Question

Explain the domains of life

Answer 1

Organisms can be classified into one of three domains based on differences in the sequences of nucleotides in the cell's ribosomal RNAs (rRNA), the cell's membrane lipid structure, and its sensitivity to antibiotics. The three domains are the Archaea, the Bacteria, and the Eukarya

Answer 2

Answer :

Domains of Life

• Domains of life are also called three domain system.
• It introduced by Carl Woese in 1990.
• It includes three domains and six kingdoms.
• All the three domains have same common ancestor called are Progenote.
• This classification is done on the basis of 16 s ribosomal RNA genes.
• The three domains are :

1. Bacteria
2. Archaea
3. Eukarya

Bacteria -

• Bacteria includes Kingdom Eubacteria.
• They have circular DNA chromosome.
• They are prokaryotic cells.
• They have peptidoglycan cell wall.
• They have straight chain phospholipids.
• They are antibiotic sensitive.
• The plasma membrane is made up of bilayer of lipids.

Archaea -

• Archaea includes Kingdom Archaebacteria.
• They have circular DNA chromosome.
• They have prokaryotic cell type.
• There presence of peptidoglycan in cell walls.
• They have the presence of branched chain phospholipids.
• They are antibiotic insensitive.
• The cell wall is made up of polysaccharides and proteins.
• The plasma membrane is made up of branched chain lipids and N-phytanyl side chains which decreases membrane fluidity.

Eukarya -

• Eukarya four kingdoms namely : Protista, Fungi, Plantae and Animalia.
• They have linear DNA chromosome.
• They have eukaryotic cell time.
• If the cell walls are present, they are variable.
• They have the presence of straight chain phospholipids.
• They are antibiotic insensitive.