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Life at molecular, cellular and tissue level:
DNA- The Code of Life

History and Structure
of Nucleic Acids
...
It has the ability to store information that controls cellular
activity and growth of an entire organism
...
Watson and Crick built
models of DNA structures in their labs and suggesting the now accepted first accurate
model of DNA
...

In 1961, Francis Crick and Sydney Brenner showed that a triplet code (codon) is used to
read genetic material in DNA
...

The demonstration by Crick and Brenner highlighted the concept of form following function
in DNA: DNA can replicate itself and also contain genetic instructions
...

Rosalind passed away before any awards could be received
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History and Structure
of Nucleic Acids
...

Shape of DNA: almost like a long-twisted ladder(spiral) made up of two strands that form a
3-D helix
...


Units that make up DNA
Phosphate

DNA is made up of Nucleotides
...

P
P
Phosphate
molecule

D
Deoxyribose
(Sugar)

C

C
Nitrogenous
(Cytosine
Base)

This is specifically a cytosine nucleotide
...

Classification of base pairs:
The two sets are called Purines and pyrimidines
...
The
only difference in organisms is the sequence of the nucleotides and how they
are strung together
...


The role of DNA:
Carries hereditary information
...

genetic information can be replicated and passed on to the next
generation
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The rest is non-coding DNA
...

Shape & Structure of RNA: RNA is in the shape of a single strand
...

The sugar in RNA is ribose and it has one more sugar than deoxyribose
...

Each Nucleotides consists of:
ribose (sugar molecule) (S)
Phosphate molecule(P)
Nitrogenous base which may be:
adenine(A)
Uracil(U)
guanine(G)
cytosine(C)

Role of RNA
Although RNA molecules have a variety of functions inside the cell, they are primarily
engaged in the process of protein synthesis
...


MITOCHONDRIAL DNA(mtDNA)

mtDNA is DNA found in the Mitochondria
...
Given that the mtDNA of the children has
genes from their mother, grandmother, and great-grandmother, this suggests
relatedness
...
It can also reveal relatedness in families and
detect if siblings share the same mother
...

Summary of process:
Helicase is an enzyme that unwinds the double helix, breaking weak hydrogen bonds
between base pairs
...
This process creates two complementary
DNA strands, which are then used as templates by DNA polymerase to rewind the strands
...
Rewinding the base pair, DNA polymerase is responsible for re-zipping the
strands, resulting in two identical DNA forms
...
We
wouldn't survive without them since our cells couldn't function properly
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The two main processes of protein synthesis are
translation, which creates the protein, and transcription, which creates mRNA
...

transfer RNA (tRNA) - carries amino acids to the mRNA
...


Process of Protein synthesis
The method of converting DNA into proteins in a single cell results in the production of
millions of proteins, essential components of biological systems
...

Transcription is the process by which DNA creates and codes for mRNA
...
The
template, a DNA strand carrying code, is formed when nucleotides are joined to a sugarphosphate backbone, creating a fresh mRNA strand
...

After that, the DNA winds up again (re-zips)
...
After the copying, the mRNA is
sent to a compartment of the cell called a ribosome, which does the next step, translation
...

start codon: The codon AUG is called the start codon as it the first codon in the transcribed
mRNA that undergoes translation
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Translation

Protein Synthesis

DNA and mRNA are generated in the nucleus through a process known as transcription,
where the coded message is transferred to a new mRNA molecule which is the
transported to the ribosomes
...

The complementary nucleotides of the codon on the mRNA are connected to the
anticodon bases in the tRNA
...
A corresponding amino acid is present on the tRNA
...

After that, a new tRNA will arrive and introduce a new amino acid when the codon next in
line is translated
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Enzymes accelerate the formation of polypeptide chains by forming bonds between amino
acids and peptides
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As "stop signals," the three codons indicate the conclusion of the message and the
completion of the protein chain
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Genetic abnormalities
Genetic anomalies are caused by mutations
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Genetic anomalies are caused by mutations
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Factors that cause changes in nucleotide sequence during a lifetime include:
nucleotides are damaged or lost:
In meiosis, paternal and maternal chromosomes cross over
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substances that cause mutations
Viruses and microorganisms

Gene mutations
Gene mutations are tiny, localized changes to the DNA strands' structure
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substitution: which is when one nucleotide is swapped for another
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DNA Profiling
Use of DNA technology
DNA profiling is a big part of technology
...
Scientists create a DNA profile of an individual using samples such as hair,
bones and other tissues by repeating these variable sequences
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Polymerase Chain Reaction (PCR) is used to synthesize large DNA fragments
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DNA fragments are
sorted and identified using techniques like electrophoresis, determining the length of a DNA
fragment
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Uses of DNA Profiling
Forensics
Diagnosing genetically inherited disorders
Identifying casualties
Paternity tests
fight illegal trade

Disadvantages
Manipulation
Accuracy issues
Violation of privacy



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