
Plate streaking is often done to isolate a colony of bacteria. For instance, if a broth was grown with 2 or 3 different types of bacteria, it could be streaked out in a "3-phase streak." In a 3-phase streak the initial streak takes up a very small area (we draw a T on the back of the plate, this streak goes in the section above the T). The loop is flamed to kill off any bacteria still on it, then a couple streaks are made out of the original. This grabs some of the bacteria from that concentrated streak and spreads them out. This is repeated once more until the final streaks are less and less concentrated bacteria. When we incubate the plate we'll find lots of growth where the original streak was and less and less as we follow the path of the 3-phases. What you're looking for now is a single colony, off by itself. This can then be scraped off and plated on a separate plate and considered a "pure colony." Another usual time to use streak-to-grow bacteria is when you want to know the quantity or concentration of bacteria. You take maybe 0.1mL of solution and plate it, then count the number of colonies that form. Say you have 56 colonies, now you can say: 56 cfu (colony forming units) -------- 0.1 mL or 560 cfu/mL This is usual when testing to see whether a sterilization technique worked, or if a product is within the regulated levels of bacteria to be released the public, etc etc.
What advantage does the streak plate method have over the pour plate method?
A disadvantage of the streak plate technique could be colony isolation problems. If the streaking technique is not done properly or if there is too much of an organism present on the inoculating loop then the cells can cluster and form what looks like one colony but it can actually be a couple colonies (made from a couple cells). This can cause an inaccurate colony forming unit count.
How do you determine the streak of a mineral and why is streak a useful property?
you see and feel how shiney it is
How do you determine the streak of a mineral whose Mohs scale is higher than the streak plate?
You can determine the streak of a mineral whose Mohs scale is higher than the streak plate by either filing or crushing with a hammer before rubbing the sample on a streak plate.
How do you determine minerals streak?
The color of a mineral in powdered form is called the mineral's Streak
What properties to would you use to determine whether to mineral samples are different minerals?
You could use the streak color, whether it has cleavage or fracture, the texture, the luster, the hardness, the color, and lots of different properties.
What properties would you use to determine whether two minerals are different minerals?
You could use the streak color, whether it has cleavage or fracture, the texture, the luster, the hardness, the color, and lots of different properties.
What properties would use to determine whether two mineral samples are different minerals?
You could use the streak color, whether it has cleavage or fracture, the texture, the luster, the hardness, the color, and lots of different properties.
If an inoculated plate had colonies between the streak lines what would you conclude?
It depends, if there is no growth or colony appearance on streak line and only it shows growth in b/w the streak line then it is certainly a contamination and if there are colonies on streak line and not ressemble with the streak culture then also it is a contamination but there can be a chance that colony appears due to some fault in streaking procedure and the inoculum drops between the streak line so it depends.
What is the purpose of the plate?
A streak plate is used to determine the streak colour of a mineral. You take the mineral and scratch it against the streak plate, and it will create a coloured streak on the plate. The streak is not always the same colour as the mineral itself.
Why could the streak of corundum be difficult to determine?
The mineral corundum, with a Mohs hardness of 9, will be harder than a ceramic streak plate and therefore leave no streak.
Why is streak an important physical property of minerals?
A streak test is used to determine a minerals streak color. This can help in the identification of minerals.
How you differentiate between Transformed bacterial colonies and satellite colonies?
Re-streak the center of the 'star' colony (transformed surrounded by satellites) on a plate contains the antibiotic, typically ampicillin. The colonies in the tertiary streak will most likely be the transformants. If you want to be quite sure, pick a single colony from the tertiary streak and re-streak again on a plate containing the antibiotic.
What test do geologists use to determine the hardness of a mineral?
the streak test
