LIFE CYCLE OF BACTERIOPHAGES ( LYTIC AND LYSOGENIC CYCLE)

The bacteriophage replicates only inside the bacterial cell. There are many steps in replication. Attachment (Adsorption) of Phage to the Host Cell: First of all the bacteriophage attaches to the bacterial cell at receptor site. The receptor sites are present on the cell wall of bacterium. During attachment, week chemical union occurs between virion and the receptor site. Penetration: In ...

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Diseases Caused by Viruses

DISEASES CAUSED BY VIRUSES Small Pox: Virus: It is caused by poxviruses. This virus is DNAenveloped. History: This disease occurred as epidemic in China in 12th century B.C. Until the early 20th century, it was common. Symptoms / Effects: This disease results in the formation of raisedfluid-filledvesicles on the body. These become pustules later on and form pitted scars, the ...

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Structure and Shape of bacteriophage

These have two shapes (structural forms): Cubical: These are regular solid or icosahedral (having 20 triangular faces). Helical Symmetry: They are rod shaped. Many phages consist of head and tail. The heads are polyhedral but tails are rod shaped. STRUCTURE OF BACTERIOPHAGE Bacteriophage meaning bacteria eater. Earlier workers studied few phages that infect Escherichia coli. Of these the best phages ...

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facts about cells 11 graders

ADDITIONAL RELATED READINGS ABOUT CELL A cell is the structural and functional unit of life. Discovery of cell is linked with the invention of microscope because most of the cells are microscopic. Robert Hooke discovered the cell in 1665 under his self-made compound microscope. According to Hooke, cell is an empty space surrounded by thick walls. He published his work ...

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Leptosporangium vs Eusporangium

Leptosporangium vs Eusporangium – In the first step in leptosporangium, the epidermal cells of leaf or sporangiophore some sperm cells behave as superficial initial cells. Superficial initial cell divides periclinally due to which to form two celled body structures. Secondly, the outer cell as sporangial initial cell and inner cell that does not take part in further division as stalk ...

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Sporangium and Different Spore Types

Sporangium Sporangium has been derived from modern Latin word “spora” means spores and classical Greek word “angeion” which means vessel. So, sac like structure, which develops spores as tetrad after meiosis of spore mother cell. Spore: Reproductive unit of a plant body which upon germination to form a new plant body. Types of Sporangium (Depending upon Organization with Position, Shape, ...

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Female Cone Lecture

Female Cone Female cone has whorl of loosely arranged megasporophylls. In cycas, whereas in pinus there is in compact arrangement of megasporophylls, behave ovuliferous scale. So, in pinus female cone behave as inflorescence due to aggregation of female flower (ovuliferous scale). Each megasporophyll quite large in size, bearing 1-5 pairs of big ovules of cycas whereas, in pinus there are ...

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Virus Lecture Notes

Virus The term virus was coined by Pasture. For the discovery of viruses’ first-time work was performed by a scientist Iwanowsky, who was discovered TMV (tobacco mosaic virus). it was later crystallized by a scientist Stanley. Now another scientist Beijuinuk called ‘viruses as “Contagium Vivum Fluidum”. What that mean? Living infectious fluid. As today we know viruses are passed in ...

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Quantitative Characters of Plant Community

Attributes of Community Quantitative characters of plant community – A collection of organisms interacting directly or indirectly is a community. Within the community some species carry out similar functions or exploit the same resources. These groups are called guilds. For example, birds feeding mostly on insects make up an insect-feeding guild. A community may be autotrophic when it includes photosynthetic ...

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Reproductive Strategies

Reproduction and Reproductive Strategies in Plants Reproductive Strategies – Reproduction is the major drive of all living things. The role of the reproductive drive is to transmit genetic characteristics from one generation to another. The ability of organism to leave behind reproducing offspring is it fitness. Achieving fitness involves among other things, fecundity and survivorship, physiological adaptations, modes of reproduction, ...

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