Structures of the bacterial ribosome have provided a framework fo… - Vidyadip

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Structures of the bacterial ribosome have provided a framework for understanding universal mechanisms of protein synthesis. However, the eukaryotic ribosome is much larger than it is in bacteria, and its activity is fundamentally different in many key ways. All ribosomes are composed of two subunits, both of which are built from RNA and protein. Bacterial ribosomes, for example of Escherichia coli, contain a small subunit (SSU) composed of one 16S ribosomal RNA (rRNA) and 21 ribosomal proteins (r-proteins) and a large subunit (LSU) containing 5S and 23S rRNAs and 33 rproteins. In contrast to their bacterial counterparts, eukaryotic ribosomes are much larger and more complex, containing additional rRNA in the form of so-called expansion segments (ES) as well as many additional r-proteins and r-protein extensions.

(1).Ribosomes are present in
(a) Eukaryotes only
(b) Eukaryotes and prokaryotes
(c) Prokaryotes only
(d) Eukaryotes, prokaryotes and viruses

(2) In 70S ribosomes, ‘S’ stands for
(a) SI unit (b) Solubility factor (c) Svedberg unit (d) all of these

(3) 80 S ribosomes occur in
(a) Eukaryotic cells of animals
(b) Eukaryotic cells of animals and plants
(c) Both Eukaryotic cells and prokaryotic cells
(d) all of these

(4) Ribosomes are made up of
(a) RNA only (b) RNA and proteins (c) RNA, DNA and proteins (d) Nucleic acids, proteins and lipids

(5) Polysomes are
(a) multiple units of ribosomes
(b) attachment of many ribosomes to a common mRNA
(c) attachment of many mRNA to a common ribosome
(d) lysosomal aggregations

✓

Answer

(1 - B), (2 - C), (3 - B), (4 - B), (5 - B)

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