Is extra genomic DNA present in prokaryotes and eukaryotes? If yes, indicate their location in both the types of organisms.
Yes, .extra genomic DNA is present in both prokaryotes and eukaryotes. In prokaryotes, extra genomic DNA is present in form of plasmids and as mitochondria and plastids in eukaryotes.
In Prokaryotes plasmids are self replicating, extra chromosomal segments of double stranded, circular, naked DNA. Plasmids provide unique phenotypic characters to bacteria. They are independent of main nucleoid. Some of them contain important genes like fertility factor, nif genes and resistance factors. Plasmids are used as vectors in genetic engineering.
In Eukaryotes : mtDNA (mitochondrial DNA) and cpDNA (chloroplast DNA) are present as a extra genomic DNA in mitochondria and chloroplast respectively. Mitochondria have their own naked, circular or linear DNA which can replicate independently. Mitochondrial DNA produces its own mRNA, fRNAand rRNA. Plastids are another semi-autonomous organelles having DNA and double membrane envelope which store or synthesise various types of organic compounds. Chloroplast DNA is naked, circular or occasionally linear.
Give the biochemical composition of plasma membrane. How are lipid molecules arranged in the membrane?
The genomic content of the nucleus is constant for a given species where as the extra chromosomal DNA is found to be variable among the members of a population. Explain.
Are the different types of plastids interchangable? If yes, give examples where they are getting converted from one type to another.
Structure and function are correctable in living organisms. Can you justify this by taking plasma membrane as an example?
Are the different types of plastids interchangable? If yes, give examples where they are getting converted from one type to another.
Is there a species specific or region specific type of plastids? Flow does one distinguish one from the other?
Discuss briefly the role of nucleolus in the cells actively involved in protein synthesis.
Is extra genomic DNA present in prokaryotes and eukaryotes? If yes, indicate their location in both the types of organisms.
Write the functions of the following
(a) Centromere (b) Cell wall
(c) Smooth ER (d) Golgi apparatus
(e) Centrioles
Eukaryotic cells have organelles which may
(a) not be bound by a membrane
(b) bound by a single membrane
(c) bound by a double membrane
Group the various sub-cellular organelles into these three categories.
Briefly give the contributions of the following scientists in formulating the cell theory.
(a) Rudolf Virchow
(b) Schleiden and Schwann
Differentiate between Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER).