Vocabulary
1. Inoculum: a material used for inoculation.
2. Loop (the tool): A wire made into a loop to assist in picking up inoculum from a culture of microorganisms. The loop is also used in the process of cultivating microbes by transferring inoculum for streaking.
3. Agar vs Blood Agar:
a. Agar: a growth medium made with agar and other nutrients. The agar allows microorganisms such as fungi and bacteria to be cultured.
b. Blood Agar: Blood agar is used for the purpose of cultivation and isolation of various strains of pathogenic bacteria.
4. Fastidious Bacteria: A microorganism with a unique nutritional need and will only grow when specific nutrients are included in its feed.
5. Hemolytic: The breakdown of red blood cells and the ability of bacteria colonies to induce hemolysis when it is grown on blood agar. This allows process allows for the process of classifying organisms. 6. Alpha, Beta, Gamma Hemolysis: a. Alpha: A color change occurs where initially it is red and then turns to a very dark green as a result of oxidation of hemoglobin to methemoglobin by hydrogen peroxide. b. Beta: Complete lysis of blood cells. It is presented as a yellowish color on the blood agar medium. This hemolysis happens because of an enzyme produced by a bacterium called streptolysin. c. Gamma: These organisms are known as nonhemolytic and are distinguished based of lack of color change or transparency to the medium under the bacteria colonies. 7. Colony morphology: The morphology (study of the form and structure of living things) of cellular colonies grown in cultures and how different types of bacteria types look growing on agar. Questions 1. Why do we grow bacteria on agar? What is the purpose of this lab test? a. We grow bacteria on agar because it is a controlled environment that is used to culture microorganisms. Because Agar is flexible media with its capability of being in solid/semi solid state, this allow the microbial colonies to grown on the surface by allowing them to grow on a better surface so that the microbial colonies …show more content…
Why do we fire the loop before the streaking process?
a. We fire the loop before the streaking process to ensure that all microbial cells are burned off from the loop so that it does not cause contamination of the culture.
3. How do we get the sample onto the loop?
a. After sterilizing the loop over an open flame, depending if the bacteria is in a liquid or solid form, we dip the loop inside the sample test tube and dip the inoculated loop straight down in the tube. If the sample is a solid the sterilized loop should barely touch the culture.
4. Why do we have to wait for the loop to cool before collecting a sample?
a. We have to wait for the loop to cool before collecting samples because we may kill the bacteria or melt the agar jelly that is going to be in contact with the bacteria.
5. What do you do to the loop in between streak patterns (on the same plate)?
a. After your first streak pattern you should flame the loop again and let it cool. Then you follow the same procedure of lifting the Petri plate, streaking it across the first streak pattern onto the second quadrant of the plate, flame the loop again, etc.
6. How much of the plate do we cover with the primary inoculum?
a. We should cover between a quarter and third of the plate in total
1. Inoculum: a material used for inoculation.
2. Loop (the tool): A wire made into a loop to assist in picking up inoculum from a culture of microorganisms. The loop is also used in the process of cultivating microbes by transferring inoculum for streaking.
3. Agar vs Blood Agar:
a. Agar: a growth medium made with agar and other nutrients. The agar allows microorganisms such as fungi and bacteria to be cultured.
b. Blood Agar: Blood agar is used for the purpose of cultivation and isolation of various strains of pathogenic bacteria.
4. Fastidious Bacteria: A microorganism with a unique nutritional need and will only grow when specific nutrients are included in its feed.
5. Hemolytic: The breakdown of red blood cells and the ability of bacteria colonies to induce hemolysis when it is grown on blood agar. This allows process allows for the process of classifying organisms. 6. Alpha, Beta, Gamma Hemolysis: a. Alpha: A color change occurs where initially it is red and then turns to a very dark green as a result of oxidation of hemoglobin to methemoglobin by hydrogen peroxide. b. Beta: Complete lysis of blood cells. It is presented as a yellowish color on the blood agar medium. This hemolysis happens because of an enzyme produced by a bacterium called streptolysin. c. Gamma: These organisms are known as nonhemolytic and are distinguished based of lack of color change or transparency to the medium under the bacteria colonies. 7. Colony morphology: The morphology (study of the form and structure of living things) of cellular colonies grown in cultures and how different types of bacteria types look growing on agar. Questions 1. Why do we grow bacteria on agar? What is the purpose of this lab test? a. We grow bacteria on agar because it is a controlled environment that is used to culture microorganisms. Because Agar is flexible media with its capability of being in solid/semi solid state, this allow the microbial colonies to grown on the surface by allowing them to grow on a better surface so that the microbial colonies …show more content…
Why do we fire the loop before the streaking process?
a. We fire the loop before the streaking process to ensure that all microbial cells are burned off from the loop so that it does not cause contamination of the culture.
3. How do we get the sample onto the loop?
a. After sterilizing the loop over an open flame, depending if the bacteria is in a liquid or solid form, we dip the loop inside the sample test tube and dip the inoculated loop straight down in the tube. If the sample is a solid the sterilized loop should barely touch the culture.
4. Why do we have to wait for the loop to cool before collecting a sample?
a. We have to wait for the loop to cool before collecting samples because we may kill the bacteria or melt the agar jelly that is going to be in contact with the bacteria.
5. What do you do to the loop in between streak patterns (on the same plate)?
a. After your first streak pattern you should flame the loop again and let it cool. Then you follow the same procedure of lifting the Petri plate, streaking it across the first streak pattern onto the second quadrant of the plate, flame the loop again, etc.
6. How much of the plate do we cover with the primary inoculum?
a. We should cover between a quarter and third of the plate in total