Question

5. You received a water from a local lake to determine the bacterial cells count, you did the count using both direct microscopic count and the plate count methods. Which methods would likely give a higher bacterial count? And Why? -- 6- Fermentation end products help in identification of bacteria. If you agree with the above statement, give a short explanation of why you agree and include an example. If you do not agree give a short explanation why you disagree? - 7- Place an X under the pathway the following types of orsanism can utilize to obtain energy- Glycolysis fermentation Krebs's cycle ETC Obligate aerobic Obligate anaerobic Go to the Next page:-

Answer 1

5. Agar plate count

The direct microscopic count of individual cells per cubic centimeter varied from 4.8 to 6.2 times greater than the count of the groups of bacteria under the microscope, and from 3 to 4.5 times greater than the agar plate colony count. The plate count on either plain or lactose agar was greater than the corresponding microscopic group counts. This relationship is to be expected in most samples due to the breaking up of the groups into smaller components during the process of plating the milk.

The individual cell count averaged 4.5 times greater than the plain agar plate count but where lactose was added this difference was reduced to 3 times. There was likewise a reduction in the variability as well as a noticeable increase in the correlation. Undoubtedly the addition of lactose to the medium would materially increase the accuracy of the plating method.

6.Yes,fermentation end products help in identification of bacteria.

For example, enteric bacteria are known for their ability to perform mixed acid fermentation, reducing the pH, which can be detected using a pH indicator.

7.

Obligate Obligate X Glycodiysis X X fermentation Kolbe FTC ..... X. X. . ..... anaerobie