this presentation discusses what the central dogma is, its function, and its relevance.

1. THE CENTRAL DOGMA
GROUP 4
OF MOLECULAR
BIOLOGY

2. 01
01
02
03
05
04
CONTENTS
RNA AND PROTEINS
02
03
TRANSCRIPTION
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04
DNA REPLICATION
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MODIFICATION & TRANSLATION
DNA

3. Central Dogma of
Molecular Biology
how genetic
information is used
to make proteins
proposed by Francis
Crick 1958
happens in all living
organisms

4. How It Works & Why
It’s Important
Replication – DNA
makes a copy of itself
Transcription – DNA
is turned into a
message
(mRNA)happens in all
living organisms
Translation – The
message is used to
build proteins

5. COMPONENTS OF THE CENTRAL
DOGMA OF MOLECULAR BIOLOGY
RNA
01
02
03
DNA
PROTEINS

6. DNA

7. DNA is the molecule that carries genetic information.
Passed from parents to offspring, determining inherited traits.
Contains the instructions needed for an organism’s growth,
development, and survival.
DNA (deoxyribonucleic acid)

8. DNA is your genetic blueprint – It contains the instructions for
building and maintaining your body.
Controls cell functions – Every process in the body, from
digestion to immune response, is guided by DNA.
Ensures life continuity – DNA is passed down to offspring to
maintain genetic traits.
Why is DNA Important?

9. THE DNA MODEL
Proposed by Francis Crick & James Watson
(1953)
DNA has a double-helix shape, like a twisted
ladder.
It can spiral clockwise or counterclockwise.
The basic unit (nucleotide) consists of:
✔A phosphate group
✔A sugar (deoxyribose)
✔A nitrogenous base (A, T, C, G)

11. DEOXYRIBOSE

12. DEOXYRIBOSE
A SUGAR GROUP IN DNA
THE PREFIX DEOXY- IN "DEOXYRIBOSE" MEANS THAT RIBOSE HAS
LOST AN OXYGEN ATOM.

13. DEOXYRIBOSE
DEOXYRIBOSE IS A PENTOSE SUGAR, MEANING IT CONTAINS FIVE
CARBON ATOMS. ITS CHEMICAL FORMULA IS C₅H₁₀O₄. THE "DEOXY"
PART OF ITS NAME COMES FROM THE FACT THAT IT IS A MODIFIED
VERSION OF RIBOSE, ANOTHER SUGAR FOUND IN RNA
(RIBONUCLEIC ACID).

14. DEOXYRIBOSE
THE ABSENCE OF AN OXYGEN ATOM ON THE
SECOND CARBON IN THE DEOXYRIBOSE SUGAR
HELPS DISTINGUISH DNA FROM RNA.

15. PURINES &
PYRIMIDINES
Purines, which are adenine and
guanine, have a double-ringed
structure, and the pyrimidines,
which are cytosine, thymine, and
uracil, contain only one ring in their
structure

16. COMPLEMENTARY BASE
PAIRING
In DNA, adenine (A) is paired with
thymine (T), and guanine (G) is
paired with cytosine (C).

17. DNA MOLECULES
STRUCTURES

18. SIGNIFICANCE OF
COMPLIMENTARY BASE PAIRING
ALLOWS DNA TO REPLICATE ITSELF ACCURATELY, AND ENSURES A
PROPER TRANSCRIPTION AND TRANSLATION MAINTAINING GENETIC
INFORMATION THROUGH SPECIFIC BASE PAIRINGS, AND FORMING
THE STABLE DNA DOUBLE HELIX STRUCTURE.

20. RNA
DEFINITION
RNA (RIBONUCLEIC ACID) IS A MOLECULE
THAT HELPS CARRY OUT THE
INSTRUCTIONS STORED IN DNA.

21. RNA
DEFINITION
RNA (RIBONUCLEIC ACID) IS A MOLECULE
THAT HELPS CARRY OUT THE
INSTRUCTIONS STORED IN DNA.
SIGNIFICANCE
It helps make proteins, controls genes,
speeds up cell reactions, and is used in
medicine, making it essential for life.

22. TYPES OF RNA
01
02
03
Messenger RNA (mRNA)

23. TYPES OF RNA
Ribosomal RNA (rRNA)
01
02
03
Messenger RNA (mRNA)

24. TYPES OF RNA
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)
01
02
03
Messenger RNA (mRNA)

25. MRNA (MESSENGER RNA) IS A TYPE OF RNA
THAT CARRIES GENETIC INSTRUCTIONS
FROM DNA TO THE CELL’S PROTEIN-
MAKING MACHINERY.
Messenger RNA (mRNA)

26. Ribosomal RNA (rRNA)
FORMS PART OF RIBOSOMES, WHICH HELP
ASSEMBLE PROTEINS

27. Transfer RNA (tRNA)
BRINGS AMINO ACIDS TO THE RIBOSOME
TO BUILD PROTEINS

30. PROTEIN
Proteins are essential building
blocks of life, providing
structural support (e.g.,
collagen), transporting
molecules (e.g., hemoglobin),
acting as enzymes for
digestion, and determining
blood type. They also regulate
the movement of substances
in and out of cells.

31. PROTEIN
Gives your body a
structure
Transport Oxygen
Determine blood type
Allow substances to move
inn and out of the cells

34. THE GENETIC CODE
( NITROGEN BASES)
A (ADENINE)
U (URACIL)
G (GUANINE)
C (CYTOSINE)

35. CODON
A (ADENINE)
U (URACIL)
G (GUANINE)
C (CYTOSINE)
EACH 3 LETTER SEQUENCE IS
CALLED CODON

36. AUG- CODE FOR METHIONINE (START
CODONS)
UUU- CODES FOR PHENYLALANINE
GGC- CODE FOR GLYCINE
UAA, UAG, UGA- STOP CODONS

37. The first letter of the codon is found in the first column
(left side).
The second letter is found in the top row.
The third letter is found in the right column.
HOW TO READ THE GENETIC CODE TABLE

39. PROCESSES IN THE CENTRAL DOGMA
01
DNA REPLICATION
02
TRANSCRIPTION
03
MODIFICATION
04
TRANSLATION

41. DNA REPLICATION
DEFINITION
THE PROCESS BY WHICH A DOUBLE-
STRANDED DNA MOLECULE IS COPIED TO
PRODUCE TWO IDENTICAL DNA MOLECULE
SIGNIFICANCE
THIS IS ESSENTIAL IN CELL DIVISION (S
PHASE), ENSURING THAT EACH NEW
DAUGHTER CELL RECEIVES A COMPLETE SET
OF PARENT CELLS

42. DNA REPLICATION
DIFFERENT ENZYMES ARE IMPORTANT IN CARRYING OUT DNA
REPLICATION. ENZYMES INVOLVED IN DNA REPLICATION;
HELICASE - Unwinds the DNA double helix
DNA Polymerase - an enzyme that creates new copies of DNA
DNA Primase - an enzyme that creates short RNA primers for DNA
replication
DNA Ligase - an enzyme that joins DNA strands together by forming a
phosphodiester bond ( a chemical bond that forms the backbone of DNA
and RNA)
Topoisomerase - an enzyme that regulates the structure of DNA by
breaking and re-joining DNA strands
Exonuclease - enzyme that breaks down nucleic acids by removing
nucleotides from the end of a chain

43. RNA Primer - a short single stranded RNA molecule that starts the
process of DNA replication
Okazaki Fragment - short sigments of DNA that are created
during DNA replication.
Single-strand Binding Protein - proteins that bond single-
stranded DNA
5' To 3' Direction and 3'to 5' Direction - refers to the
orientation of the two strands of the DNA

44. Lagging Strand - a strand of
DNA that is synthesized in
small fragments during DNA
replication
requires new primer for
each okazaki fragment
Leading Strand - starts at a
replication fork where it is
synthesized continously in the 5
to 3 direction
Replication Fork - y-shaped
structure when DNA splits into
two strand for replication

45. https://images.app.goo.gl/emFBNpSiEC865oVZ7
DNA REPLICATION

46. PROCESS
ELONGATION
INITIATION
TERMINATION
01
02
03

47. In this process, an enzyme called helicase unwinds and separate the DNA into two
single strand. The origin of replication happens in Adenine and Thymine,
because only two hydrogen bonds are in between them. The structure formed
from this process is called replication fork
PROCESS: INITIATION
Next, the RNA primase binds the RNA nucleotides to the initation point of the 3
to 5 parent strand. The RNA nucleotides act as a primer, or the starting point
for DNA synthesis.

48. DNA STRUCTURE
HELICASE UNWINDING
THE DNA DOUBLE HELIX

49. Elongation is where the actual synthesis of new DNA strand takes place. When an
enzyme called DNA polymerase adds DNA nucleotides to the 3' end of the
growing strand, using the existing strand as a template, wherein only those
complementary to the template nucleotides are added to the new strand.
However, DNA polymerase can only synthesize new strands in the 5'-3' direction.
Because of the diffrent arrangement of the carbon atoms in the two strand, the
elongation process has two different process. Both version accur simultaneously.
PROCESS: ELONGATION

50. The leading strand is synthesized continuously in the 5' to 3'
direction. This is because the DNA polymerase can move along the
template strand in the same direction as the replication fork. A single
RNA primer is needed to initiate synthesis, and then the DNA
polymerase adds nucleotides complementary to the template
strand.
LEADING STRAND

51. The lagging strand presents a challenge because it runs in the
3' to 5' direction. DNA polymerase can only add nucleotides to
the 3' end, so it cannot synthesize this strand continuously.
Instead, it synthesizes short fragments called Okazaki
fragments. Each fragment requires its own RNA primer, and
the DNA polymerase synthesizes the fragment in the 5' to 3'
direction, away from the replication fork.
LAGGING STRAND

52. LEADING AND LAGGING STRAND

53. The final step in DNA replication involves filling in gaps and joining the newly
synthesized DNA strands. DNA polymerase stops when it reaches a section
that's already been replicated. On the lagging strand, the RNA primers that
were used to start replication are removed by an enzyme called exonuclease.
These gaps are then filled in by DNA polymerase, which attaches to the end of
the DNA fragment. Finally, an enzyme called ligase joins the fragments
together, creating two complete DNA molecules. This process is called
semiconservative because each new DNA molecule is made up of one original
strand and one newly synthesized strand.
PROCESS: TERMINATION

54. TERMINATION

55. DNA replication is a precise process, and errors are minimized by a built-in
"proofreading" function of DNA polymerase. As DNA polymerase builds the new
DNA strand, it checks for correct base pairing. If a wrong base is added, it
creates an unstable bond that DNA polymerase can easily detect. Once
detected, the incorrect base is immediately replaced by the polymerase,
ensuring accuracy in the newly replicated DNA.
PROOFREADING

57. Transcription is the process where RNA is
synthesized from a DNA template. It is the
first step in gene expression, allowing
genetic information to be converted into a
form that can be used to produce proteins.

58. It is the first step in the central dogma
of molecular biology
(DNA → RNA → Protein).
Transcription converts DNA into RNA.
Translation converts RNA into protein.

61. The Three Stages of Transcription

62. RNA polymerase binds to a promoter (a specific
DNA sequence that signals where transcription
should start).
The DNA strands unwind.
RNA polymerase uses one strand of DNA as a
template to start RNA synthesis.
What Happens?

64. The promoter acts like a "start button" for
transcription.
Only one DNA strand (called the template
strand) is copied.
The other strand (coding strand) is identical to
the mRNA sequence (except that RNA has U
instead of T).
Key Points:

65. RNA polymerase moves along the DNA template strand, adding
RNA nucleotides to build an mRNA molecule.
The nucleotides follow complementary base pairing rules:
A (Adenine) pairs with U (Uracil) in RNA.
T (Thymine) pairs with A.
C (Cytosine) pairs with G.
G (Guanine) pairs with C.
What Happens?

67. If the DNA template strand has this
sequence:
TAC GCG TAA
Example:

68. Then the mRNA strand will be:
AUG CGC AUU
Example:

69. The growing mRNA strand is
complementary to the DNA template
strand.
RNA polymerase moves from 3' to 5' on
the DNA template, but builds RNA from 5'
to 3'.
Key Points:

70. RNA polymerase reaches a termination sequence (a specific
DNA region that signals the end of transcription).
The RNA polymerase detaches from the DNA, and the newly
synthesized mRNA is released.
The DNA recoils into its double-helix shape.
What Happens?

72. Termination stops transcription.
mRNA is released and ready for
processing (in eukaryotes) or
translation (in prokaryotes).
Key Points:

74. mRNA Modification
Modification occurs after
transcription, and before
translation.
It plays an important role in
making sure that the mRNA is
fully matured and ready for
translation

75. PROCESSES DURING MODIFICATION
RNA SPLICING
5' END CAPPING
POLY-A TAIL
1
2
3

77. Introns are removed from primary transcripts by cleavage at
conserved sequences called splice sites. These sites are found
at the 5′ and 3′ ends of introns.
RNA SPLICING
Splicing occurs during protein synthesis, and involves cutting
out and rearranging sections of mRNA.

78. WHAT HAPPENS DURING SPLICING?
Large pieces known as introns (intervening sequences) are cut out while they
are still in the nucleus
The remaining portions called the exons (expressed sequences) are then
spliced with the help of spliceosomes back together to form the final mRNA.

79. RNA SPLICING

80. RNA SPLICING
mRNA Splicing is an important step in the transcription
process, as without removing the introns the correct protein
cannot be formed.
mRNA Splicing is also part of the regulation of gene
expression and protein levels in the cell.

82. 5' END CAPPING
Another way of modifying the produced mRNA into its functional form.
This process protects the mRNA from exonuclease activity that might degrade
the mRNA. It also regulates nuclear transport and promotes the translation and
the excision of the introns.

83. WHAT HAPPENS DURING 5'
END CAPPING?
Basically means adding a protective “cap” in order to protect the mRNA.

85. POLY-A TAIL
A shortcut for polyadenylation. Allows the addition of multiple adenosine
monophosphates at the end of the mRNA molecule.
The poly-A tail is a long chain of adenine nucleotides that is added to a
messenger RNA (mRNA) molecule during RNA processing to increase the
stability of the molecule.

86. WHAT HAPPENS DURING
POLY-A TAIL?
The addition of adenine bases at the end of mRNA also protects it from
enzymatic degradation in the cytoplasm and aids in the termination process.

87. 5' capping is when a modified
guanine nucleotide is added to the 5'
end of the nascent mRNA, forming a
protective cap structure. This cap
protects the mRNA from degradation,
and plays a key role in initiating
translation by helping the ribosome
recognize and bind to the mRNA.
The Poly-A tail process involves the
addition of a chain of adenine
nucleotides to the 3' end of eukaryotic
mRNA after transcription.
RNA splicing is a critical process in eukaryotic
cells that removes non-coding regions, called
introns, from the pre-mRNA and joins the
remaining coding regions, called exons,
together.

89. Occurs in the ribosome (cytoplasm or rough ER)
mRNA is read in codons (triplets of bases)
tRNA carries amino acids to the ribosome
Three stages: Initiation, Elongation, Termination
Result: A polypeptide (protein) is formed
TRANSLATION

92. Resource page