Until recently, prokaryotes did not contain linear plasmids or chromosomes, but they have since been discovered in spirochaetes, Gram-positive bacteria, and Gram-negative bacteria. Bacterial linear DNA has been classified into two structural kinds. Each end of linear plasmids from the spirochaete Borrelia has a covalently closed hairpin loop, while each end of linear plasmids from the Gram-positive filamentous Streptomyces has a covalently connected protein. In eukaryotic cells, replicons with comparable structures are more common than in prokaryotes. However, linear genomic architectures are likely more widespread in bacteria than previously thought, and some replicons may be able to switch between circular and linear isomers. The molecular biology of these widely scattered pieces reveals information about the origins of linear DNA in bacteria, including evidence of prokaryote-eukaryotes genetic exchange.
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Foliation
Explanation:
I just searched it. Foliation is layering in rocks, just like kit kats are layered.
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Structure and function of eukaryotic cell
Eukaryotes have following promint components of cell
1. True nucleus:
The nucleus is surrounded by a true membrane called nucleoplasm. Nucleus contain hereditary materials, DNA which control inheritance. It also contain RNA synthesize in nucleolus.
2. Cell wall:
It is present only in plant cell, and contain cellulose, hemicellulose, lignin, suberin etc. It provides mechanical support to plants.
3. Cell membrane:
It is present both in plants and animal cells. It is made from protein, lipids and carbohydrates. It acts as selective permeable membrane and control the movement of molecules in and out of the cell.
4. Mitochondria and chloroplast:
Chloroplast is present only in plant cell. It contains chlorophyll which aid in photosynthesis and prepare glucose.
Mitochondria is present in all eukaryotic cells.cellular respiration occurs in mitochondria and ATP is formed by the break down of glucose.
5. Endoplasmic reticulum and Golgi apparatus:
Endomembrane system of eukaryotic cell is made from a network of tube and sacks connected together forming endoplasmic reticulum and golgi apparatus independently. Endoplasmic reticulum may have attached ribosomes or not and is involved in protein synthesis, while golgi apparatus help in modification, packaging, and transport of proteins through out the cell.
Lysosomes, cytoskeleton, vacoules, peroxisomes, glyoxisomes and other organelles are also present in eukaryotic cell.
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Through the study of meteorites, their chemical composition of silicates—material made of silicon and oxygen. Others contain metal—nickel and iron. Knowing what the meteorite was composed of lets you know where it came from. Chondrites are composed of hardened lava - this is occurred at the beginning of the solar system (4.5 mya). Carbonaceous chondrites contain carbon and water which formed away from the sun.
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