Question

Bacteria and Archaea

What Are the Bacteria and Archaea?
Bacteria and Archaea may look similar at first glance, but are very different? How so?

Create a timeline for the important roles bacteria played in the evolution of Earth as we know it.

Why are Bacteria and Archaea considered the most ancient, diverse, abundant, ubiquitous organisms on the planet?

Why Do Scientists Study Bacteria and Archaea?

What Themes Occur in the Diversification of Bacteria and Archaea? What do all bacteria and archaea have in common?

How are different types of bacteria different from one another? How Do Biologists Study Bacteria and Archaea?

Extremophiles: how do some bacteria thrive in extreme conditions? How Do Small Cells Affect Global Change?

Metabolic Diversity: Where Do Bacteria and Archaea Get the Energy to Make ATP, and Where Do They Get Carbon to Build Macromolecules?

Answer 1

Bacteria:

Bacteria are microscopic, single-celled organisms that thrive in diverse environments. These organisms can live in soil, the ocean and inside the human gut.Bacteria (singular: bacterium) are classified as prokaryotes, which are single-celled organisms with a simple internal structure that lacks a nucleus, and contains DNA that either floats freely in a twisted, thread-like mass called the nucleoid, or in separate, circular pieces called plasmids.

Archae:

Archaea is any of a group of single-celled prokaryotic organisms (that is, organisms whose cells lack a defined nucleus) that have distinct molecular characteristics separating them from bacteria (the other, more prominent group of prokaryotes) as well as from eukaryotes (organisms, including plants and animals, whose cells contain a defined nucleus).

Difference Between Archaea and Bacteria:

1. Likewise the bacteria, archaea are single-cell, simple prokaryotes, lacking the well-defined nucleus and other organelles. Archaea are capable of surviving under the extreme condition and so are considered as extremophiles.
2. Archaea are found in the unusual environment like in hot spring, ocean depth, salt brines, while bacteria are found everywhere like in the soil, water, living and non-living organisms.
3. The cell wall of archaea is pseudopeptidoglycan, as they have ether bonds with the branching of aliphatic acids, whereas bacteria have lipid membrane ester bonds with fatty acids.
4. Archaea exactly do not follow glycolysis or Kreb cycle but uses similar pathway, but bacteria follows these pathways to produce energy.
5. Methanogens, Halophiles, Thermoacidophiles are the type of archaea, while gram positive and gram negative are the types of bacteria.
6. Archaea reproduce asexually by binary fission, fragmentation, or by the budding process, on the other hand, bacteria can produce spores which allow them to live in unfavourable condition and they divide sexually as well as asexually.
7. In archaea features like thymine is absent in the tRNA (transferase RNA) and introns are present, whereas in bacteria thymine is present in the tRNA and introns are absent.
8. In archaea, the RNA polymerase is complex and contains ten subunits, while in RNA polymerase in bacteria is simple and contains four subunits.
9. Pyrolobus fumarii, Sulfolobus acidocaldarius, Pyrococcus furiosus, Methanobacterium formicum are few examples of archaea. Streptococcus pneumoniae, Yersinia pestis, Escherichia coli (E.coli), Salmonella enterica, are the examples of bacteria.

Why Bacteria and Archaea considered the most ancient, diverse, abundant, ubiquitous organisms on the planet?

Ans:-

Prokaryotes, which include both bacteria and archaea, are found almost everywhere – in every ecosystem, on every surface of our homes, and inside of our bodies! Some live in environments too extreme for other organisms, such as hot vents on the ocean floor.Although they are found all around us, prokaryotes can be hard to detect, count, and classify. The prokaryotic species we know of today are a tiny fraction of all prokaryotic species thought to exist.hese organisms are abundant and ubiquitous; that is, they are present everywhere. In addition to inhabiting moderate environments, they are found in extreme conditions: from boiling springs to permanently frozen environments in Antarctica; from salty environments like the Dead Sea to environments under tremendous pressure, such as the depths of the ocean; and from areas without oxygen, such as a waste management plant, to radioactively contaminated regions, such as Chernobyl. Prokaryotes reside in the human digestive system and on the skin, are responsible for certain illnesses, and serve an important role in the preparation of many foods.

How are different types of bacteria different from one another?

Ans:-

There are many different types of bacteria. One way of classifying them is by shape. There are three basic shapes.

• Spherical: Bacteria shaped like a ball are called cocci, and a single bacterium is a coccus. Examples include the streptococcus group, responsible for “strep throat.”
• Rod-shaped: These are known as bacilli (singular bacillus). Some rod-shaped bacteria are curved. These are known as vibrio. Examples of rod-shaped bacteria include Bacillus anthracis (B. anthracis), or anthrax.
• Spiral: These are known as spirilla (singular spirillus). If their coil is very tight they are known as spirochetes. Leptospirosis, Lyme disease, and syphilis are caused by bacteria of this shape.

Extremophiles: how do some bacteria thrive in extreme conditions?

Ans:-

Extremophile, an organism that is tolerant to environmental extremes and that has evolved to grow optimally under one or more of these extreme conditions, hence the suffix phile, meaning “one who loves.”

Extremophiles are of biotechnological interest, as they produce extremozymes, defined as enzymes that are functional under extreme conditions. Extremozymes are useful in industrial production procedures and research applications because of their ability to remain active under the severe conditions (e.g., high temperature, pressure, and pH) typically employed in these processes.

Extremophiles may be described as acidophilic (optimal growth between pH 1 and pH 5); alkaliphilic (optimal growth above pH 9); halophilic (optimal growth in environments with high concentrations of salt); thermophilic (optimal growth between 60 and 80 °C [140 and 176 °F]); hyperthermophilic (optimal growth above 80 °C [176 °F]); psychrophilic (optimal growth at 15 °C [60 °F] or lower, with a maximum tolerant temperature of 20 °C [68 °F] and minimal growth at or below 0 °C [32 °F]); piezophilic, or barophilic (optimal growth at high hydrostatic pressure); oligotrophic (growth in nutritionally limited environments); endolithic (growth within rock or within pores of mineral grains); and xerophilic (growth in dry conditions, with low water availability). Some extremophiles are adapted simultaneously to multiple stresses (polyextremophile); common examples include thermoacidophiles and haloalkaliphiles.

Where Do Bacteria and Archaea Get the Energy to Make ATP, and Where Do They Get Carbon to Build Macromolecules?

Ans:-

Prokaryotes can use different sources of energy to assemble macromolecules from smaller molecules. Phototrophs (or phototrophic organisms) obtain their energy from sunlight. Chemotrophs (or chemosynthetic organisms) obtain their energy from chemical compounds. Chemotrophs that can use organic compounds as energy sources are called chemoorganotrophs. Those that can also use inorganic compounds as energy sources are called chemolithotrophs.

Just as prokaryotes can use different sources of energy, they can also utilize different sources of carbon compounds. Recall that organisms that are able to fix inorganic carbon are called autotrophs. Autotrophic prokaryotes synthesize organic molecules from carbon dioxide. In contrast, heterotrophic prokaryotes obtain carbon from organic compounds. To make the picture more complex, the terms that describe how prokaryotes obtain energy and carbon can be combined. Thus, photoautotrophs use energy from sunlight and carbon from carbon dioxide and water, whereas chemoheterotrophs obtain energy and carbon from an organic chemical source. Chemolithoautotrophs obtain their energy from inorganic compounds, while building their complex molecules from carbon dioxide. Table 1 summarizes carbon and energy sources in prokaryotes.