Notify me of followup comments via e-mail. Skip to content. Agar vs. February 16, February 16, Term details. Enzymes are usually proteins e. They bind to specific substrate s and provide the optimal conditions in their "active site" for a reaction to occur. So, after they help out with some reaction, they can do it again and again and again. I say "help out" because the enzyme doesn't really "do" anything - it can only help make something that was "possible," "likely.
Instead, enzymes lower the activation energy required to get the reaction going. The Chemical Composition of Nutrient Agar. Five Steps to Prepare Agar Slants. What Are Agar Slants?
Isolation Techniques for a Streak Plate. Technique to Separate Bacteria in a Mixed Culture. How to Make a Bacterial Flowchart. Characteristics of Salmonella Bacteria. Different Agar Plates. Types of Spore Forming Bacteria. If the salt concentration is not similar, osmosis takes place transporting excess water into or out from the cell. Surface growth of Escherichia coli cells on a membrane filter placed on a nutrient agar plate under various conditions was studied with a mathematical model.
The surface growth of bacterial cells showed a sigmoidal curve with time on a semilogarithmic plot. They appear large, circular, low convex, grayish, white, moist, smooth and opaque. MacConkey Agar MAC is a selective and differential medium designed to isolate and differentiate enterics based on their ability to ferment lactose.
Bile salts and crystal violet inhibit the growth of Gram positive organisms. Lactose provides a source of fermentable carbohydrate, allowing for differentiation. Nutrient agar is a general purpose medium supporting growth of a wide range of non-fastidious organisms.
It is relatively toxic to humans, and some people have allergic reactions to it. If it is not taken with enough water, agar can swell and block the esophagus or bowel. In some people, agar may also raise cholesterol. Health Benefits Agar has no calories, no carbs, no sugar, not fat and is loaded with fiber. It's free from starch, soy, corn, gluten, yeast, wheat, milk, egg and preservatives.
It absorbs glucose in the stomach, passes through digestive system quickly and inhibits the body from retaining and storing excess fat.
Types of agar plates[edit] Blood agar - contains blood cells from an animal e. Chocolate agar - this contains lysed blood cells, and is used for growing fastidious fussy respiratory bacteria. Neomycin agar - contains the antibiotic neomycin. Sabouraud agar - used for fungi.
Streptococcus pyogenes , S. Tryptic Soy Agar - uninoculated. Tryptic Soy Agar - Escherichia coli. Tryptic Soy Agar - Pseudomonas aeruginosa Note the blue-green color due to pyocin production by the bacteria.
Chocolate Agar. Chocolate Agar - uninoculated. Purpose: Cultivation of fastidious organisms such as Neisseria or Haemophilus sp. Chocolate Agar - Staphylococcus aureus Note: luxuriant growth with yellow pigmented colonies.
Chocolate Agar - Neisseria gonorrhoeae Note: small colonies that appear transparent on close examination. Chocolate Agar - Escherichia coli Note: luxuriant growth of gray-white colonies. Thayer-Martin Agar. Thayer-Martin Agar - uninoculated. Type: Enriched and selective; contains antibiotics colistin kills gram-negative coliforms , vancomycin kills gram-positives , nystatin kills fungi.
Purpose: To select for fastidious organisms, such as N. Thayer-Martin Agar - Staphylococcus aureus Note: vancomycin in the medium inhibits the growth of staphylococci. Thayer-Martin Agar - Neisseria gonorrhoeae Note: luxuriant growth of this fastidious bacterium.
Thayer-Martin Agar - Escherichia coli Note: colistin in the media inhibits the growth of enterics.
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