Chapter 20, Problem 1CHI

Some believe that archaea should not be separate from bacteria because both groups are prokaryotic. Do you agree or disagree? Explain your reasoning.

Summary Introduction

Archaea and bacteria are referred to as prokaryotic unicellular organisms. Initially, archaea were classified as bacteria, thereby receiving the name archaebacteria. Since 1960s, genetic, biochemical, and genomic analyses are combined with developed methods for archaeal and bacterial cell imaging. As a result, it was concluded that Archaea and Bacteria are belongs to different taxa.

Explanation of Solution

Archaea and bacteria are referred to as prokaryotic organisms. Based on morphological features, they seem to be the same taxonomic group. However, based on genomic analysis, it was revealed that both organisms belong to different domains. In 1977, the American biophysicist and microbiologist revealed the third domain of life, which is known as archaea. This is achieved by the analysis of phylogenetic taxonomy of 16S ribosomal ribonucleic acid (rRNA).

The other features that reveals that they are belonged to different domain are as follows:

The plasma membrane of archaea is made up of strikingly different lipids compared to those present in the plasma membrane of bacteria. The bacterial plasma membrane is comprised of ester-linked phospholipids like hapanoids and sterols, whereas the archaeal plasma membrane is comprised of diether glycerol or tetraether glycerol. Secondly, the cell wall of archaea is diverse compared to bacterial cell wall. This is because; the cell wall of archaea lacks peptidoglycan whereas the bacterial cell wall is made up of peptidoglycan.

Therefore, the above explained differences made this statement to disagree. Hence, archaea should be separated from the bacteria.