(A) Pyruvic acid (CH3COCOOH + 2H) ------> lactic acid (CH3CHOHCOOH)
(B) Pyruvic acid (CH3COCOOH + 2H) ------> ethyl alcohol (CH3CH2OH + CO2)
(C) Pyruvic acid (CH3COCOOH + 2H) ------> acetic acid (CH3COOH + CO2 )
Test tube rack
*2.5% NaCl (salt) solution
Balloon 7 inch round (to fit over test tube)
* To prepare 100 ml of a 2.5% salt solution, dissolve 2.5 grams of NaCl in 97.5 ml of water.
**This is a stain for tissue slides. You can use the blue or green tropical fish medicine as a substitute. Sometimes I even prefer it.
1. Pack the test tube with shredded cabbage.
2. Cover with 2.5% NaCl (salt) solution until the test tube is full.
3. Cover the test tube with the balloon.Try to leave as little air as possible in the balloon. For the next 2 weeks, make sure the test tube remains full. Replenish with more NaCl solution as needed.
4. Check the condition of the cabbage cells. Make a wet mount of a few cells peeled from the lower epidermis. Stain these cells using methylene blue. Examine under the microscope using middle and high power. Look carefully to see if the cell membrane has separated from the cell wall. Record in the DATA TABLE.
5. To check for the presence of bacteria, make a wet mount by gently scraping the bottom of the cabbage with a toothpick and putting it on a slide with a drop of brine. Stain with methylene blue and examine under high power. Record in the DATA TABLE.
6. Make daily observations and recordings for the next 10 days. Remember to replenish with more NaCL solution as needed. Record all data in the DATA TABLE.
7. On day 10, in addition to the other data, check the condition of the cabbage cells and the presence of bacteria as you did in steps 4 and 5. Record your observations and make a sketch of any bacteria you see.
8. Make a graph showing the pH from day 0 to day 10.
YourDATA TABLE should contain the following for days 1-10: date, color of cabbage, texture of cabbage, odor, any gasses produced, and pH. Also for days 1 and 10, condition of cabbage cells, presence of bacteria in brine, and description of bacteria in brine.