MOLECULES TO CELLS - ARCHAEA

What type of cells are Archaea?

Prokaryotic cells that do not contain a nucleus or cell organelles.

What is the shape and size diversity of Archaea?

Archaea range in shape and size, including cocci with flagella, square, short bacillus, lobed cocci, and filamentous forms.

How do archaeal cell walls differ from bacterial cell walls?

Archaeal cell walls do not contain peptidoglycan; they are composed of polysaccharides, proteins, and glycoproteins, and some archaea lack a cell wall entirely.

What is pseudomurein?

A major component of the cell wall in some archaea, similar in structure to peptidoglycan.

What is the S-layer in Archaea?

The most common cell wall structure in archaea, composed of protein and glycoprotein, providing shape and protection.

What distinguishes archaeal cell membranes from those of bacteria and eukarya?

Archaeal membranes consist of ether linkages and lipid tails made of isoprenoid chains, allowing for greater stability and the formation of bilayers or monolayers.

What are Hami in Archaea?

Pili-like structures used for attachment and biofilm formation.

How do Archaea reproduce?

They divide by binary fission, producing two genetically identical daughter cells.

What types of metabolism do Archaea exhibit?

They can be aerobic, anaerobic, or phototrophic, with some species like Halobacterium salinarum utilizing light-driven ATP synthesis.

What are halophiles?

Archaea that require 9-32% NaCl, found in salt lakes and salted foods, maintaining osmotic balance through K+ accumulation.

What are thermophiles and hyperthermophiles?

Archaea that thrive in high-temperature environments, often above 100°C, found in geothermal habitats.

Are all Archaea extremophiles?

No, only a portion are extremophiles; 20% of prokaryotes are found in oceans, and 1% in soil, with some playing roles in nitrogen fixation.

What ecological roles do some Archaea play?

They are important in biogeochemical cycles, including the production of natural fertilizers and capturing nitrogen.

What is the significance of the inability to culture many Archaea in the lab?

Many Archaea are slow-growing and require extreme conditions, making them difficult to study outside their natural habitats.

What is the role of glycoprotein cell walls in halophiles?

They stabilize the cell walls in high-salinity environments.

What is the function of archaeal flagella?

Smaller than bacterial flagella, they rotate using ATP to drive motility.

What is the significance of the unique lipid composition in archaeal membranes?

It provides extra resistance to extreme heat and harsh environments.

What is the primary method of energy production in Halobacterium salinarum?

It uses bacteriorhodopsin for light-driven ATP synthesis.

What is the impact of the geological environment on Archaea?

They are often found in extreme environments, influencing their growth and metabolic processes.