Last Updated on December 30, 2020 by Sagar Aryal
Bacteria are single-celled microscopic organisms that are characterized by the presence of incipient nucleus and few membrane-less cell organelles.
- Bacteria are diverse in shape, size, and color, and their habitats also vary ranging from soil, water, to the insides of living organisms.
- Bacteria exist in various shapes like cocci, bacillus, or spirilla where the cells are arranged in either chains or clusters.
- There are different groups of bacteria where some are pathogenic while the rest are harmless or even beneficial.
- Pathogenic bacteria have a capsid as the outermost covering which serves the function of protection.
- Based on the staining techniques, bacteria are divided into Gram-positive and Gram-negative bacteria.
- The difference in staining is due to the structural differences in the cell wall of different bacteria.
- The cell wall is made up of peptidoglycan that protects the cell membrane and other organelles inside.
- Inside the cell wall is the cell membrane, which is composed of a phospholipid bilayer with globular proteins.
- The cytoplasm has a membrane-less nucleus and some ribosomes. The genetic material in bacteria is mostly DNA which is not associated with histone proteins.
- Extrachromosomal DNA is also present in some bacteria in the form of a plasmid.
- Reproduction takes place through binary fission, budding, and fragmentation but different methods like transformation, transduction, and conjugation are available for the transfer of genetic materials.
- Bacteria can be either producer (chemoautotrophs) or consumers (heterotrophs) and even decomposers.
Fungi, singular fungus, are eukaryotes that are characterized by the presence of chitin in the cell wall.
- Common fungi include microscopic organisms like molds and yeasts and macroscopic organisms like mushrooms.
- Fungi are heterotrophs that depend on autotrophs for their food and energy indirectly. These organisms absorb their nutrients from secreting digestive enzymes to the environment.
- Fungi are the principal decomposers in the ecosystem which convert complex organic compounds into inorganic compounds.
- Fungi can either be free-living or might exist in a parasitic or symbiotic relationship with other organisms.
- Because fungi are eukaryotic organisms, they have a distinct nucleus surrounded by a nuclear membrane. These are separated from plants on the basis of the presence of chitin in the cell wall and the absence of chlorophyll.
- They also have multiple cell organelles like mitochondria, vesicles, and 80S ribosomes.
- Most fungi grow in the form of a long elongated thread-like structure called hyphae, which can be either septate or aseptate.
- Macroscopic fungi might appear in the form of colonies in culture media which are different in shape size, texture, and color.
- Reproduction in fungi mostly occurs via budding and sporulation. Sporulating fungi form dry spores that are dispersed by wind or other factors.
- Sexual reproduction is possible in fungi that occur through reproductive spores. The haploid spores combine via cell fusion to form a diploid zygote.
- Fungi are further divided into six groups on the basis of the appearance of the spore; Glomeromycota, Ascomycota, Basidiomycota, Chytridiomycota, Blastocladiomycota, and Zygomycota.
- Fungi are essential organisms as most of them are used for the extraction of antimicrobial products for pharmaceutical industries. Similarly, some fungi are edible and can be used as a source of food.
Key Differences (Bacteria vs Fungi)
Basis for Comparison
|Definition||Bacteria are single-celled microscopic organisms that are characterized by the presence of incipient nucleus and few membrane-less cell organelles.||Fungi, singular fungus, are eukaryotes that are characterized by the presence of chitin in the cell wall.|
|Cell Type||All bacteria are prokaryotes.||All fungi are eukaryotes.|
|No. of cells||Bacteria are unicellular organisms with simpler cellular structure.||Most fungi are multicellular with complex cellular structures. Some fungi like yeast might be unicellular.|
|Size||The size of bacteria ranges from 0.5 to 5 µm.||The size of the fungi ranges from 2 to 10 µm.|
|Cell wall||The cell wall of bacteria is made up of peptidoglycan under which a cell membrane is present.||The cell wall of fungi is made up of chitin.|
|Morphology||Bacteria are found to have three distinct shapes viz round (cocci), spiral (Spirilla), and rod-shaped (bacillus).||Fungi are found to have varying shapes, but most of them are spotted in the form of a thread-like structure called hyphae.|
|pH||Bacteria grow best in the neutral environment of pH range 6.5-7.||Fungi mostly prefer a slightly acidic environment with pH value 4-6.|
|Mobility||Some bacteria are motile with flagella.||Fungi are immobile organisms.|
|Nucleus||The genetic material in bacteria is localized in the nuclear region of the cytoplasm.||The genetic material in fungi is localized in the nuclear region.|
|Cell organelles||Bacteria have few membrane-less organelles.||Fungi contain several membrane-bound organelles.|
|Ribosomes||Bacteria like all prokaryotes contain 70S ribosomes. 70S ribosomes consist of 50S and 30S subunits.||Fungi, like all eukaryotes, contain 80S ribosomes. The 80S ribosome is composed of two subunits 60S and 40S.|
|Reproduction||Bacteria reproduce by an asexual method like binary fission.||Fungi reproduce through both asexual and sexual methods. Sexual reproduction takes place through fungal spores.|
|Nutrition||Bacteria can be autotrophs or heterotrophs.|
|Fungi are mostly heterotrophs that feed on dead and decaying matter.|
|Source of energy||Bacteria derive their energy from inorganic matter or organic matter like sugar, protein, or fat.||Fungi obtain their energy from pre-existing organic matter.|
|Respiration||Bacteria perform aerobic and anaerobic respiration.||Most fungi like yeast perform ethanol fermentation or anaerobic respiration.|
|Pili||Some bacteria might have pili.|
|Fungi don’t have pili.|
|Cytoskeleton||Bacteria do not have cytoskeletons like microtubules or microfilaments.||Fungi have both microtubules and microfilaments.|
|Cell cycle||Bacteria have shorter cell cycles ranging from 20 to 60 minutes.||Fungi have longer cell cycles ranging from 12 to 24 hours.|
|Diseases||Diseases like tuberculosis, tetanus, leprosy, typhoid, cholera are caused by bacteria.||Diseases like skin infections, Aspergillosis, Aspergilloma, Histoplasmosis are caused by fungi.|
|Use||Beneficial uses of bacteria include the production of antibiotics and other chemicals.||Beneficial uses of fungi include the production of beer, bread, and antibiotics.|
|Examples||E. coli, Staphylococcus aureus, Salmonella Typhi, Lactobacillus spp., etc.||Saccharomyces cerevisiae, Histoplasma, Aspergillus niger, Agaricus boirus, etc.|
Examples of Bacteria
Escherichia coli (E. coli)
- E. coli is a model microorganism used for various research studies. These organisms are found in multiple environments, and many are found in the lower intestine of human beings and other warm-blooded animals.
- Most varieties of E. coli are harmless, but few might cause mild to severe diarrhea. Some microbes even produce Vitamin K and Vitamin B-12.
- E. coli is a Gram-negative and facultative anaerobe that flourishes at room temperature.
- It is rod-shaped and has short lifecycles which makes it ideal for research studies.
- E. coli are non-sporing and have peritrichous flagella.
- Salmonella Typhi is a pathogenic organism that infects the intestinal tract and blood of humans and other organisms.
- This organism results in the disease ranging from mild typhoid fever to life-threatening septic shock.
- S. Typhi is Gram-negative organisms that are rod-shaped and non-sporing with peritrichous flagella.
- Salmonella enterica serotype Typhi is usually contracted by the ingestion of food or water that is contaminated with the feces of those that carry the organism.
- These are chemotrophs and can obtain energy through oxidation reactions. These are facultative anaerobes that can utilize oxygen to produce energy when available. When oxygen is not available, they perform anaerobic respiration.
Examples of Fungi
- Yeasts are single-celled eukaryotic organisms, most of which are economically important or pathogenic.
- These are mostly found in soil, on plant surfaces and in the sugar-rich fruits and flowers.
- Saccharomyces cerevisiae is the most commonly known and studied yeast that is commonly used as Baker’s yeast in various baking recipes.
- Some are found as microflora on our body like Candida albicans in the vagina. Other pathogenic fungi include Histoplasma and Blastomyces.
- Yeast infections are one of the most common infections in women.
- Yeasts reproduce by budding where the chains of daughter cells mature and detach later.
- Some yeasts can reproduce via fission and Torula is a wild yeast that reproduces by sexual spores.
- Mushrooms are the spore-bearing fruiting body of fungi mostly found on soil or cultivated on its food source.
- The term mushroom is used for fungi with a stem, cap, and gills, but Agaricus bisporus is the standard mushroom.
- The gills of these fungi form spores that help spread fungi for reproduction.
- Edible mushroom has nutritional value and thus are consumed as a source of Vitamin D. Some mushrooms are toxic as they produce toxins as secondary metabolites.
- Some mushrooms are also being studied as possible treatments for diseases and the extraction of polysaccharides, glycoproteins, and proteoglycans having medical properties.
References and Sources
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