@@sacapuntasfregerio4274 1. What are the two harmful bacteria we are investigating? Salmonella E. coli 2. Why are the air bubbles seen as a sign of contamination? Bacteria produce gas when they grow. 3. Who developed Gram staining? Hans Christian Gram. did What do we use it for? used for classifying and identifying types of bacteria based on how much peptidoglycan is in the cell membranes. 4. Are the bacteria that would indicate contamination Gram-negative or positive? they would be pink which means they are gram negative Which color are they? pink 5. Why do some bacteria stain pink and others stain purple when they are put through the same staining process (be specific about the difference between the two types of bacteria that causes the difference in color)? The crystal violet (purple colored stain) sticks to the peptidoglycan in cells that have a high amount of peptidoglycan in their cell membrane gram-positive (purple) if there is a small amount of peptidoglycan then the crystal violet (purple colored stain) will not be able to stick to the bacteria so it can be removed and not leave any purple on the bacteria. Next pink stain (called safranin) will be used, and the pink stain can stain cells with low amount of peptidoglycan to identify them as gram-negative (pink) cells 6. What could happen if you overheat the slide during the preparation? The protein in the bacteria can get denatured which can lead to inaccurate staining 7. What could happen if you don’t dry the slide completely during the preparation? The bacteria could get washed off. 8. Detail the Gram staining process with applicable times for each step. Once you have dryed the bacteria on your slide obtain 4 chemicals 1. crystal violet 2. grams iodine 3. 95% alchol 4. safranin. First apply crystal violet to the bacteria on the slide. This will stain the bacteria purple if there a lot of peptidoglycan in the cell membrane. Because + ions in the dye are polarly attracted to the negatively charged components in the cell membrane. Let the crystal violet sit on the bacteria for 60 minutes. Then rinse the slide under slow moving water. Next apply grams iodine to the bacteria completely cover it with the iodine for 60 seconds this will ensure the stain from the crystal violet will stay in the bacteria. After the 60 seconds rinse the iodine off with slow running water. Next apply the 95% alcohol to the bacteria completely cover it in for 30 seconds then rinse it off. This alcohol is used to remove any loose stain that is not stuck in the bacteria. So it should remove all the purple from the gram-negative bacteria but leave all of the gram-positive bacteria purple. Now its is time for the last step. In this step you stain the gram-negative bacteria pink using the safranin. Completely cover the bacteria with the safranin for 60 seconds then rinse it off with slow running water and dry between 2 sheets of bibulous paper. 9. Is the yogurt contaminated? if yes What should our next steps be? Next step is to Determine how it got contaminated and identify the exact type of gram-negative bacteria is in the yogurt.
I have learned more from this demonstration then, I did in my lab class. Thanks!
Who else is a student?
who else is a moron
@@sacapuntasfregerio4274 1. What are the two harmful bacteria we are investigating? Salmonella E. coli
2. Why are the air bubbles seen as a sign of contamination? Bacteria produce gas when they grow.
3. Who developed Gram staining? Hans Christian Gram. did What do we use it for? used for classifying and identifying types of bacteria based on how much peptidoglycan is in the cell membranes.
4. Are the bacteria that would indicate contamination Gram-negative or positive? they would be pink which means they are gram negative
Which color are they? pink
5. Why do some bacteria stain pink and others stain purple when they are put through the same staining process (be specific about the difference between the two types of bacteria that causes the difference in color)? The crystal violet (purple colored stain) sticks to the peptidoglycan in cells that have a high amount of peptidoglycan in their cell membrane gram-positive (purple) if there is a small amount of peptidoglycan then the crystal violet (purple colored stain) will not be able to stick to the bacteria so it can be removed and not leave any purple on the bacteria. Next pink stain (called safranin) will be used, and the pink stain can stain cells with low amount of peptidoglycan to identify them as gram-negative (pink) cells
6. What could happen if you overheat the slide during the preparation? The protein in the bacteria can get denatured which can lead to inaccurate staining
7. What could happen if you don’t dry the slide completely during the preparation? The bacteria could get washed off.
8. Detail the Gram staining process with applicable times for each step. Once you have dryed the bacteria on your slide obtain 4 chemicals 1. crystal violet 2. grams iodine 3. 95% alchol 4. safranin. First apply crystal violet to the bacteria on the slide. This will stain the bacteria purple if there a lot of peptidoglycan in the cell membrane. Because + ions in the dye are polarly attracted to the negatively charged components in the cell membrane. Let the crystal violet sit on the bacteria for 60 minutes. Then rinse the slide under slow moving water. Next apply grams iodine to the bacteria completely cover it with the iodine for 60 seconds this will ensure the stain from the crystal violet will stay in the bacteria. After the 60 seconds rinse the iodine off with slow running water. Next apply the 95% alcohol to the bacteria completely cover it in for 30 seconds then rinse it off. This alcohol is used to remove any loose stain that is not stuck in the bacteria. So it should remove all the purple from the gram-negative bacteria but leave all of the gram-positive bacteria purple. Now its is time for the last step. In this step you stain the gram-negative bacteria pink using the safranin. Completely cover the bacteria with the safranin for 60 seconds then rinse it off with slow running water and dry between 2 sheets of bibulous paper.
9. Is the yogurt contaminated? if yes What should our next steps be? Next step is to Determine how it got contaminated and identify the exact type of gram-negative bacteria is in the yogurt.
i hate biomed