archaea

microbiology exam 2

What major cell type is archaea a part of?

prokaryotes, like bacteria

How are archaea morphologically diverse? What makes them able to be morphologically diverse?

Although most achaea are coccus or bacillus, they can come in a wide range of shapes, even more than bacteria

This is partly because they lack the rigid peptidoglycan wall characteristic of bacteria

What kind of environments do bacteria grow optimally in? What name would describe this?

• many grow optimally in extreme environmental conditions

• extremophiles

What would be the name for an organism that likes to grow in very high temperatures?

hyperthermophiles

What would be the name for an organism that likes to grow in very high salt?

extreme halophiles

What would be the name for an organism that likes to grow in very high acidic conditions?

acidophiles

What would be the name for an organism that likes to grow in very high anaerobic environments?

especially methanogens

What archaeal species is currently established as a human pathogen?

None

How do archaea MAINLY differ from bacteria?

the plasma membrane and the cell wall (archaea lack peptidoglycan)

Describe archaeal cell walls.

They can vary in many ways, but they always lack peptidoglycan

Describe the plasma membrane of archaea

Archaeal lipids can be diether lipids or tetraether lipids (having two hydrophilic heads)

What do tetraether lipids do in archaea cells?

They span the entire membrane and form a lipid monolayer

What is the purpose of a monolayer?

More rigid and stable than a typical bilayer. It is less likely to come apart or become excessively fluid at high temperatures. Usually present in archaea in high temperatures

What function does a lipid monolayer serve?

serves same basic barrier function as the lipid bilayer found in bacteria and eukaryotes.