Gram staining lab report
Gram Staining Lab
Introduction
Gram staining is a very important technique used in biology labs all over the world. It is a technique used to differentiate types of bacteria using certain physical and chemical characteristics of their cell walls. Gram positive bacteria (which show up purple after the gram staining process) have a very thick layer of peptidoglycan where gram negative bacteria (which show up pink after the gram staining process) have a much thinner layer of peptidoglycan. One thing to note is that not all bacteria are gram positive or gram negative, some are non-reactive to this type of staining. Bacteria that are non-responsive to this technique are known as gram insensitive.
I hypothesize that in the cultures used in this lab for gram staining will contain many gram negative and gram positive bacteria.
Material and Methods
The following things are needed to run a gram staining experiment:
1. Bacterial cultures
2. Glass slides
3. Cover slips
4. Ammonium Oxalate-Crystal Violet stain
5. Gram’s Iodine Solution
6. Ethyl Alcohol
7. Safranin Solution
8. Paper towels
9. Water
10. Bunsen Burner (Lighter will suffice)
11. Microscope 1. Prepare and heat-fix smears. 2. Stain the slides as follows: a. Flood the crystal violet for one minute. b. Pour off excess dye and wash gently in tap water and drain the slide against a paper towel. c. Expose the smears to Gram's iodine for one minute by washing with iodine, then adding more iodine and leaving it on the smear until the minute is over. d. Wash with tap water and drain carefully. (Do not blot.) e. Wash with 95% alcohol for 30 seconds. f. Wash with tap water at the end of the 30 seconds to stop the decolorization. Drain. g. Counterstain with 0.25% safranin for 30 seconds. h. Wash, drain, blot, and examine under oil. i. Draw the cells showing morphology, grouping, and relative sizes. Color a few of the cells of each
Introduction
Gram staining is a very important technique used in biology labs all over the world. It is a technique used to differentiate types of bacteria using certain physical and chemical characteristics of their cell walls. Gram positive bacteria (which show up purple after the gram staining process) have a very thick layer of peptidoglycan where gram negative bacteria (which show up pink after the gram staining process) have a much thinner layer of peptidoglycan. One thing to note is that not all bacteria are gram positive or gram negative, some are non-reactive to this type of staining. Bacteria that are non-responsive to this technique are known as gram insensitive.
I hypothesize that in the cultures used in this lab for gram staining will contain many gram negative and gram positive bacteria.
Material and Methods
The following things are needed to run a gram staining experiment:
1. Bacterial cultures
2. Glass slides
3. Cover slips
4. Ammonium Oxalate-Crystal Violet stain
5. Gram’s Iodine Solution
6. Ethyl Alcohol
7. Safranin Solution
8. Paper towels
9. Water
10. Bunsen Burner (Lighter will suffice)
11. Microscope 1. Prepare and heat-fix smears. 2. Stain the slides as follows: a. Flood the crystal violet for one minute. b. Pour off excess dye and wash gently in tap water and drain the slide against a paper towel. c. Expose the smears to Gram's iodine for one minute by washing with iodine, then adding more iodine and leaving it on the smear until the minute is over. d. Wash with tap water and drain carefully. (Do not blot.) e. Wash with 95% alcohol for 30 seconds. f. Wash with tap water at the end of the 30 seconds to stop the decolorization. Drain. g. Counterstain with 0.25% safranin for 30 seconds. h. Wash, drain, blot, and examine under oil. i. Draw the cells showing morphology, grouping, and relative sizes. Color a few of the cells of each