In: Biology
is it possible to have the following results? explain
why or why not?
A: tsia-yellow slant and red butt?
B: tsia-yellow butt and blackening in the media?
C:litmus milk- clearing of fluid and breaks in the clot?
D: Litmus milk- blue color with an acid curd?
E:SIM- Motility and no black precipitate?
Ans. A In tsia yellow slant and red butt wont be observed. As it neither indicates the presence of gas nor the presence of H2S also non of the acid-acid, acid-alkali, alkali-alkali reaction coincides with the observation.
Ans B. Yellow butt and blackening of the media can be observed due to production of H2S gas and the black colouration would be due to the feroous sulfide formation.
Ans C. In litmus milk the reversal of the given procedure would occur. AS a result of which there would not be clearing of fluid and breaking into clot. On the contrary there would be digestion of casein and formation of clot.
Ans D. Litmus milk blue color with an acid curd. It cannot take place as the blue coluration would occur only in case of alkaline medium and not in acid medium. The acid curd is characterised by pink colouration due to lactose fermentation.
Ans E. It is possible due to reduction of H2S to ferrous sulphide. Hence the SIM motility and black precipitate can occur.