Prokaryotic Life Flashcards
What two domains form prokaryotes?
Bacteria and archaea
Where can prokaryotes be found?
prokaryotes thrive everywhere, this includes places too acidic, salty, cold or hot for most other organisms.
What size are bacteria?
Most bacteria are microscopic, which means they are not visible to naked eye, and they very abundant. 10000 prokaryotic species in a handful of soil.
Why do we study microbes?
Because they are amongst the simplest forms of life, it is believed higher life have evolved from microbes, which is why we can use them to know more about evolution. Microbes also make great model systems.
Without microbes all other forms of life would die.
What is mutualism, commensalism and parasitism?
These are symbiotic relationships. Mutualism means when both organisms benefit from each other. Commensalism is when one benefits while the other is not significantly harmed or helped. Parasitism is when one benefits while the other is harmed.
Give example of mutual symbionts?
Aliivibrio fischeri is a bioluminescent bacterium. This means it emits light. It is symbiont of Hawaiian bobtailed squid. When natural light hits the squid at night, the bacteria will live on the dorsal side of body and emit the same amount of light as the natural light. This will hide the silhouette of the squid. The squid on the other hand provides a. Fischeri with shelter and stable nutrient source.
What are obligate aerobes?
Obligate aerobes are organisms that require oxygen for cellular respiration.
What are obligate anaerobes?
Obligate anaerobes are organisms that are poisoned by oxygen. This means they cannot survive in the presence of oxygen.
What are facultative anaerobes?
Facultative anaerobes are organisms that can survive with and without oxygen.
What role do prokaryotes play in chemical recycling?
Chemical recycling is helped by prokaryotes and it plays a major role in it.
What are chemoheterotrophs?
Chemoheterotrophs are a group of bacteria that use organic molecules as their carbon source.
Where can microbes be found?
Microbes are everywhere. In agriculture, food, energy/environment, biotechnology and disease.
What role do chemoheterotrophs play in chemical recycling?
They decompose corpses, dead vegetation and waste products. They help with decaying organic matter, whether plant based or animal based matter. The organic matter is broken from higher carbohydrate down into lower carbohydrate. They also help with nitrogen fixation. This means plants get nitrogen in a form that they can use, nitrogen is unstable. The form is ammonia.
Compare the size of prokaryotes and eukaryotes.
In eukaryotes, the largest cell is caulerpa (green alga), which can grow to 3m, while in prokaryotes the largest bacteria is thiomargarita namibiensis which can grow to 1mm in diameter, most bacteria are smaller than mm and are um.
