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Viruses - Characteristics of viruses
Viruses are also microscopic, but they are not considered as micro-organism. They behave like non-living when outside host cell, and reproduce only when inside the host cell. you might know microbes only for causing harm to human beings by causing diseases and making us ill. But, the truth is microbes are also beneficial to us in a variety of ways. They help in preparation of several household & industrial products like curd, cake, bread, antibiotics & beverages. They also help the environment acting as decomposers and biofertilizers. They play an important in sewage treatment as well.
Characteristics of viruses
viruses do not show any characteristic of living things.Viruses do not have organised cell structure
Viruses do not respire, feed, grow, excrete, move on their own. Viruses can only reproduce if they enter in a living cell of other organism( host cell). When viruses enter into any living cell it starit behaving like a living thing by carrying out the process of reproduction. Outside the living cell dresses behave as non living thing. Due to all this reasons viruses are considered to be an intermediate form between the living and nonliving.
Structure of virus
Viruses do not have an organisation structure. Viruses are acellular i.e their body has no cellular substances or nucleus. Viruses consist of nuclear material coated with proteins. Viruses typically have one or two strands of DNA or RNA. The Genetic material of virus are covered with a protective coat of protein called as CAPSID.
How viruses grow or how viruses reproduce?
Viruses cannot reproduce by themselves.
The virus attaches itself to a specific host cell or the cell in which it can reproduce. After attaching to the host cell virus injects it’s nuclear material( DNA or RNA) inside the host cell. The nuclear material of virus attaches to the nuclear material of the host cell. The nucleic material of virus take the custody of the manufacturing system of the cell. The host cell ignore its own need and switches to making new viruses. The host cell sometimes destroyed in the process and many of the new viruses are released to infect other host cells.
Advantages of viruses
Even though viruses has lots of disadvantages but some viruses plays very important role in the ecosystem. For example the bacteriophages which are also called as bacterial virus please an important role in Marine Ecology and carbon cycling. Bacteriophages in the sewage has the ability to to kill harmful bacteria and keep the bacteria level in control. Scientist are trying to find out viruses which can be used to kill bacteria, and can be used instead of antibiotics.
Disadvantages of viruses
Viruses have many disadvantages as they are the agent of many diseases. Virus causes diseases too many animals and plants. Human diseases such as common cold, influenza, measles, chicken pox, smallpox are all caused by viruses. HIV or immunodeficiency virus causes AIDS in human beings and some animals.
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Fungi |Characteristic Features of Fungi |Mode of Nutrition in Fungi | Mode of Reproduction in Fungi
Fungi |Characteristic Features of Fungi |Mode of Nutrition in Fungi | Mode of Reproduction in Fungi
You would have seen fungi as a white layer on bread when you leave it outside at room temperature for quite a few days. Fungi get favourable conditions & therefore they grow. But, the same bread when kept inside a refrigerator remains fresh for a longer period of time. Fungi are multicellular e. they are made up of multiple cells They are Heterotrophic (Depend on others for their food). They live in colonies and prefer warm & moist places to grow. They are immobile. Some common examples of fungi are: Yeast, Mushroom, Molds. 1. Organisms of kingdom Fungi have the capacity to become multi-cellular, at some stage of their lives. Some are uni-cellular.
They are Eukaryotic.They have cell walls made up of tough complex sugar called “chitin”.Some of these organisms use decaying organic material as food, so they are called “saprotrophs”. Some require a living protoplasm of a host organism for food, they are called “parasites”. Examples: Yeasts (unicellular), Moulds, and Mushrooms. Some fungal species live in permanent, mutually dependent relationship with blue-green algae (cyanobacteria). This relationship is called as “symbiosis”, and the symbiotic life forms are called “litchens”. We can see litchens as the slow growing, multi-coloured patches on the barks of the trees.
Characteristic features of fungi
Fungi are unicellular or multicellular and filamentous. All fungi are made up of fine threads called hyphae. Fungi are plant like organism. They have cell wall.They lack chlorophyll and that’s why do not perform the process of photosynthesis. Store food in the form of glycogen instead of starch. Examples of fungi are yeast, moulds such as Penicillium, bread mould and aspergillus, mushrooms etc. Study of fungi is called mycology.
Habitat of fungi
Fungi are present everywhere and in any habitat. They are found in deserts, cold regions, sea waters, fresh water, in soil, on plants and animals, human skin etc. They grow best in dark warm moist places.
Mode of nutrition in fungi
Fungi look like plant but they cannot make their own food. Fungi are heterotrophic i.e. they depend upon another organism for their food. Fungi generally follow saprophytic or parasitic mode of nutrition. Saprophytic fungi obtain their nutrients from non-living organic matter, usually dead and decaying plants and animals matter by absorbing soluble organic compounds. Parasitic fungi live in or on other organism and get their nutrients from their host. It generally causes disease or illness to the host.
Mode of reproduction in fungi
The Reproduction of fungi can be either sexual or Asexual. In asexual mode of reproduction fungi reproduce by Fragmentation, Budding. Produces spores. The majority of fungi reproduces asexually.
Advantages of fungi in day to day life and it’s usage
Fungi are decomposers, they are good for the soil and cleaning up the environment. Many fungi are used for the production of antibiotics. For example Penicillium is a fungus which produces antibiotic call penicillin. All mushrooms, including the ones we eat, a large fungi. Yeast is another useful fungus which is used in many fermentation processes.
Disadvantages of fungi
Many saprophytic fungi spoil our food, clothes, leather articles etc. example you me have noticed the cottony growth on leather or stale bread. Eating such food can make you ill. Many fungus can cause human diseases.
Some fungal species produces toxin that affects plants animals and humans.
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Algae | Structure of Algae | Mode of nutrition in Algae | Types of Algae
Algae are unicellular or multicellular:
They are multicellular i.e. Made of multiple cells. They prefer mostly aquatic habitats. Some common examples of protozoa are: Spirogyra, Ulothrix, Chlamydomonas
Structure of algae: Some algal cell join each other to form filaments and some have branches or fronds. Both unicellular and multicellular algae live as individual or in colonies. Algae is being found in different forms, Unicellular forms, Multicellular forms A colonial form- volvox.
Unicellular forms:Examples of unicellular Algae are as follows—
Chalamydomonas: It is a green single Cellular alga. They are generally oval, spherical or peared shape. Flagella is used for locomotion.
Habitat of algae: Algae live mostly in an aquatic environment floating on the water. Many times they are found in ponds, lakes and seawater. Some algae leave on bark of tree and some on moist soil and rocks. Some Algae are also found in snow and some in hot spring.
Mode of nutrition in Algae: Algae are considered autotrophs as all of them have chlorophyll in it. Most Algal groups are considered photoautotrophs, they depend entirely upon their photosynthetic Apparatus for their food production, using sunlight as a source of energy and CO2 as a source of carbon to produce their own food. Many of the algae have a symbiotic relationship with plants and animals.
Types of Algae
On the basis of the pigment found cell they are classified into following groups
Blue green Algae: They have blue pigment along with chlorophyll. Nucleus is not present in blue green algae. They are more like bacteria. And therefore they are called as Cyanobacteria. They live in freshwater.
Green algae: This contains mainly chlorophyll. They live in freshwater. Green algae (singular: green alga) are photosynthetic algae that are characterized by having chlorophylls a and b as the predominant pigments, thus rendering them green in colour. They store food as starch within plastids. They include the chlorophytes and the charophytes.
Brown algae: Contents brown pigment in addition to chlorophyll. Brown algae generally marine. Many seaweeds are brown algae, which are almost 50 to 60-meter long.
Red algae: Contains red pigments besides chlorophyll. Red algae are generally marine. Red algae, or Rhodophyta, are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing.
Uses of Algae: Algae are the major source of food for fishes, prawns and many aquatic animals. Sea Algae is eaten in many countries. Most of the oxygen in the atmosphere is released by algae. Red algae yield algin, substance used to thicken cosmetics and food items like ice cream, jelly coma chocolates. Agar a solidifying substance obtained from red algae used in microbiological research. Algae also consumes huge amount of carbon dioxide which is good for our ecosystem.
Disadvantages of Algae
Algal blooms can be toxic and it harms aquatic ecosystem and human health.
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