What is the primary use of the following agar slant agar deep broth?
What is the primary use of slants? Provides a solid growth area that is easier to store. What is the primary use of deeps? Used to grow bacteria that needs less oxygen.
What are agar deep used for?
Agar deeps are used to grow bacteria that require LESS oxygen then is present on the surface of the medium. They also aid in determining oxygen requirements and motility of bacteria. Motile bacteria will grow/ move away from the point of inoculation.
What is the difference between agar slants and deep Agar?
If the medium in the test tube is allowed to harden in a slanted position, the tube is designated an agar slant; if the tube is allowed to harden in an upright position, the tube is designated an agar deep tube; and if the agar is poured into a Petri dish, the plate is designated an agar plate.
What would you use to inoculate an agar deep?
An Agar Deep Stab is a tube filled with a solid medium containing agar. It is inoculated with a needle to observe the growth patterns in the agar.
What tool is inoculate agar deep?
straight needle
Why is it important to use a loop rather than a needle to inoculate an agar plate?
It is important to use a needle rather than an inoculating loop because the needleis used to transfer the specimen to the soft agar medium. The inoculating loop isused to transfer specimens in a liquid medium or plating. Using the needle willcreate more growth to occur along the stab line.
What are slant cultures used for?
Agar slants are commonly used to generate stocks of bacteria. Agar plates can be used to separate mixtures of bacteria and to observe colony characteristics of different species of bacteria (you will perform an experiment in this lab to illustrate this).
How do you make nutrient agar slants?
Nutrient Agar Slants: Prepare a nutrient agar medium and boil it with stirring until all the agar is melted. You must stir this very well so that the melted agar is distributed throughout the medium. 3. Use a pipette to transfer about 5 ml of molten agar to each test tube.
How long do agar slants last?
2 months
What are the ingredients found in nutrient agar?
Nutrient Agar is composed of pancreatic digest of gelatin and beef extract, which provide organic nitrogen compounds, long-chained fatty acids, carbohydrates, vitamins, and essential amino acids necessary for cell growth.
What is in an agar plate?
An agar plate is a Petri dish that contains a growth medium solidified with agar, used to culture microorganisms. Sometimes selective compounds are added to influence growth, such as antibiotics.
What bacteria Cannot grow on nutrient agar?
Some bacteria cannot be grown with nutrient agar medium. Fastidious organisms (picky bacteria) may need a very specific food source not provided in nutrient agar. One example of a fastidious organism is Treponema pallidum, bacteria that causes syphilis.
What are the different types of agar plates?
Types of Agar Plates
- Blood Agar Plates. Blood agar plates (BAP) are made by adding five to ten percent sheep or horse blood to the nutrient medium.
- Nutrient Agar Plates. Nutrient agar grows the largest variety of microbes, typically fungi and bacteria.
- MacConkey Agar Plates.
- Other Kinds of Agar Plates.
How can you tell if a plate is contaminated in agar?
If the plate has not been inoculated, the presence of any bacterial colonies indicates contamination. On an inoculated plate, look for colonies that display morphology different than what you would expect from the type of bacteria used to inoculate the plate.
How long does it take for bacteria to grow on agar plate?
If you do not have an incubator, you can keep the Petri dish at room temperature, but it may take longer for the bacterial colonies to form. After 24 to 48 hours, remove the petri dish from the incubator and examine the growth of the bacterial colonies.
How do you identify bacteria on agar?
Colony morphology is a method that scientists use to describe the characteristics of an individual colony of bacteria growing on agar in a Petri dish. It can be used to help to identify them. A swab from a bin spread directly onto nutrient agar. Colonies differ in their shape, size, colour and texture.
Why do you have to boil the agar solution before dispensing it into plates and tubes?
Why do you have to boil the agar solution BEFORE dispensing it into tubes? To make sure everything is dissolved and evenly distributed. At what temperature does agar solidify? How is air contamination prevented when an inoculating loop is used to introduce or take a bacterial sample to/from an agar plate?
Why do we need to cover the culture medium?
Culture media is of fundamental importance for most microbiological tests: to obtain pure cultures, to grow and count microbial cells, and to cultivate and select microorganisms. A microbiological culture medium is a substance that encourages the growth, support, and survival of microorganisms.
What is the best way to dissolve agar in a medium as you are preparing it?
What is the best way to dissolve agar in a medium as you are preparing it? It is solid at room temperature, but liquid at temperatures that are tolerated by bacteria. Why is agar a useful solidifying agent in microbiology? Add several drops of HCl and recheck the pH.
Which method is usually used to sterilize most agar media?
autoclave to sterilize the tube media. autoclave the agar medium for plate production and then pour into sterile petri dishes.
Why does agar need to be boiled?
To dissolve them, you need to heat the solution first. Agar just happens to be the most dramatic because it won’t dissolve at all until you reach temperatures of about 90° C. Technically you don’t actually need to boil it, but it’s easier to just boil than it is to try to hold it slightly below boiling.
What is the difference between Agar and broth?
The only difference between broth and agar media is that broths do not contain an agar component. We use broth tubes primarily for specific assays, or (rarely) for bacteria that will not form colonies on a solid surface. Unlike preparation of agar plates, tubes are prepared with media already in the incubation vessel.
Why do you have to boil agar before you can place it in the autoclave?
BOILING MEDIA PRIOR TO AUTOCLAVING It is necessary to ensure that the powder is properly dissolved so that agar is distributed uniformly throughout the medium and to minimise the risk of post-sterilisation contamination which may occur if dry powder remains above the level of the water.
Why should you always mix up a broth culture before using it for the first time?
Bacterial liquid cultures should be shaken always (but not too vigorously), in order to ensure aeration and oxygen and nutrient availability as well as to avoid bacterial settlement on the flask bottom which would result in cell death from the lack of nutrient availability.
What is nutrient agar used for?
Nutrient Agar is used for the cultivation of bacteria and for the enumeration of organisms in water, sewage, feces and other materials. Early in the 20th century, the American Public Health Associa- tion published the formula for a general purpose medium for the growth of a wide variety of nonfastidious microorganisms.