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A student was culturing E. coli (a bacterium) in a Petri-dish. He placed the Petri-dish in an incubator at 30oC.He removed it from the incubator...

      

A student was culturing E. coli (a bacterium) in a Petri-dish. He placed the Petri-dish in an incubator at 30oC.He removed it from the incubator the following day and found that five colonies of bacteria had grown. He decided to return it into the incubator to give it more time. When he removed it fourteen days later, he could not observe any colony.

a) Why was there no colony on the fourteenth day?

b) Explain how bacteria cause spoilage of stored food in warm moist conditions.

c) Name other organisms which also cause food spoilage.

d) State their economic importance to nature.

  

Answers


Martin
(a) The bacteria ad exhausted the available food materials and they died;

(b) They multiply very fast as they feed on the substances; release toxic waste on food then die
there causing food spoilage

(c) fungi;

(d)
– Speed up recycling of matter in the ecosystem;
- Breaks down /decompose dead complex organic matter
marto answered the question on October 4, 2019 at 08:35


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