Prokaryotic metabolism

Question 1

What are the 4 types of category that a Prokaryote can acquire energy & carbon?

Answer 1

• Photoautotrophs
• Chemolithoautotrophs
• Photoheterotrophs
• Chemoheterotrophs

Question 2

What is the difference between an Autotroph & a Heterotroph?

Answer 2

• Autotrophs obtain their carbon from the inorganic CO2

- Heterotrophs obtain at least some of their carbon from organic molecules (glucose)

Question 3

What is Photoautotroph?

Answer 3

-Many bacteria carrying out photosynthesis using energy from sunlight to build organic molecules from CO2

Question 4

How does Cyanobacteria Photoautotroph?

Answer 4

• 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

Question 5

What can other bacteria use for Photoautotroph?

Answer 5

• 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)

Question 6

How does Archeal Species Photoautotroph?

Answer 6

• 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

Question 7

What is Chemolithoautotrophs?

Answer 7

-Some prokaryotes obtain energy by oxidizing inorganic substances

Question 8

How do Nitrifiers Chemolithoautotroph?

Answer 8

-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)

Question 9

What are Photoheterotrophs?

Answer 9

-Purple & Green non-sulfur bacteria use light as their source of energy but obtain carbon from organic molecules (alcohols & carbs produced by others)

Question 10

What are Chemoheterotrophs?

Answer 10

• The majority of prokaryotes obtain both carbon atoms & energy from organic molecules
• Include decomposers, most pathogens, human beings, & nonphotosynthetic eukaryotes

Question 11

What do proteins from gram-negative bacteria have to allow it to attack other cells?

Answer 11

-They must have special signal sequences that allow them to pass through the bacterium’s double membrane

Question 12

What is the Type III system?

Answer 12

-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

Question 13

What genes seem more closely related than bacteria themselves?

Answer 13

• 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

Question 14

What are the many diseases of plants associated with?

Answer 14

• A particular Heterotrophic bacteria

- Most bacteria that causes plant diseases are members of the group of rod-shaped gram-negative Pseudomonads

Question 15

What is a well known example of bacterial disease?

Answer 15

-Fire Blight= destroys apple & pear trees & related plants

Question 16

How are Plant diseases manifested?

Answer 16

-As spots of various sizes on stems, leaves, flowers, or fruits