Question

2. What is the enzyme being tested? 3. What is the substrate if the enzyme? 4. For what purpose do bacteria that have the enzyme utilize it?

Answer 1

ANSWERS

2. What is the ezyme being tested?

answer: Hydrolytic exoenzymes such as Lipase and Casease

3.What is the substrate if the enzyme?

answer:

TEST	ENZYME	SUBSTRATE
Lipase Test	Lipase	TRIBUTYRIN
Casease Test	Casease	CASEIN

4.For what purpose do bacteria that have the enzyme utilize it ?

answer:

In case of Lipase Test

Lipids are fatty acids used by some bacterium to produce energy in the form of ATP and metabolites used to drive anabolic pathways,citric acid cycle, Krebs cycle and glycolysis.The lipids must first be hydrolyzed by an exoenzyme synthesized within and secreted from bacteria called lipase.Hydrolytic exoenzymes digest large lipid macromolecules outside the bacterial cell so that their smaller subunits can be transported inside the cell.

In case of Casease Test

Some bacteria posses a hydrolytic enzyme called casease that can be secreted and used to digest casein so that thebacterium can utilize the amino acid subunits that are liberated during hydrolysis to build it's own proteins.These proteins arevrequired for survival and metabolism.When a large protein like casein is chopped into smaller amino acid subunits by enzymatic activity,theseamino acids can then more readily cross the bacterial cell wall for internalization.

6.What will occur if the plate is incubated right side up?

answer:  condensation  drip onto the plate and interfere with the developing microbes.it more difficult for contaminants to enter the growing medium.

7.What will occur if the plate is incubated for more than 24-48 hours?

answer :This encourages growth of the culture without growing human pathogens which thrive at body temperature (37°C). For safety reasons, plates and equipment should be sterilised after use.It is better to have a culture with minimum of dead cells, so early stationery phase is the best. So incubating longer would have many dead cells will contaminate your culture plate.