DNA and RNA are the building blocks of life that work together to direct protein synthesis. DNA stores and replicates genetic information, while various types of RNA help read and translate DNA instructions. The document defines DNA and RNA, describing their structures, functions, and how they work cooperatively through processes like transcription, translation, and semi-conservative replication to create proteins. Key differences between DNA and RNA include their single vs. double-stranded nature and the presence of thymine in DNA and uracil in RNA.

1. Knowing about
DNA and RNA
Discover the fascinating world of DNA and RNA. Learn about the structures,
functions and method of replication of these building blocks of life.
by Dhruba Mahata
VCOVS /B.Optometry/UG-1

2. What are DNA and RNA
DNA (Deoxyribonucleic Acid):
• DNA is a molecule in our cells that holds important instructions for how our
bodies work, like a "recipe book" for life.
• It looks like a twisted ladder and is made up of small building blocks called
nucleotides.
• When cells divide or make new ones, DNA is copied to pass on the
instructions to the new cells.
RNA (Ribonucleic Acid):
• RNA is another molecule in our cells that helps read and use the instructions from
DNA to build proteins.
• It's like a "delivery person" that carries the DNA's instructions to the protein-making
factories in cells.
• There are different types of RNA, each with its own job, like reading the DNA,
bringing building blocks for proteins, and helping with protein construction.
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3. What are we going to learn:
Definition
Differences
Types
Functions
Structure

4. What is DNA
The Structure of DNA:
• Double-helix:
DNA has a twisted ladder-like structure, resembling a spiral staircase.
• Nucleotides:
It is composed of nucleotide building blocks, each containing a sugar-
phosphate backbone and one of four nitrogenous bases (adenine,
thymine, cytosine, guanine).
• Complementary Base Pairing:
Adenine (A) pairs with Thymine (T)
Cytosine (C) pairs with Guanine (G),
• It is a molecule that carries the genetic instructions necessary for the growth, development, functioning
and reproduction of all known living organisms and many viruses.
• DNA is often referred to as the “Genetic Code" of life.
Significance:
• Accurate replication during cell division and protein synthesis
• Influencing heredity and genetic inheritance in living organisms.

5. The Different Types of DNA
DNA is the genetic material that carries the instructions for the development and function of all living organisms.
There are several different types of DNA, including B-DNA, Z-DNA, and A-DNA (A-form Deoxyribonucleic acid)
Each type has a slightly different structure and function.

6. What is RNA
The Structure of RNA
• Single-stranded:
Unlike DNA, RNA is composed of a single strand of nucleotides.
• Nucleotides:
Similar to DNA, RNA is made up of nucleotide building blocks
containing a sugar-phosphate backbone and one of four nitrogenous
bases (Adenine, Uracil, Cytosine, Guanine).
• Complementary Base Pairing:
Adenine (A) pairs with Uracil (U), and
Cytosine (C) pairs with Guanine (G)
• It is a single-stranded nucleic acid molecule that plays a key role in
gene expression and protein synthesis in cells.
• It carries the genetic information from DNA to the ribosomes, where
proteins are assembled based on the sequence of nucleotides in the RNA.
Significance:
• RNA plays a critical role in transferring genetic information from DNA to
the ribosomes, where proteins are synthesized based on the genetic code.

7. The Different Types of RNA
RNA is a type of molecule that plays a key role in the synthesis of proteins.
The three main types of RNA are: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
Each type has a specific function in the process of protein synthesis.
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8. Difference between DNA and RNA :
• DNA is a double-stranded molecule
• DNA contains the Deoxyribose Sugar
• DNA has the nitrogenous base Thymine (T),
• Nucleotides are anti-parallel as DNA is
double-stranded
• RNA is single-stranded
• RNA contains the Ribose Sugar
• RNA has Uracil (U) instead of Thymine (T)As
RNA is single-stranded, only one strand is
visible.
Structural:
Locational:
• DNA is primarily found in the Nucleus of
Eukaryotic cells and in some organelles;
such as Mitochondria and Chloroplasts.
• RNA is found in both the Nucleus and
Cytoplasm of Cells.

9. So,
DNA and RNA are same right….?
Aren’t they !?
Yes, they aren’t the same !

10. The Functions of DNA and RNA
Genetic Information
Storage 📦
DNA serves as the
repository of an
organism's genetic
information, carrying the
instructions necessary for
growth, development, and
functioning.
DNA Replication ♻️
DNA replication is the
process by which DNA
makes a copy of itself before
cell division. The steps
involved are initiation,
elongation and termination.
Inheritance 👶
During reproduction, DNA
is passed from parents to
offspring, ensuring the
transfer of hereditary traits
from one generation to the
next.
Functions of DNA:

11. Protein Synthesis 🔬
Different types of RNA,
such as messenger RNA
(mRNA), transfer RNA
(tRNA), and ribosomal
RNA (rRNA), work together
to ensure the proper
assembly of amino acids
into proteins at the
ribosomes.
Transcription ✍
RNA is synthesized during
transcription, where it
serves as a complementary
copy of a specific gene
region in the DNA.
Gene Expression 🧬
RNA plays a crucial role in
gene expression,
transferring genetic
information from the DNA to
the ribosomes for protein
synthesis.
Regulation of Gene Expression ☑
Some types of RNA, such as microRNA (miRNA) and small
Interfering RNA (siRNA), are involved in gene regulation by
suppressing or inhibiting the translation of specific mRNA molecules.
The Functions of DNA and RNA
Functions of RNA:
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12. How DNA and RNA Work Together
While DNA and RNA have different structures and functions, they work together to create the proteins that
make up our bodies. DNA serves as the master blueprint, while RNA acts as a messenger to help translate the
instructions into protein.
Transcription:
In transcription, DNA is converted into RNA
by an enzyme called RNA polymerase.
This process occurs in the nucleus and
produces a single-stranded RNA molecule.
Translation:
In translation, the RNA molecule is converted
into protein by ribosomes.
Transfer RNA (tRNA) brings amino acids to
the ribosome, where they are linked together
to form a protein chain.
We work together

13. How DNA and RNA Work Together
Replication:
• DNA replication involves unwinding the double helix at
origins, where primase creates RNA primers.
• DNA polymerase adds nucleotides to the growing
strands, following leading and lagging pathways.
• Replication ends when forks meet, resulting in two
semi-conserved DNA molecules, each with an original
and a new strand.
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14. The Genetic Code
The genetic code is a set of rules that govern the translation of genetic information stored in DNA and
transcribed into RNA into specific amino acids during protein synthesis. The code consists of 64 codons,
each of which codes for a specific amino acid.
1
Hypotheses &
Experiments
The discovery of the genetic
code by Marshall Nirenberg
was a result of many
experiments and hypotheses,
beginning with the discovery of
DNA's structure in 1953 by
Johann Friedrich Miescher
2 Codon Triplets
The code consists of
codons, which are three-
nucleotide sequences in
mRNA. Each codon
corresponds to a specific
amino acid or serves as a
start or stop signal for
protein
3 Redundancy
Multiple codons can code for
the same amino acid, reducing
the impact of mutations and
ensuring robustness and
adaptability in the face of
genetic changes.
Marshall Nirenberg
Johann Friedrich Miescher

15. 4 Start and Stop Signals
The start codon (AUG) initiates
protein synthesis, while stop
codons (UAA, UAG, UGA) mark
the termination of translation.
5 T-RNA Molecules
The genetic code is a triplet
code, meaning that three
nucleotides code for one amino
acid. For example, GAA codes
for glutamic acid.
6 Evolutionary insights
The genetic code is non-overlapping,
which means that each codon only
codes for one amino acid and does not
overlap with the next.
The Genetic Code
7
Conserved Features
While the genetic code is considered universal, some variations exist in
certain organisms or organelles, such as mitochondria.
These differences offer clues about evolutionary relationships and
adaptations in specific environments.

16. Method of DNA Replication
DNA replication is the process by which cells make a copy of their DNA before cell division.
Replication is semi-conservative, meaning that each new strand consists of one original and
one newly synthesized strand.
1 Initiation: Replication starts at
specific origins
2
Priming: Primase synthesizes
RNA primers.
3 Elongation: DNA polymerase adds
nucleotides in the 5' to 3' direction.
4
Leading & Lagging Strands:
Leading strand synthesized
continuously, lagging strand in
fragments. 5 Proofreading:
DNA polymerase corrects errors.

17. 6 Termination:
Replication ends when forks meet.
7
Semi-Conservative: Each new DNA
molecule contains one original and one
newly synthesized strand.
7 Replication Machinery:
Proteins coordinate replication.
8
Speed & Accuracy: High replication
speed with low error rate.
Method of DNA Replication

18. References and Bibliography
Further readings and resources to learn more about DNA and RNA:
"Molecular Biology of the Cell" by Bruce Alberts,2020 Lewin's Genes XII by Jocelyn E. Krebs and Elliott S
Goldstein
"Principles of Genetics" by D. Peter Snustad and
Michael J. Simmons, 2019
"The Genetic Code: A Nature-Nurture Hybrid" by
Martin F. Yanofsky, Annual Review of
Biochemistry, 2007
"Genes IX" by Benjamin Lewin, 2017
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19. Conclusion:
In summary, the intertwined roles of DNA and RNA are the foundation of biological processes.
DNA's stability and RNA's versatility collaboratively drives the cellular functions.
Understanding their partnership portrays life's molecular interconnections and inspires
advancements in medicine, biotechnology, and our comprehension of existence itself.

20. Thank you