Briefly give the contributions of the following scientists in formulating the cell theory.
(a) Rudolf Virchow
(b) Schleiden and Schwann
(a) Rudolf Virchow – Rudolf Virchow proposed theory of cell lineage, Omnis cellula-e cellula, cells develop by division of
pre-existing cells.
(b) Schleiden and Schwann:- In 1838, Matthias Schleiden, a German botanist observed that all plants are composed of different kinds of cells, which form the tissues of the plant. At the same time, Theodore Schwann (1839), a British zoologist studied different types of animal tissues including development of embryos. He found that animal cells lack a cell wall, but they are covered by a membrane. Otherwise cells of both plants and animals are similar. Schwann proposed the hypothesis that bodies of animals and plants are composed of cells and products of cells. Both scientist Schleiden and Schwann together gave cell theory. This theory states that bodies of all living organisms are made up of cells and their products. All cells are basically alike in their chemical composition and physiology. Activities of an organism are the sum total of activities and interactions of its constituent cells.
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.
Write the functions of the following
(a) Centromere (b) Cell wall
(c) Smooth ER (d) Golgi apparatus
(e) Centrioles
Is extra genomic DNA present in prokaryotes and eukaryotes? If yes, indicate their location in both the types of organisms.
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).