Collegedunia Team Content Curator
Content Curator
Archaea and Bacteria are microorganisms that belong to the category of Prokaryotes and are unicellular organisms. In this article, we will be covering the key difference between Archaea and Bacteria. DNA sequence along with structural and functional comparison divides all living organisms into three primary categories: Bacteria, Archaea and Eukaryotes. But there are exceptions, all Archaea and Bacteria are not prokaryotes. Nucleus and membrane found organelles are not present in Archaea and Bacteria.
Explore more: Eukaryotes
| Table of Content |
Key Terms: Bacteria, Archaea, Prokaryotes, Eukaryotes, Phototrophs, Methanogens, Reproduction, Gram-positive, Gram-negative, PseudoPeptidoglycan, Peptidoglycan, Flagella, Glucose Oxidation, RNA Polymerase, Pathogenicity
Definition of Archaea
[Click Here for Sample Questions]
Archaea are single celled organisms which have unique properties that differentiate them from bacteria and Eukaryotes. They lack cell nuclei and therefore come under the category of prokaryotes. These organisms inhabit extreme environments—saline water, deep-sea vents, hot springs, and also below petroleum deposits.
Archaea obtain energy from various sources like carbon dioxide, acetate, ammonia, sulfur, and even sunlight. The group of Archaea using sunlight as the source of energy are known as phototrophs. Oxygen-generated photosynthesis is not performed by these organisms. Another form of Archaea that derives energy from ammonia and sulfur includes anaerobic methane oxidizers, nitrifiers, and methanogens.
Archaea have membrane lipids with fatty acid linked to glycerol by ether bond instead of ester bond only like in bacteria and eukaryotes. And reproduction in these organisms is asexual— budding, fragmentation, and fission.
Definition of Bacteria
[Click Here for Previous Year Questions]
Bacteria are single cell prokaryotes that form domains of organisms depending on shape, size, habitat, and structure. They are membrane and less cell organelles, hence they are simple in structure and functions. They are the smallest entities in the world, thus microscopic.
The staining technique is used to divide bacteria into Gram-positive and Gram-negative. Cell walls of most bacteria are made of peptidoglycan which protects them from harmful chemicals. The cytoplasm has ribosomes and the incipient nucleus without membrane contains the genetic material.
Reproduction takes place by binary fission, budding, and fragmentation through different methods like transduction, conjugation, and transformation.
Do Check :
| Chapter Related Topics | ||
|---|---|---|
| Biological Classification | Two Kingdom Classification | economic importance of fungi |
| Mycology | Components of Ecosystem | where do microorganisms live |
Some bacteria are beneficial for antibiotic production, biochemical cycles, and industrial use. But some pathogenic organisms can lead to diseases.
Differences Between Archaea and Bacteria
[Click Here for Sample Questions]
| Comparison | Archaea | Bacteria |
|---|---|---|
| Habitat | Archaea are extremophiles, found in extreme environments like the deep sea, hot springs and salt brine, etc. | Bacteria are found in different environments, from the soil, water, and even inside living and non-living things. |
| Cell wall | Their cell wall is made up of pseudo peptidoglycan and lacks D-amino acids and N-acetylmuramic acid. | Their cell wall is made up of peptidoglycan consisting of N-acetylmuramic acid and D-amino acids. |
| Glucose oxidation | They follow modified metabolic pathways of the Embden–Meyerhof, and Entner–Doudoroff pathways | They follow Glycolysis and Kreb’s cycle are metabolic pathways for glucose oxidation. |
| Photosynthesis | They don’t synthesize oxygen-generating photosynthesis, but they are phototrophs. | Many bacteria contain photosynthetic pigments that help in photosynthesis. |
| Types | Methanogens, Thermophiles and Halophiles | Gram-positive and Gram-negative. |
| Flagella | Archaella is formed by adding subunits at the base. | Their flagella are hollow and add subunits in the direction from the central pore towards the tip of the flagella. |
| Reproduction | They reproduce by budding, fragmentation, and fission. | Few bacteria form spores that helps them survive in extreme conditions. |
| tRNA | Thymine is absent in the tRNA. | Thymine is present in the tRNA. |
| Chromosomes | Introns are present | Introns are absent. |
| RNA polymerase | It is complex with more than eight polypeptides. They can even have multiple RNA polymerases. | It is simple, with four polypeptides. |
| Pathogenicity | Non-pathogenic. | Pathogenic and non-pathogenic. |
| Examples | Staphylothermus marinus and Sulfolobus tokodaii. | Bacillus subtilis and Staphylococcus aureus. |
Examples of Archaea and Bacteria
[Click Here for Previous Year Questions]
Examples of Archaea are explained below:
Methanogens: Mathogens produce methane during metabolic activities. These are mostly found in wetlands and gastrointestinal tract of ruminants and even humans. More than 50 species of methanogens are known so far, which are used for wastewater treatments as it is cost-effective and time-saving. Methanosarcina bakeri, Methanosarcina acetivorans, and Methanococcus maripaludis are examples of methanogens.
Sulfolobus: They are acidophilic and thermophilic in nature. Sulfolobus grow at temperatures around 800C and PH 2-3. They utilize sulfur as their final electron acceptor during cellular respiration. These species are autotrophic and heterotrophic as their mode of nutrition is dependent on sulfur. Sulfolobus tokodaii and Sulfolobus metallicus are examples of sulfolobus.
Examples of Bacteria are explained below:
Lactobacilli: They are rod-shaped, gram-positive, and non-spore-forming microorganisms. Lactobacilli produce lactose as a by-product of glucose metabolism and are are found in milk and milk products. These organisms are also found in the intestine of human beings. Lactobacillus brevis, Lactobacillus casei, and Lactobacillus plantarum are examples of Lactobacilli.
Escherichia coli (E.coli): Escherichia coli are found in multiple environments, many of them are found in the human intestine and in other warm-blooded animals. E.coli are rod-shaped and have a short life cycle. They are harmless, and may cause mild fever or diarrhea. Some of the microbes produce vitamin K and vitamin B-12. They don’t produce spores and possess peritrichous flagella.
Do Check Out :
| Important Topics | ||
|---|---|---|
| fungus life cycle | difference between rust and smut | difference between fungi and lichens |
| Cyanobacteria | Heterotrophic Bacteria | Saprophytes |
| What are Lichens? | Mycorrhiza | Prions |
Things to Remember
- Archaea and Bacteria are microorganisms that belong to the category of Prokaryotes and are unicellular organisms.
- Nucleus and membrane found organelles are not present in Archaea and Bacteria.
- Archaea obtain energy from various sources like carbon dioxide, acetate, ammonia, sulfur, and even sunlight. The group of Archaea using sunlight as the source of energy are known as phototrophs.
- Another form of Archaea that derives energy from ammonia and sulfur includes anaerobic methane oxidizers, nitrifiers, and methanogens.
- The staining technique is used to divide bacteria into Gram-positive and Gram-negative. Cell walls of most bacteria are made of peptidoglycan which protects them from harmful chemicals.
Also read: Two Kingdom Classification
Previous year Questions
- Match Column - I with Column - II. Column - 1 Column - II..[NEET 2019]
- Bacteria lack alternation of generation because there is..[NEET 1991]
- Bacterial leaf blight of rice is caused by a species….[NEET 2008]
- Barophilic prokaryotes...[NEET 2005]
- BGA (blue green algae) are included in which of the following groups?..[NEET 1996]
- Ciliates differ from all other protozoans in.[NEET 2018]
- Curing of tea leaves is brought about by the activity of -….[NEET 2006]
- Which one of the following is wrong for fungi ?..[NEET 2016]
- Which one of the following is a slime mould?...[NEET 2007]
- Which one of the following organisms is not an example of eukaryotic cells ?….[NEET 2011]
- Which one of the following fungi contains hallucinogens?...[NEET 2014]
- Which one of following is used as vector for cloning genes into higher organisms ?...[NEET 2010]
- Which one belongs to monera?.[NEET 1990]
- Which of the following shows coiled RNA strand and capsomeres?….[NEET 2014]
- Which of the following organisms are known as chief producers in the oceans ?..[NEET 2018]
- Which of the following is free-living aerobic and non-photosynthetic nitrogen-fixing bacterium?..[NEET 1997]
- Which of the following is a symbiotic nitrogen fixer?…..[NEET 2009]
- Which one of the following does not belong to kingdom-Monera?...[KCET 2013]
- Which of the following groups of algae do not have eukaryotic organization ?….[KCET 2005]
Sample Questions
Ques. What are forms of Photosynthesis among Archaea and bacteria? (2 Marks)
Ans.
- The light activates a pigment that transports protons across a membrane, driving the synthesis of ATP via chemiosmosis.
- Geothermal radiation is used instead of light.
- Light can be absorbed by pigments that raise electrons to high energy states then cellular respiration occurs.
Ques. Draw and label a prokaryotic cell. (3 Marks)
Ans.
Ques. What are methanogens? (3 Marks)
Ans. Methanogens are prokaryotes belonging to the domain Archaea. These are found mostly in wetlands and in gastrointestinal tracts of various ruminants and even human beings. Some methanogens are extremophiles, thus found in hot springs and deep-sea vents. There are more than 50 species of methanogens discovered, most of which produce methane by different metabolic pathways.
Some methanogens reduce carbon dioxide in the presence of hydrogen to produce methane. Others produce methanol through anaerobic respiration. Methanogens are used in the treatment of wastewater for bio composition, as it is cost-effective and time-saving. A few common methanogens are Methanosarcina bakeri, Methanosarcina acetivorans, and Methanococcus maripaludis.
Ques. Write a short note on Archaea. (3 Marks)
Ans. Archaea are single celled organisms which have unique properties that differentiate them from bacteria and Eukaryotes. They lack cell nuclei and therefore come under the category of prokaryotes. These organisms inhabit extreme environments, like saline water, deep-sea vents, hot springs, and also below petroleum deposits. Archaea obtain energy from various sources like carbon dioxide, acetate, ammonia, sulfur, and even sunlight.
The group of Archaea using sunlight as the source of energy are known as phototrophs. Oxygen-generated photosynthesis is not performed by these organisms. Another form of Archaea that derives energy from ammonia and sulfur includes anaerobic methane oxidizers, nitrifiers, and methanogens. Archaea have membrane lipids with fatty acid linked to glycerol by ether bond instead of ester bond only like in bacteria and eukaryotes. And reproduction in these organisms is asexual, by budding, fragmentation, and fission.
Ques. Give the difference between Archaea and Bacteria. (4 Marks)
Ans.
| Archaea | Bacteria |
|---|---|
| Archaea are extremophiles, found in extreme environments like the deep sea, hot springs and salt brine, etc. | Bacteria are found in different environments, from the soil, water, and even inside living and non-living things. |
| Their cell wall is made up of pseudo peptidoglycan and lacks D-aminoacids and N-acetylmuramic acid. | Their cell wall is made up of peptidoglycan consisting of N-acetylmuramic acid and D-amino acids. |
| They follow modified metabolic pathways of the Embden–Meyerhof, and Entner–Doudoroff pathways | They follow Glycolysis and Kreb’s cycle are metabolic pathways for glucose oxidation. |
| They don’t synthesize oxygen-generating photosynthesis, but they are phototrophs. | Many bacteria contain photosynthetic pigments that help in photosynthesis. |
| Methanogens, Thermophiles and Halophiles | Gram-positive and Gram-negative. |
| Archaella are formed by adding subunits at the base. | Their flagella are hollow and add subunits in the direction from the central pore towards the tip of the flagella. |
| They reproduce by budding, fragmentation, and fission. | Few bacteria form spores that help them survive in extreme conditions. |
| RNA polymerase is complex with more than eight polypeptides. They can even have multiple RNA polymerases. | RNA polymerase is simple, with four polypeptides. |
Ques. What is bacteria? Give two examples. (5 Marks)
Ans. Bacteria are single cell prokaryotes that form domains of organisms depending on shape, size, habitat, and structure. They are membrane and less cell organelles, hence they are simple in structure and functions. They are the smallest entities in the world, thus microscopic. The staining technique is used to divide bacteria into Gram-positive and Gram-negative.
Cell walls of most bacteria are made of peptidoglycan which protects them from harmful chemicals. The cytoplasm has ribosomes and the incipient nucleus without membrane contains the genetic material. Reproduction takes place by binary fission, budding, and fragmentation through different methods like transduction, conjugation, and transformation. Some bacteria are beneficial for antibiotic production, biogeochemical cycles, and industrial use. But some pathogenic organisms can lead to diseases.
Lactobacilli: They are rod-shaped, gram-positive, and non-spore forming microorganisms. They produce lactose as a by-product of glucose metabolism. They are found in milk and milk products. These organisms are also found in the intestine of human beings.
Escherichia coli (E.coli): They are found in multiple environments, many of them are found in the human intestine and in other warm blooded animals. They are rod-shaped and have a short life cycle. They are harmless, may cause mild fever or diarrhea. Some of the microbes produce vitamin K and vitamin B-12. They don’t produce spores and possess peritrichous flagella. They are Gram-negative, facultative anaerobes and they grow at room temperature.
Ques. Write the difference between gram-positive bacteria and gram-negative bacteria. (5 Marks)
Ans.
| Gram-positive bacteria | Gram-negative bacteria |
|---|---|
| The cell wall is single-layered and smooth. | The cell wall is double-layered and wavy. |
| The thickness of the cell wall is 20 to 80 nanometres | The thickness of the cell wall is 8 to 10 nanometres |
| The peptidoglycan layer is thick and can be multilayered | The peptidoglycan layer is thin and often single-layered. |
| They are cocci or spore-forming rods | They are non-spore-forming rods. |
| The flagella structure has two rings in the basal body | The flagella structure has four rings in the basal body |
| Exotoxins are produced by them. | Endotoxins or Exotoxins are produced by them. |
| Gram-positive bacteria retain the crystal violet color even after they are washed with acetone/ alcohol. Hence they appear purple-colored under the microscope after gram staining. | Gram-negative do not retain the stain color even after they are washed with acetone/alcohol and appear as pink-colored under the microscope after gram staining. |
Ques. Give the difference between eukaryotes and prokaryotes. (5 Marks)
Ans.
| Prokaryotes | Eukaryotes |
|---|---|
| They are unicellular organism | They are unicellular and multi-cellular |
| The cell size ranges from 0.2 μm – 2.0 μm in diameter | The cell size ranges from 10 μm – 100 μm in diameter |
| The cell was is usually present and is chemically complex in nature | When a cell wall is present, it is chemically simple in nature |
| Ribosomes are smaller in size and spherical in shape | Ribosomes are comparatively larger in size and linear in shape |
| DNA arrangement is Circular | DNA arrangement is Linear |
| Cell division through binary fission | Cell division through mitosis |
| Reproduction is asexual | Reproduction is both asexual and sexual |
| The flagella are smaller in size | The flagella are larger in size |
| Example: Bacteria and Archaea | Example: Plant and Animal cell |
Do Check Out:
Comments