Q. Intestinal bacteria can grow in the presence of __________ whereas nonintestinal bacteria are usually inhibited. bile saltslow concentration of various dyessugarslow levels of nitrogen Answer: bile salts

Q. Which of the following techniques may be performed quantitatively to determine the number of bacteria of a particular type? Pour plateSpread plateBoth (1) and (2)Streak plate technique Answer: Both (1) and (2)

Q. Cell counting can be carried out by direct microscopic count using petroffhansser counting chamberplate countingmembrane filter countall of the above Answer: all of the above

Q. Important example(s) of enriched medium/media is/ are Loeffler’s serum slopeBordet-gengou mediumBlood agarAll of these Answer: All of these

Q. A disease producing species occurring in a mixed culture can often be selected on the basis of its pathogenic propertiesspecial carbon sourcespecial nitrogen sourcenone of these Answer: pathogenic properties

Q. For the selection of lactobacilli present in cheddar cheese, the pH of the medium is maintained at 6.355.354.355.75 Answer: 5.35

Q. Agar is used for solidifying culture media because it does not affect by the growth of bacteriait does not add to the nutritive properties of the mediumthe melting and solidifying points of agar solution are not the sameall of the above Answer: all of the above

Q. Pseudomonas aeruginosa forms a blue water soluble pigment called pyocyaninchlororaphinpyoverdinß-carotene Answer: pyocyanin

Q. Mac-Conkey medium is an example of transport mediumenrichment mediumdifferential mediumall of these Answer: differential medium

Q. Which of the following bacteria dies quickly after drying? Treponema pallidiumMycobacterium tuberculosisStaphylococcus aureusPseudomonas aeruginosa Answer: Treponema pallidium

Q. The concentration of agar to obtain semi solid media is 1.5-20%0.5% or less>10%>10%but<20% Answer: 0.5% or less

8. For the selection of endospore-forming bacteria, a mixed culture can be heated at 80°C for 10 minutes70°C for 10 minutes60°C for 10 minutes90°C for 10 minutes Answer: 80°C for 10 minutes