Saturday, December 1, 2007

Concept 27.2

I. A bacterium requires only the amino acid methionine as an organic nutrient and lives in lightless caves. What mode of nutrition does it employ? Explain.

a)Chemoheterotrophic mode of nutrition - a nutritional classification where the microbe gets its energy from chemicals and its electrons and carbon from organic compounds.
b) Chemoheterotrophy; the bacterium must rely on chemical sources of energy, since it is not exposed to light, and it must be a heterotroph if it requires and organic source of carbon rather than CO2.

II. What are the sources of carbon and nitrogen for the cyanobacterium Anabaena?

a) Anabaena is a photoautotroph that obtains its carbon from CO2. As a nitrogen-fixing prokaryote, Anabaena obtains its nitrogen from N2.

No comments: