â¢ Medium-grained (1/16 mm to 2 mm) rocks are usually called sandstone. Medium-grained rocks can be composed of quartz grains, feldspar grains (arkose), or rock fragments and clay (graywacke). Sandstone (Photograph by Parvinder Sethi). Medium-sized grains in clastic sedimentary rocks form sandstone. This sample is a quartz sandstone.
Eukaryotes are those organisms in which the cell body contains a nucleus whereas prokaryotes are those organisms in which the cell body does not contain a nucleus. In amoeba, the reproduction is carried out under the instruction of the nucleus thus making it a eukaryote organism.
Organization of DNA in Prokaryotes. DNA are supercoiled, and require ATP and an enzyme topoisomerase to uncoil the DNA. In prokaryotes, DNA are shown in plasmids and nucleoid. Prokaryote cell replicates by binary fission.lasmids. Bacterial chromosomal DNA with plasmid DNA. Bacteria contains a chromosomal DNA as well as a plasmid DNA, independent from the chromosomal DNA and is capable of replicating itself without chromosomal DNA. Plasmids are also found in some eukaryotes.