RNA has several types that perform different functions in the cell. Messenger RNA (mRNA) carries genetic information from DNA to the ribosomes for protein synthesis. Transfer RNA (tRNA) transfers amino acids to the ribosome during protein synthesis by binding to mRNA codons through complementary base pairing. Ribosomal RNA (rRNA) is the major constituent of ribosomes and plays key roles in protein synthesis such as catalyzing peptide bond formation. The different RNA types have distinct structures that enable their functions.
The flow of information in the cell starts at DNA, which replicates to form more DNA. Information is then ‘transcribed” into RNA, and then it is “translated” into protein.
Information does not flow in the other direction.
A few exceptions to the Central Dogma exist
some RNA viruses, called “retroviruses”.
Eukaryotic transcription is the elaborate process that eukaryotic cells use to copy genetic information stored in DNA into units of RNA replica.- Source: Wikipedia
RNA transport
Multiple classes of RNA are exported from the nucleus
Transportation through nuclear pore complex.
Ribosomal subunits are assembled in the nucleolus and exported by exportin 1
tRNAs are exported by a dedicated exportin
Messenger RNAs are exported from the nucleus as RNA-protein complexes
Messenger RNAs are exported from the nucleus as RNA-protein complexes
hnRNPs move from sites of processing to NPCs
Precursors to microRNAs are exported from the nucleus and processed in the cytoplasm
RNA Polymerase
Introduction
Purification
History
PRODUCTS OF RNAP
Messenger RNA
Non-coding RNA or "RNA genes
Transfer RNA
Ribosomal RNA
Micro RNA
Catalytic RNA (Ribozyme)
prokaryotic and eukaryotic
Transcription by RNA Polymerase
TYPES OF RNA POLYMERASE
Type I
Type II
Type III
Prokaryotic Transcription Unit
EXPRESSION OF A PROKARYOTIC GENE
Prokaryotic Polycistronic Message Codes for Several Different Proteins
Eukaryotic Transcription Unit
ENHANCERS AND SILENCERS
RESULT OF THE TRANSCRIPTION CYCLE
RNAP III TRANSCRIBES HUMAN MICRORNAS
RNAP I–specific subunits promotepolymerase clustering to enhance the rRNA genetranscription cycle
RNAP II–TFIIB STRUCTURE ANDMECHANISM OF TRANSCRIPTION INITIATION
FIVE CHECKPOINTS MAINTAINING THE FIDELITY OFTRANSCRIPTION BY RNAP IN STRUCTURAL ANDENERGETIC DETAILS
The flow of information in the cell starts at DNA, which replicates to form more DNA. Information is then ‘transcribed” into RNA, and then it is “translated” into protein.
Information does not flow in the other direction.
A few exceptions to the Central Dogma exist
some RNA viruses, called “retroviruses”.
Eukaryotic transcription is the elaborate process that eukaryotic cells use to copy genetic information stored in DNA into units of RNA replica.- Source: Wikipedia
RNA transport
Multiple classes of RNA are exported from the nucleus
Transportation through nuclear pore complex.
Ribosomal subunits are assembled in the nucleolus and exported by exportin 1
tRNAs are exported by a dedicated exportin
Messenger RNAs are exported from the nucleus as RNA-protein complexes
Messenger RNAs are exported from the nucleus as RNA-protein complexes
hnRNPs move from sites of processing to NPCs
Precursors to microRNAs are exported from the nucleus and processed in the cytoplasm
RNA Polymerase
Introduction
Purification
History
PRODUCTS OF RNAP
Messenger RNA
Non-coding RNA or "RNA genes
Transfer RNA
Ribosomal RNA
Micro RNA
Catalytic RNA (Ribozyme)
prokaryotic and eukaryotic
Transcription by RNA Polymerase
TYPES OF RNA POLYMERASE
Type I
Type II
Type III
Prokaryotic Transcription Unit
EXPRESSION OF A PROKARYOTIC GENE
Prokaryotic Polycistronic Message Codes for Several Different Proteins
Eukaryotic Transcription Unit
ENHANCERS AND SILENCERS
RESULT OF THE TRANSCRIPTION CYCLE
RNAP III TRANSCRIBES HUMAN MICRORNAS
RNAP I–specific subunits promotepolymerase clustering to enhance the rRNA genetranscription cycle
RNAP II–TFIIB STRUCTURE ANDMECHANISM OF TRANSCRIPTION INITIATION
FIVE CHECKPOINTS MAINTAINING THE FIDELITY OFTRANSCRIPTION BY RNAP IN STRUCTURAL ANDENERGETIC DETAILS
RNA- A polymer of ribonucleotides, is a single stranded structure. There are three major types of RNA- m RNA,t RNA and r RNA. Besides that there are small nuclear,micro RNAs, small interfering and heterogeneous RNAs. Each of them has a specific structure and performs a specific function.
RNA is a ribonucleic acid that helps in the synthesis of proteins in our body. This nucleic acid is responsible for the production of new cells in the human body. It is usually obtained from the DNA molecule.
Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation, and expression of genes. RNA and DNA are nucleic acids, and, along with proteins and carbohydrates, constitute the four major macromolecules essential for all known forms of life. Like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA it is more often found in nature as a single-strand folded onto itself, rather than a paired double-strand.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
4. Differences between RNA and DNA
S.No. RNA DNA
1) Single stranded mainly except
when self complementary
sequences are there it forms a
double stranded structure (Hair
pin structure)
Double stranded (Except for
certain viral DNA s which are
single stranded)
2) Ribose is the main sugar The sugar moiety is deoxy
ribose
3) Pyrimidine components differ.
Thymine is never found(Except
tRNA)
Thymine is always there but
uracil is never found
4) Being single stranded structure-
It does not follow Chargaff’s rule
It does follow Chargaff's rule.
The total purine content in a
double stranded DNA is always
equal to pyrimidine content.
4Biochemistry For Medics
5. Differences between RNA and DNA
S.No. RNA DNA
5) RNA can be easily destroyed by
alkalies to cyclic diesters of
mono nucleotides.
DNA resists alkali action due to
the absence of OH group at 2’
position
6) RNA is a relatively a labile
molecule, undergoes easy and
spontaneous degradation
DNA is a stable molecule. The
spontaneous degradation is
very slow. The genetic
information can be stored for
years together without any
change.
7) Mainly cytoplasmic, but also
present in nucleus (primary
transcript and small nuclear
RNA)
Mainly found in nucleus, extra
nuclear DNA is found in
mitochondria, and plasmids
etc
8) The base content varies from
100- 5000. The size is variable.
Millions of base pairs are there
depending upon the organism
5Biochemistry For Medics
6. Differences between RNA and DNA
S.No. RNA DNA
9) There are various types of RNA –
mRNA, r RNA, t RNA, Sn RNA, Si
RNA, mi RNA and hn RNA. These
RNAs perform different and
specific functions.
DNA is always of one type and
performs the function of
storage and transfer of genetic
information.
10) No variable physiological forms
of RNA are found. The different
types of RNA do not change
their forms
There are variable forms of
DNA (A to E and Z)
11) RNA is synthesized from DNA, it
can not form DNA(except by the
action of reverse transcriptase).
It can not duplicate (except in
certain viruses where it is a
genomic material )
DNA can form DNA by
replication, it can also form
RNA by transcription.
12) Many copies of RNA are present
per cell
Single copy of DNA is present
per cell.
6Biochemistry For Medics
7. Types of RNA
In all prokaryotic and eukaryotic organisms,
three main classes of RNA molecules exist-
1) Messenger RNA(m RNA)
2) Transfer RNA (t RNA)
3) Ribosomal RNA (r RNA)
4) heterogeneous nuclear RNA (hnRNA).
The other are small RNAs:
o small nuclear RNA (SnRNA),
o micro RNA(mi RNA) and
o small interfering RNA(Si RNA) and
7Biochemistry For Medics
8. Messenger RNA (m-RNA)
Comprises only 5% of the RNA in the cell
Most heterogeneous in size and base sequence
All members of the class function as
messengers carrying the information in a gene to
the protein synthesizing machinery
8Biochemistry For Medics
9. Structural Characteristics of
m-RNA
The 5’ terminal end is capped by 7-
methyl guanosine triphosphate cap.
The cap is involved in the
recognition of mRNA by the
translating machinery
It stabilizes m RNA by protecting it
from 5’ exonuclease
9Biochemistry For Medics
10. Structural Characteristics of
m-RNA(contd.)
The 3’end of most m-RNAs have a polymer of
Adenylate residues( 20-250)
The tail prevents the attack by 3’ exonucleases
Histones and interferons do not contain poly A
tails
On both 5’ and 3’ end there are non coding
sequences which are not translated (NCS)
The intervening region between non coding
sequences present between 5’ and 3’ end is
called coding region. This region encodes for the
synthesis of a protein.
10Biochemistry For Medics
12. Structural Characteristics of
m-RNA(Contd.)
The m- RNA molecules are formed with the help of
DNA template during the process of transcription.
The sequence of nucleotides in m RNA is
complementary to the sequence of nucleotides on
template DNA.
The sequence carried on m -RNA is read in the form
of codons starting from 5’ end.
A codon is made up of 3 nucleotides
The m-RNA is formed after processing of
heterogeneous nuclear RNA
12Biochemistry For Medics
13. Heterogeneous nuclear RNA
(hnRNA)
In mammalian nuclei , hnRNA is the
immediate product of gene transcription
The nuclear product is heterogeneous in size
(Variable) and is very large.
Molecular weight may be more than 107, while
the molecular weight of m RNA is less than 2x 106
75 % of hnRNA is degraded in the nucleus,
only 25% is processed to mature
m RNA
13Biochemistry For Medics
14. Heterogeneous nuclear RNA
(hnRNA)
Mature m –RNA is formed from primary transcript by
capping, tailing, splicing and base modification.
14Biochemistry For Medics
15. Biochemistry For Medics 15
Transfer RNA (t- RNA)
Transfer RNA are the smallest of three major species
of RNA molecules
They have 74-95 nucleotide residues
They are synthesized by the nuclear processing of a precursor
molecule
They transfer the amino acids from cytoplasm to the
protein synthesizing machinery, hence the name t
RNA.
They are easily soluble , hence called “Soluble RNA or s
RNA
They are also called Adapter molecules, since they act as adapters for
the translation of the sequence of nucleotides of the m RNA in to
specific amino acids
There are at least 20 species of t RNA one
corresponding to each of the 20 amino acids
required for protein synthesis.
16. Structural characteristics of t- RNA
1) Primary structure-sequence of nucleotides.
The nucleotide sequence of all the t RNA
molecules allows extensive intrastand
complimentarity that generates a secondary
structure.
2) Secondary structure- Each single t- RNA
shows extensive internal base pairing and
acquires a clover leaf like structure. The
structure is stabilized by hydrogen bonding
between the bases and is a consistent feature.
16Biochemistry For Medics
17. Structural characteristics of t-
RNA
Secondary structure (Clover leaf structure)
All t-RNA contain 5 main arms or loops which are
as follows-
a) Acceptor arm
b) Anticodon arm
c) D HU arm
d) TΨ C arm
e) Extra arm
17Biochemistry For Medics
18. Secondary structure of t- RNA
a) Acceptor arm
The acceptor arm is at 3’ end
It has 7 base pairs
The end sequence is unpaired Cytosine,
Cytosine-Adenine at the 3’ end
The 3’ OH group terminal of Adenine binds with
carboxyl group of amino acids
The t RNA bound with amino acid is called
Amino acyl t RNA
CCA(cyt-cyt-ade) attachment is done post
transcriptionally
18Biochemistry For Medics
19. Secondary structure of t- RNA
The carboxyl group of amino acid is attached to 3’OH group of Adenine
nucleotide of the acceptor arm. The anticodon arm base pairs with the codon
present on the m- RNA
19Biochemistry For Medics
20. Secondary structure of t-
RNA(contd.)
c) DHU arm
It has 3-4 base pairs
Serves as the recognition site for the enzyme (amino
acyl t RNA synthetase) that adds the amino acid to the
acceptor arm.
d) TΨC arm
This arm is opposite to DHU arm
Since it contains pseudo uridine that is why it is so
named
It is involved in the binding of t RNA to the ribosomes
20Biochemistry For Medics
21. Secondary structure of t-
RNA(contd.)
b) Anticodon arm
Lies at the opposite end of acceptor arm
5 base pairs long
Recognizes the triplet codon present in the m
RNA
Base sequence of anticodon arm is
complementary to the base sequence of m RNA
codon.
Due to complimentarity it can bind specifically
with m RNA by hydrogen bonds.
21Biochemistry For Medics
22. Secondary structure of t-
RNA(contd.)
e) Extra arm or Variable arm
About 75 % of t RNA molecules possess
a short extra arm
If about 3-5 base pairs are present the
t-RNA is said to be belonging to class 1.
Majority t -RNA belong to class 1.
The t –RNA belonging to class 2 have
long extra arm, 13-21 base pairs in length.
22Biochemistry For Medics
23. Tertiary structure of t- RNA
The L shaped tertiary
structure is formed by
further folding of the clover
leaf due to hydrogen bonds
between T and D arms.
The base paired double
helical stems get arranged in
to two double helical
columns, continuous and
perpendicular to one
another.
23Biochemistry For Medics
24. Ribosomal RNA (rRNA)
• Ribosomal ribonucleic acid (rRNA) is
the RNA component of the ribosome, and is
essential for protein synthesis in all living
organisms.
• It constitutes the predominant material within
the ribosome, which is approximately 60% rRNA
and 40% protein by weight, or 3/5 of ribosome
mass.
• Ribosomes contain two major rRNAs and 50 or
more proteins. The ribosomal RNAs form two
subunits, the large subunit (LSU) and small
subunit (SSU). The LSU rRNA acts as a ribozyme,
catalyzing peptide bond formation
Biochemistry For Medics 24
25. Ribosomal RNA (rRNA)
The mammalian ribosome contains two major
nucleoprotein subunits—a larger one with a molecular
weight of 2.8 x 106 (60S) and a smaller subunit with a
molecular weight of 1.4 x 106 (40S).
The 60S subunit contains a 5S ribosomal RNA (rRNA), a
5.8S rRNA, and a 28S rRNA; there are also probably more
than 50 specific polypeptides.
The 40S subunit is smaller and contains a single 18S
rRNA and approximately 30 distinct polypeptide chains.
All of the ribosomal RNA molecules except the 5S rRNA
are processed from a single 45S precursor RNA molecule
in the nucleolus .
5S rRNA is independently transcribed.
25Biochemistry For Medics
27. Ribosomal RNA (rRNA)
The functions of the ribosomal RNA
molecules in the ribosomal particle are not
fully understood, but they are necessary for
ribosomal assembly and seem to play key
roles in the binding of mRNA to ribosomes
and its translation
Recent studies suggest that a rRNA
component performs the peptidyl transferase
activity and thus is an enzyme (a ribozyme).
27Biochemistry For Medics
28. Small RNA
Most of these molecules are
complexed with proteins to form
ribonucleoproteins and are distributed in
the nucleus, in the cytoplasm, or in both.
They range in size from 20 to 300
nucleotides and are present in 100,000–
1,000,000 copies per cell.
28Biochemistry For Medics
29. Small Nuclear RNAs (snRNAs)
snRNAs, a subset of the small RNAs, are
significantly involved in mRNA processing and
gene regulation
Of the several snRNAs, U1, U2, U4, U5, and
U6 are involved in intron removal and the
processing of hnRNA into mRNA
The U7 snRNA is involved in production of
the correct 3' ends of histone mRNA—which
lacks a poly(A) tail.
29Biochemistry For Medics
30. Small Nuclear RNAs (snRNAs).
Sn RNA s are involved in the process of splicing (intron removal) of primary
transcript to form mature m RNA. The Sn RNA s form complexes with proteins
to form Ribonucleoprotein particles called snRNPs
30Biochemistry For Medics
31. Micro RNAs, miRNAs, and Small
Interfering RNAs, siRNAs
These two classes of RNAs represent a
subset of small RNAs; both play important
roles in gene regulation.
miRNAs and siRNAs cause inhibition of
gene expression by decreasing specific
protein production albeit apparently via
distinct mechanisms
31Biochemistry For Medics
32. Micro RNAs (miRNAs)
miRNAs are typically 21–25 nucleotides in
length and are generated by nucleolytic
processing of the products of distinct
genes/transcription units
The small processed mature miRNAs
typically hybridize, via the formation of
imperfect RNA-RNA duplexes within the 3'-
untranslated regions of specific target
mRNAs, leading via unknown mechanisms to
translation arrest.
32Biochemistry For Medics
33. Micro RNAs (miRNAs)
microRNAs, short non-coding RNAs present in all living organisms, have
been shown to regulate the expression of at least half of all human
genes. These single-stranded RNAs exert their regulatory action by
binding messenger RNAs and preventing their translation into
proteins.
33Biochemistry For Medics
34. Small Interfering RNAs (siRNAs)
siRNAs are derived by the specific nucleolytic cleavage
of larger, double-stranded RNAs to again form small 21–
25 nucleotide-long products.
These short siRNAs usually form perfect RNA-RNA
hybrids with their distinct targets potentially anywhere
within the length of the mRNA where the complementary
sequence exists.
Formation of such RNA-RNA duplexes between siRNA
and mRNA results in reduced specific protein production
because the siRNA-mRNA complexes are degraded by
dedicated nucleolytic machinery;
some or all of this mRNA degradation occurs in specific
organelles termed P bodies.
34Biochemistry For Medics
35. Small Interfering RNAs (siRNAs)
Small interfering RNA (siRNA) are 20-25 nucleotide-long double-stranded RNA
molecules that have a variety of roles in the cell. They are involved in the RNA
interference (RNAi) pathway, where it interferes with the expression of a
specific gene by hybridizing to its corresponding RNA sequence in the
target mRNA. This then activates the degrading mRNA. Once the target
mRNA is degraded, the mRNA cannot be translated into protein. 35Biochemistry For Medics
36. Significance of mi RNAs and si
RNAs
Both miRNAs and siRNAs represent
exciting new potential targets for
therapeutic drug development in humans.
In addition, siRNAs are frequently used to
decrease or "knock-down" specific protein
levels in experimental procedures in the
laboratory, an extremely useful and
powerful alternative to gene-knockout
technology.
36Biochemistry For Medics
37. Summary
RNA exists in several different single-stranded
structures, most of which are directly or indirectly
involved in protein synthesis or its regulation.
The linear array of nucleotides in RNA consists of A, G,
C, and U, and the sugar moiety is ribose.
The major forms of RNA include messenger RNA
(mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA),
and small nuclear RNAs (snRNAs; miRNAs).
Certain RNA molecules act as catalysts (ribozymes).
miRNAs and siRNAs represent exciting new potential
targets for therapeutic drug development in humans.
37Biochemistry For Medics