nothing is missing now.you just have to tell what are expected observations.AS WE HAVE TO DO EXPERIMENT AFTER BUT FIRST WRITE THAT WHAT WILL BE EXPECTED FROM THE RESULTS?WE WILL GET PHOTOS WHEN WE PERFORM BUT THEN WE WILL COMPARE WHETHER WHAT WE EXPECTED IS WHAT WE GOT OR IS THE ACTUAL RESULT DIFFERENT.
INTRODUCTION
For acquiring food material, bacteria excrete extracellular enzymes that split larger molecules into smaller units.For example, amylase and cellulase degrade polysaccharides such as starch and cellulose into simple sugars, which are then transported into the cell for metabolic purposes. A variety of proteases degrade protein molecules such as gelatin and casein into amino acids, and lipases split fats into fatty
acids and glycerol. These physiological or biochemical characteristics are used for isolation and identification of bacteria in conjunction with other morphological and cultural methods. In this exercise, you will perform tests related to hydrolytic reactions.
Starch hydrolysisâSince many bacteria are capable of hydrolyzing starch, this test has a fairly wide application. Bacteria that hydrolyze starch produce amylases that yield molecules of maltose, glucose, and dextrins.
Casein hydrolysisâCasein is the predominant protein in milk and its presence causes milk to have its characteristic white color. Many bacteria produce proteases that degrade proteins into peptides and individual amino acids in a process called proteolysis.
MATERIALS
ï·
Nutrient broth cultures of Bacillus subtilis, Escherichia coli andStaphylococcus epidermidis
ï·
Starch agar culture plate
ï·
Casein agar culture plate
ï·
Gramâs iodin
1.Label and streak in a straight line with all the 3 cultures on the starch agar plate ANDon the casein agar plate.
2.Incubate the plates at 37oC for 24-48 hours.
Week 2 âStarch Hydrolysis
1.Add several drops of Gramâs iodine over the growth on the medium. Rotate and tilt the plate gently to spread the iodine. Iodine is a starch indicator and when it comes in contact with a medium of starch, it turns blue.
2.If starch is hydrolyzed and no longer present, the medium will have a clear zone next to the growth.
3. Take a photograph of your plate against a white background. (If you do not have a phone equipped with a camera, ask a lab mate to take a picture for you and have the picture electronically sent to you.)
Week 2 âCasein Hydrolysis
1.Examine the streaks on the casein agar plates. A clear zone adjacent to the growth is evidence of casein (protein) hydrolysis. Discussion Amongst other points, you should address in the discussion whether the observations you made were expected. (You will need to do research to answer address this issue. Make sure you include proper citations?
What is expected observation for it with reference if possible
nothing is missing now.you just have to tell what are expected observations.AS WE HAVE TO DO EXPERIMENT AFTER BUT FIRST WRITE THAT WHAT WILL BE EXPECTED FROM THE RESULTS?WE WILL GET PHOTOS WHEN WE PERFORM BUT THEN WE WILL COMPARE WHETHER WHAT WE EXPECTED IS WHAT WE GOT OR IS THE ACTUAL RESULT DIFFERENT.
INTRODUCTION
For acquiring food material, bacteria excrete extracellular enzymes that split larger molecules into smaller units.For example, amylase and cellulase degrade polysaccharides such as starch and cellulose into simple sugars, which are then transported into the cell for metabolic purposes. A variety of proteases degrade protein molecules such as gelatin and casein into amino acids, and lipases split fats into fatty
acids and glycerol. These physiological or biochemical characteristics are used for isolation and identification of bacteria in conjunction with other morphological and cultural methods. In this exercise, you will perform tests related to hydrolytic reactions.
Starch hydrolysisâSince many bacteria are capable of hydrolyzing starch, this test has a fairly wide application. Bacteria that hydrolyze starch produce amylases that yield molecules of maltose, glucose, and dextrins.
Casein hydrolysisâCasein is the predominant protein in milk and its presence causes milk to have its characteristic white color. Many bacteria produce proteases that degrade proteins into peptides and individual amino acids in a process called proteolysis.
MATERIALS
ï·
Nutrient broth cultures of Bacillus subtilis, Escherichia coli andStaphylococcus epidermidis
ï·
Starch agar culture plate
ï·
Casein agar culture plate
ï·
Gramâs iodin
1.Label and streak in a straight line with all the 3 cultures on the starch agar plate ANDon the casein agar plate.
2.Incubate the plates at 37oC for 24-48 hours.
Week 2 âStarch Hydrolysis
1.Add several drops of Gramâs iodine over the growth on the medium. Rotate and tilt the plate gently to spread the iodine. Iodine is a starch indicator and when it comes in contact with a medium of starch, it turns blue.
2.If starch is hydrolyzed and no longer present, the medium will have a clear zone next to the growth.
3. Take a photograph of your plate against a white background. (If you do not have a phone equipped with a camera, ask a lab mate to take a picture for you and have the picture electronically sent to you.)
Week 2 âCasein Hydrolysis
1.Examine the streaks on the casein agar plates. A clear zone adjacent to the growth is evidence of casein (protein) hydrolysis. Discussion Amongst other points, you should address in the discussion whether the observations you made were expected. (You will need to do research to answer address this issue. Make sure you include proper citations?
What is expected observation for it with reference if possible
