1. Figure out some of the prokaryote groups that have members that can cause dis
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Question
1. Figure out some of the prokaryote groups that have members that can cause diseases in humans. Do disease-causing prokaryotes form a monophyletic group? What are the implications of this? List some differences between Bacteria and Archaea. If you had a culture of an unknown prokaryote, could you tell whether it was a bacterium or archaean just by looking? If so, what features would you look for? If not, how could you determine which it was? Let's say you meet a microorganism on the street one day. List three characteristics that would allow you to tell whether it is a prokaryote or a eukaryote You read a paper that says, "The symbiotic alpha-proteobacterium that first took up residence in an early eukaryote would have had a genome that coded for at least 500 proteins and RNAs." No evidence is provided to back up this assertion. Where do you think the estimate of 500 genes came from? 2. 3. 4.Explanation / Answer
1. In prokaryotes, we have two main domains, one is Bacteria and other one is Archaea. Bacteria are diverse in function. They may be pathogenic or non-pathogenic but Archaea are non-pathogenic.
So, bacterial group that are known to cause human diseases lie in the group viz Epsilon proteobacteria like Campylobacter (responsible for causing blood poisoning, intestinal infection), Heliobacter pyroli (responsible for causing human ulcer). Other group having disease causing bacteria include Chlamydias like Chlamydia trachomatis (responsible for causing sexually transmitted disease). Some bacteria of gram-positive like Bacillus anthracis (responsible for causing anthrax, Clostridium botulinum (responsible for causing botulism).
Yes, disease causing prokaryotes form a monophyletic (means all organisms are derived from single ancestor).
Implications of all the disease causing prokaryotes found in one monophyletic group are:
(i) All the prokaryotes whether it is a bacteria or Archaea are derived from one ancestor.
(ii) During the course of evolution, some prokaryotes divided in to bacteria and some to archaea.
(iii) Bacteria are diverse in function. They may be pathogenic or non-pathogenic but Archaea are non-pathogenic.
2. Differences between Archaea and bacteria are:
(i) Bacteria are diverse in function. They may be pathogenic or non-pathogenic but Archaea are non-pathogenic.
(ii) Second difference is the cell wall composition. Bacteria cell wall contain peptidoglycans s. and archaea do not contain peptidoglycan in their cell walls.
(iii) Another difference lies in the cell division that is different in both.
(iv) Bacteria is able to form spores that are able to survive for long time but this ability is not found in archaea.
No, by looking the culture, we cannot identify that whether it is a bacteria or Archea. by looking the cell wall we can be sure about that.
3. Three characterstics that tell whether microorganism is a prokaryotes or eukaryotes are:
(i) Prokaryotes do not have cell bound organelles.
(ii) Prokaryotes do not have mitochondria.
(iii) Prokaryotes do not have lysosomes.
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