Question

1. In terms of microbial diversity, what would you expect to find when examining a sample of ice water obtained from the North Pole? A) High species richness and high species abundance B) High species richness and low species abundance c) Low species richness and low species abundance D) Low species richness and high species abundance 2. Which of the following factors does NOT influence the types of microbial activities in an ecosystem? A) The noise levels in an ecosystem B) Species composition C) Population sizes D) The physiological state of the microorganisms in each habitat 3. At what percentage of the maximal laboratory growth rate do typical soil bacteria grow? A) Less than 1% B) Approximately 50% C) Approximately 25% D) At least 75% Which of the following statements about bacterial biofilms is NOT correct? A) Biofilms are functional microbial communities and not just cells trapped in a sticky matrix. B) Biofilms may contain one or two species or, more commonly, several species of bacteria. C) The cells within a biofilm maintain an independent existence. D) Biofilms typically contain several porous layers.

Answer 1

1.C) Low species richness and low species abundance

Since it is an extreme cold zone with very limited resources and harsh envirnomental conditions, we will find low species richness and low species abundance.

2. A) Noise levels in an ecosystem

Noise levels are not known to affect the microbial activities in an ecosystem. Population sizes determine the activities since large population may imply dominance of one bacteria over another and vice versa. Species composition affects activities since it determines the level of competition for resources. Physiological state of microorganisms in each habitat directly affects their metabolism and survival.

4. C) The cells within a biofilm maintain an independent existence.

The cells within a biofilm are not independent . Rather they communicate with each other through cell - to- cell signalling for overall population growth and convey message to each other.

Biofilms are infact communities of two or several species of bacteria which grow in several porous layers. Some communities may be restricted to lower layers whereas other may grow in above layers. Few bacteria can grow in all layers too.