Prokaryotic metabolism Flashcards
What are the 4 types of category that a Prokaryote can acquire energy & carbon?
- Photoautotrophs
- Chemolithoautotrophs
- Photoheterotrophs
- Chemoheterotrophs
What is the difference between an Autotroph & a Heterotroph?
- Autotrophs obtain their carbon from the inorganic CO2
- Heterotrophs obtain at least some of their carbon from organic molecules (glucose)
What is Photoautotroph?
-Many bacteria carrying out photosynthesis using energy from sunlight to build organic molecules from CO2
How does Cyanobacteria Photoautotroph?
- They use Chlorophyll-a as the key light-capturing pigment and H2O as an electron donor= releases oxygen gas as a by-product
- Makes Cyanobacteria oxygenic
- Also same process for Archeal species
What can other bacteria use for Photoautotroph?
- They can use Bacteriochlorophyll as their light-capturing pigment & H2S as an electron donor= leaves elemental sulfur as the by-product
- They DO NOT produce oxygen (anoxygenic)
How does Archeal Species Photoautotroph?
- Same simple mechanisms for Cyanobacteria
- But involves a single protein= Bacteriorhodopsin= uses energy from light to translocate proteins across the membrane= provides proton motive for ATP synthesis
What is Chemolithoautotrophs?
-Some prokaryotes obtain energy by oxidizing inorganic substances
How do Nitrifiers Chemolithoautotroph?
-They oxidize ammonia or nitrate to obtain energy= produces nitrate that is taken up by plants= Nitrification (plants absorb nitrogen in the form of nitrate)
What are Photoheterotrophs?
-Purple & Green non-sulfur bacteria use light as their source of energy but obtain carbon from organic molecules (alcohols & carbs produced by others)
What are Chemoheterotrophs?
- The majority of prokaryotes obtain both carbon atoms & energy from organic molecules
- Include decomposers, most pathogens, human beings, & nonphotosynthetic eukaryotes
What do proteins from gram-negative bacteria have to allow it to attack other cells?
-They must have special signal sequences that allow them to pass through the bacterium’s double membrane
What is the Type III system?
-Is a system that acts like a kind of molecular syringe that allows the pathogen to inject directly into the cytoplasm of the host cells
What genes seem more closely related than bacteria themselves?
- The genes that encode for the Type III system
- These genes are turning up in other gram-negative animal pathogens & plant pathogens
- These genes are also closely related to those that code for bacterial flagella
What are the many diseases of plants associated with?
- A particular Heterotrophic bacteria
- Most bacteria that causes plant diseases are members of the group of rod-shaped gram-negative Pseudomonads
What is a well known example of bacterial disease?
-Fire Blight= destroys apple & pear trees & related plants