1.
Submitted to : Submitted by:
Dr. Mithilesh Kumar Vishnu Kumar
Dr. Vipul Jha AB & MB

2.
Questions & Facts
1. Why are eukaryotic ribosomes 80S when prokaryotic ribosomes
are 70S?
2. Are there functional differences between free ribosomes and
endoplasmic reticulum ribosomes?
3. In the text it says: " In the nucleolus, new ribosomal RNA is
transcribed from the DNA, and it combines with proteins from
the cytoplasm to form the subunits of the ribosome. Where they
can combine to form ribosomes and carry out their job of making
proteins.
4. How we can say that ribosome work as enzyme?
5. Hibernating 100S ribosomes help bacteria survive (SLU
Scientist: Disrupting staph's naps may lead to new antibiotics.

3.
Ribosome
Macromolecular structures of rRNA + rProtein, is called
( Ribonucleoprotein).
 Protein producing structure organelles
Site of origin nucleolus
Large amount requirement for protein synthesis.
Some eukaryotic organisms contains up to four nucleoli
Nucleoli are site specific genetic loci called nucleolar
organizing regions (NORs)
NORs contain tandem repeats of rRNA genes
Human genome contains more than 200 clustered copies of
the rRNA gene on five different chromosome(13, 14, 15,
21, 22).

4.
 It is a large & complex molecule.
 Found in all living cells prokaryote & eukaryote.
 That serves as the primary site of biological protein
synthesis.
 Ribosome was first observed in 1953s by romanian
cell biologist george emil palade using a electrone
microscope.
 In prokaryote free form in cytoplasm & protoplasm.
 In eukaryote free in cytoplasm inside the cell attach to
the outer membrane in endoplasmic reticulum

5.
Discovery
Ribosomes were first observed in the mid-1950s
by Romanian-American cell biologist George Emil
Palade, using an electron microscope, as dense particles
or granules.
 The term "ribosome" was proposed by scientist
Richard B. Roberts in the end of 1950s.
 In prokaryote free form in cytoplasm & protoplasm.
In eukaryote free in cytoplasm inside the cell attach to
the outer membrane in endoplasmic reticulum

6.
Structure

7.
Structure of 16s RNA

8.
BIOGENESIS OF rRNA
1. Prokaryotic cell 3 rRNA in e.coli are transcribed
from a single gene. 7 copies of gene occur in
genome. A single transcript is produced in mature
rRNA.processing of RNA folding, attachment of
rProtein, methylation of bases & cleavage by
Ribonuclease.
2. Eukaryotic cell
single gene arranged in multiple copies as clusters
series.Transcribed in nucleolus by polymerase-I.
5S rRNA is transcribed in cytoplasm by
polymerase III.