DNA
its Discovery
Who Discovered DNA?
Credit for who first identified DNA is often mistakenly given to James Watson and Francis Crick, who just furthered Miescher’s discovery with their own groundbreaking research nearly 100 years later. Watson and Crick contributed largely to our understanding of DNA in terms of genetic inheritance, but much like Miescher, long before their work, others also made great advancements in and contributions to the field.
In 1866, before many significant discoveries and findings, Gregor Mendel was the first to suggest that characteristics are passed down from generation to generation. Mendel coined the terms as recessive and dominant.
In 1869, Friedrich Miescher identified the “nuclein” by isolating a molecule from a cell nucleus that would later become known as DNA.
In 1881, Nobel Prize winner and German biochemist Albrecht Kossel, who is credited with naming DNA, identified nuclein as a nucleic acid. He also isolated those five nitrogen bases that are now considered to be the basic building blocks of DNA and RNA: adenine (A), cytosine (C), guanine (G), thymine (T) and uracil (U) in case of RNA).
In 1882, Walther Fleming devoted research and time to cytology, which is the study of chromosomes. He discovered mitosis in 1882 when he was the first biologist to execute a wholly systematic study of the division of chromosomes. His observations that chromosomes double is significant to the later discovered theory of inheritance.
In Early 1900s, Theodor Boveri and Walter Sutton were independently working on what’s now known as the Boveri-Sutton chromosome theory, or the chromosomal theory of inheritance. Their findings are fundamental in our understanding of how chromosomes carry genetic material and pass it down from one generation to the next.
In 1902, Mendel’s theories were finally associated with a human disease by Sir Archibald Edward Garrod, who published the first findings from a study on recessive inheritance in human beings in 1902. Garrod opened the door for our understanding of genetic disorders resulting from errors in chemical pathways in the body.
In 1944, Oswald Avery first outlined DNA as the transforming principle, which essentially means that DNA transform cell properties.
it gives information about the nucleus which is the major cell component and its various parts like nuclear pores,nucleolus etc. it helps in the replication of DNA which contain genetic material.
STRUCTURE AND FUNCTIONS OF NUCLEUS OF A CELL.pptxRASHMI M G
The nucleus is the part of a cell that contains DNA organized into chromosomes and is located in the middle of the cell. It is surrounded by the nuclear envelope, which is a double membrane that separates the nucleus from the cytoplasm. The nuclear envelope contains nuclear pores, which are gateways that allow molecules to move into and out of the nucleus.
The Cell: The Histology Guide
Nucleus - The Cell: The Histology Guide - University of Leeds
The nucleus is found in the middle of the cells, and it contains DNA arranged in chromosomes. It is surrounded by the nuclear envelope, a double nuclear membrane (outer and inner), which separates the nucleus from the cytoplasm. The outer membrane is continuous with the rough endoplasmic reticulum.
open.baypath.edu
Nucleus – BIO109 Biology I Introduction to Biology
The boundary of the nucleus, called the nuclear envelope, is a double membrane that contains small openings called nuclear pores. These pores are gateways that allow molecules to move into and out of the nucleus, enabling it to communicate with the rest of the cell.
The nucleus has three main parts:
Nuclear membrane: A protective barrier of the nucleus
Nucleoplasm: The cytoplasm of the nucleus, which is a semifluid matrix that contains chromatin, the less condensed form of DNA that organizes into chromosomes during mitosis or cell division
Nucleolus: A spherical structure that produces and assembles the cell's ribosomes
The nucleus controls and regulates the activities of the cell, such as growth and metabolism.
What are the 4 types of nucleus?
What are the 3 parts of a nucleus?
How many nuclei are in a cell?
Ask a follow up
it gives information about the nucleus which is the major cell component and its various parts like nuclear pores,nucleolus etc. it helps in the replication of DNA which contain genetic material.
STRUCTURE AND FUNCTIONS OF NUCLEUS OF A CELL.pptxRASHMI M G
The nucleus is the part of a cell that contains DNA organized into chromosomes and is located in the middle of the cell. It is surrounded by the nuclear envelope, which is a double membrane that separates the nucleus from the cytoplasm. The nuclear envelope contains nuclear pores, which are gateways that allow molecules to move into and out of the nucleus.
The Cell: The Histology Guide
Nucleus - The Cell: The Histology Guide - University of Leeds
The nucleus is found in the middle of the cells, and it contains DNA arranged in chromosomes. It is surrounded by the nuclear envelope, a double nuclear membrane (outer and inner), which separates the nucleus from the cytoplasm. The outer membrane is continuous with the rough endoplasmic reticulum.
open.baypath.edu
Nucleus – BIO109 Biology I Introduction to Biology
The boundary of the nucleus, called the nuclear envelope, is a double membrane that contains small openings called nuclear pores. These pores are gateways that allow molecules to move into and out of the nucleus, enabling it to communicate with the rest of the cell.
The nucleus has three main parts:
Nuclear membrane: A protective barrier of the nucleus
Nucleoplasm: The cytoplasm of the nucleus, which is a semifluid matrix that contains chromatin, the less condensed form of DNA that organizes into chromosomes during mitosis or cell division
Nucleolus: A spherical structure that produces and assembles the cell's ribosomes
The nucleus controls and regulates the activities of the cell, such as growth and metabolism.
What are the 4 types of nucleus?
What are the 3 parts of a nucleus?
How many nuclei are in a cell?
Ask a follow up
Discovery of nucleus
Evolution of nucleus
Structure of nucleus
Function of nucleus
Diseases related with nucleus
The nucleus was the first organelle to be discovered.
The probably oldest preserved drawing dates back to the early microscopist Antonie van Leeuwenhoek (1632 – 1723). He observed a "Lumen", the nucleus, in the red blood cells of salmon.
The nucleus was also described in 1831 by Scottish botanist Robert Brown.
Brown was studying orchids under microscope when he observed an opaque area, which he called the areola or nucleus, in the cells of the flower's outer layer. He did not suggest a potential function.
The cell nucleus is a membrane bound structure that:-
Contains the cell's hereditary information
Controls the cell's growth and reproduction
Direct the other components of cell through protein regulation
Make Proteins through central dogma of cell
DNA mRNA Protein
Emery-Dreifuss muscular dystrophy
Mutations in nuclear lamins associated with Emery-Dreifuss muscular dystrophy.
Emery-Dreifuss muscular dystrophy (EDMD) is a neuromuscular degenerative condition with an associated dilated cardiomyopathy and cardiac conduction defect.
It can be inherited in either an X-linked or autosomal manner by mutations in the nuclear proteins emerin and lamin A/C, respectively.
Traditionally muscular dystrophies were associated with defects in sarcolemma-associated proteins and, therefore, a nuclear connection suggested the existence of novel signalling pathways associated with this group of diseases.
Subsequently, other mutations in the lamin A/C gene were attributed to a range of tissue-specific degenerative conditions, collectively known as the 'laminopathies’.
Nucleus-the heart of the cell-cellular organellesbiOlOgyBINGE
In cell biology, the nucleus is a membrane-bound organelle found in eukaryotic cells.
The nucleus is found in all the eukaryotic cells of the plants and animals.
here u will find every detail of nucleus.
for more details ,visit @biOlOgy BINGE-insight learning (youtube channel)
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Discovery of nucleus
Evolution of nucleus
Structure of nucleus
Function of nucleus
Diseases related with nucleus
The nucleus was the first organelle to be discovered.
The probably oldest preserved drawing dates back to the early microscopist Antonie van Leeuwenhoek (1632 – 1723). He observed a "Lumen", the nucleus, in the red blood cells of salmon.
The nucleus was also described in 1831 by Scottish botanist Robert Brown.
Brown was studying orchids under microscope when he observed an opaque area, which he called the areola or nucleus, in the cells of the flower's outer layer. He did not suggest a potential function.
The cell nucleus is a membrane bound structure that:-
Contains the cell's hereditary information
Controls the cell's growth and reproduction
Direct the other components of cell through protein regulation
Make Proteins through central dogma of cell
DNA mRNA Protein
Emery-Dreifuss muscular dystrophy
Mutations in nuclear lamins associated with Emery-Dreifuss muscular dystrophy.
Emery-Dreifuss muscular dystrophy (EDMD) is a neuromuscular degenerative condition with an associated dilated cardiomyopathy and cardiac conduction defect.
It can be inherited in either an X-linked or autosomal manner by mutations in the nuclear proteins emerin and lamin A/C, respectively.
Traditionally muscular dystrophies were associated with defects in sarcolemma-associated proteins and, therefore, a nuclear connection suggested the existence of novel signalling pathways associated with this group of diseases.
Subsequently, other mutations in the lamin A/C gene were attributed to a range of tissue-specific degenerative conditions, collectively known as the 'laminopathies’.
Nucleus-the heart of the cell-cellular organellesbiOlOgyBINGE
In cell biology, the nucleus is a membrane-bound organelle found in eukaryotic cells.
The nucleus is found in all the eukaryotic cells of the plants and animals.
here u will find every detail of nucleus.
for more details ,visit @biOlOgy BINGE-insight learning (youtube channel)
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
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.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
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.
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
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
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.
1. 1
SUBMITTED TO: Dr. SARDAR AZHAR MAHMOOD
SUBMITTED BY: GURMEET SINGH
ASSIGNMENT TOPIC NUCLEUS, DNA AND CENTRAL
DOGMA OF MOLECULAR BIOLOGY
ROLL NUMBER: 2032-211003
STUDY LEVEL: MPHIL
DEPARTMENT: DEPARTMENT OF ZOOLOGY
DATE OF SUBMISSION: 10-01-2022
2. 2
Nucleus
In cell biology, the nucleus (pl. nuclei; from Latin nucleus or nuculeus, meaning
kernel or seed) is a membrane-bound organelle found in eukaryotic cells. Eukaryotes
usually have a single nucleus, but a few cell types, such as mammalian red blood
cells, have no nuclei, and a few others including osteoclasts have many. The main
structures making up the nucleus are the nuclear envelope, a double membrane that
encloses the entire organelle and isolates its contents from the cellular cytoplasm;
and the nuclear matrix (which includes the nuclear lamina), a network within the
nucleus that adds mechanical support, much like the cytoskeleton supports the cell.
The cell nucleus contains all the cell's genome, except for the small amount of
mitochondrial DNA and, in plant cells, plastid DNA. Nuclear DNA is organized as
multiple long linear molecules in a complex with a large variety of proteins, such as
histones, to form chromosomes. The genes within these chromosomes are structured
in such a way to promote cell function. The nucleus maintains the integrity of genes
and controls the activities of the cell by regulating gene expression—the nucleus is,
therefore, the control center of the cell.
Nuclear envelope and pores
A cross section of a nuclear pore on the surface of the nuclear envelope (1) the outer
ring, (2) spokes, (3) basket, and (4) filaments.
The nuclear envelope consists of two membranes, an inner and an outer nuclear
membrane. Together, these membranes serve to separate the cell's genetic material
from the rest of the cell contents and allow the nucleus to maintain an environment
distinct from the rest of the cell. Despite their close apposition around much of the
nucleus, the two membranes differ substantially in shape and contents. The inner
membrane surrounds the nuclear content, providing its defining edge Embedded
within the inner membrane, various proteins bind the intermediate filaments that
give the nucleus its structure. The outer membrane encloses the inner membrane and
is continuous with the adjacent endoplasmic reticulum membraneAs part of the
endoplasmic reticulum membrane, the outer nuclear membrane is studded with
ribosomes that are actively translating proteins across membrane. The space between
the two membranes, called the "perinuclear space", is continuous with the
endoplasmic reticulum lumen
Nuclear pore
Nuclear pores, which provide aqueous channels through the envelope, are
composed of multiple proteins, collectively referred to as nucleoporins. The pores
are about 60–80 million Daltons in molecular weight and consist of around 50 (in
3. 3
yeast) to several hundred proteins (in vertebrates). The pores are 100 nm in total
diameter; however, the gap through which molecules freely diffuse is only about 9
nm wide, due to the presence of regulatory systems within the center of the pore.
This size selectively allows the passage of small water-soluble molecules while
preventing larger molecules, such as nucleic acids and larger proteins, from
inappropriately entering or exiting the nucleus. These large molecules must be
actively transported into the nucleus instead.
Structure of Nucleus
Function of Nucleus
The nucleus provides a site for genetic transcription that is segregated from the
location of translation in the cytoplasm, allowing levels of gene regulation that are
not available to prokaryotes. The main function of the cell nucleus is to control gene
expression and mediate the replication of DNA during the cell cycle.
Cell compartmentalization
The nuclear envelope allows the nucleus to control its contents and separate them
from the rest of the cytoplasm where necessary. This is important for controlling
processes on either side of the nuclear membrane. In most cases where a cytoplasmic
process needs to be restricted, a key participant is removed to the nucleus, where it
4. 4
interacts with transcription factors to downregulate the production of certain
enzymes in the pathway. This regulatory mechanism occurs in the case of glycolysis,
a cellular pathway for breaking down glucose to produce energy.
Replication
The main function of the cell nucleus is to control gene expression and mediate the
replication of DNA during the cell cycle. It has been found that replication happens
in a localized way in the cell nucleus.
Gene expression
A generic transcription factory during transcription, highlighting the possibility of
transcribing more than one gene at a time. The diagram includes 8 RNA polymerases
however the number can vary depending on cell type. The image also includes
transcription factors and a porous, protein core.
Gene expression first involves transcription, in which DNA is used as a template to
produce RNA. In the case of genes encoding proteins, that RNA produced from this
process is messenger RNA (mRNA), which then needs to be translated by ribosomes
to form a protein. As ribosomes are located outside the nucleus, mRNA produced
needs to be exported.
Since the nucleus is the site of transcription, it also contains a variety of proteins that
either directly mediate transcription or are involved in regulating the process. These
proteins include helicases, which unwind the double-stranded DNA molecule to
facilitate access to it, RNA polymerases, which bind to the DNA promoter to
synthesize the growing RNA molecule, topoisomerases, which change the amount
of supercoiling in DNA, helping it wind and unwind, as well as a large variety of
transcription factors that regulate expression
RNA Polymerase
RNA Polymerase I is a workhorse, producing nearly fifty percent of the RNA
transcribed in the cell. It exclusively polymerizes ribosomal RNA, which forms a
large component of ribosomes, the molecular machines that synthesize proteins.
RNA Polymerase II is extensively studied because it is involved in the transcription
of mRNA precursors. It also catalyzes the formation of small nuclear RNAs and
micro RNAs.
RNA Polymerase III transcribes transfer RNA, some ribosomal RNA and a few other
small RNAs and is important since many of its targets are necessary for normal
functioning of the cell. RNA polymerases IV and V are found exclusively in plants,
5. 5
and together are crucial for the formation of small interfering RNA and
heterochromatin in the nucleus.
DNA DISCOVERY
Many people believe that American biologist James Watson and English physicist
Francis Crick discovered DNA in the 1950s. That is not the case, but DNA was first
identified in the late 1860s by Swiss chemist Friedrich Miescher. 1869 was the year
in which Swiss physiological chemist Friedrich Miescher first identified DNA what
he called as "Nuclein" inside the nuclei of human white blood cells. The term nuclein
was later changed to "nucleic acid" and eventually to deoxyribonucleic acid or DNA.
In the early 1950s, American biologist James Watson and British physicist Francis
Crick came up with their famous model of the DNA double helix. They were the
first to cross the finish line in this scientific race with others such as Linus Pauling
(who discovered protein secondary structure) also trying to find the correct model.
Franklin was an expert in a powerful technique for determining the structure of
molecules, known as X-ray crystallography. When the crystallized form of a
molecule such as DNA is exposed to X-rays, some of the rays are deflected by the
atoms in the crystal, forming a diffraction pattern that gives clues about the
molecule's structure.
Who Discovered DNA?
Credit for who first identified DNA is often mistakenly given to James Watson and
Francis Crick, who just furthered Miescher’s discovery with their own
groundbreaking research nearly 100 years later. Watson and Crick contributed
largely to our understanding of DNA in terms of genetic inheritance, but much like
Miescher, long before their work, others also made great advancements in and
contributions to the field.
6. 6
In 1866, before many significant discoveries and findings, Gregor Mendel was the
first to suggest that characteristics are passed down from generation to generation.
Mendel coined the terms as recessive and dominant.
In 1869, Friedrich Miescher identified the “nuclein” by isolating a molecule from a
cell nucleus that would later become known as DNA.
In 1881, Nobel Prize winner and German biochemist Albrecht Kossel, who is
credited with naming DNA, identified nuclein as a nucleic acid. He also isolated
those five nitrogen bases that are now considered to be the basic building blocks of
DNA and RNA: adenine (A), cytosine (C), guanine (G), thymine (T) and uracil (U)
in case of RNA).
In 1882, Walther Fleming devoted research and time to cytology, which is the study
of chromosomes. He discovered mitosis in 1882 when he was the first biologist to
execute a wholly systematic study of the division of chromosomes. His observations
that chromosomes double is significant to the later discovered theory of inheritance.
In Early 1900s, Theodor Boveri and Walter Sutton were independently working on
what’s now known as the Boveri-Sutton chromosome theory, or the chromosomal
theory of inheritance. Their findings are fundamental in our understanding of how
chromosomes carry genetic material and pass it down from one generation to the
next.
In 1902, Mendel’s theories were finally associated with a human disease by Sir
Archibald Edward Garrod, who published the first findings from a study on recessive
inheritance in human beings in 1902. Garrod opened the door for our understanding
of genetic disorders resulting from errors in chemical pathways in the body.
In 1944, Oswald Avery first outlined DNA as the transforming principle, which
essentially means that DNA transform cell properties.
7. 7
In 1944-1950, Erwin Chargaff discovered that DNA is responsible for heredity and
that it varies between species. His discoveries, known as Chargaff’s Rules, proved
that guanine and cytosine units as well as adenine and thymine units were the same
in double-stranded DNA, and he also discovered that DNA varies among species.
In Late 1940s, Barbara McClintock discovered the mobility of genes, and her
discovery is known as “jumping gene,” or the idea that genes can move on a
chromosome.
In 1951, Roslind Franklin’s work in X-ray crystallography began when she started
taking X-ray diffraction photographs of DNA. Her images showed the helical form,
which was confirmed by Watson and Crick nearly two years later.
In 1953, Watson and Crick published on DNA’s double helix structure that twists to
form the ladder like structure which they called as DNA.
When Was DNA Discovered?
What we know about DNA today can be largely credited to James Watson and
Francis Crick, who discovered the structure of DNA in 1953. This is the year they
discovered DNA’s double helix, or spiraling, intertwined structure which is
fundamental to our current understanding of DNA.
DNA CONCEPT
DNA has a regular structure. It's orientation, width, width between nucleotides,
length, and number of nucleotides per helical turn is constant. All these features were
described by Watson and Crick. Adenine is always opposite thymine, and cytosine
is always opposite guanine. The two strands are held together by hydrogen bonds.
There are two bonds between adenine and thymine and three bonds between guanine
and cytosine.
8. 8
DNA is a string of deoxyribonucleotides. These consist of three different
components. These are the deoxyribose sugar, a phosphate group, and a nitrogen
base. These nitrogen bases are further broken down into four types, including
Adenine (A)
Cytosine (C)
Guanine (G)
Thymine (T)
What is DNA Made of?
DNA is made up of molecules known as nucleotides. Each nucleotide contains a
sugar and phosphate group as well as nitrogen bases.
1. Deoxyribose sugar
This is the basic building block which is distinguished because it contains a
hydrogen (H) atom at the number 2' carbon.
2. Triphosphate group
It attached to the 5' carbon. This group is important because in a DNA chain
it undergoes a reaction with the 3' OH group to produce polydeoxynucleotide.
3. Nitrogen base
This is final component of DNA which is attached to the 1' carbon. There are
mainly Four bases are possible in DNA i.e. Two pyrimidines which are
thymine and cytosine while two purines which are adenine and guanine.
9. 9
The double stranded DNA molecule is held together by hydrogen bonds. Pairing
involves specific atoms in each base. Adenine pairs with the thymine, and guanine
pairs with cytosine. Each strand of the double-stranded DNA molecule has the same
basic structure. It is a series of series of deoxyribonucleotides linked together by
phosphodiester bonds. This bond joins a phosphate group to the 3' carbon of the
deoxyribose sugar. Each strand is complementary to the opposite strand. If one
strand has an adenine at a position, its anti-parallel strand would have a thymine at
the corresponding position. Likewise, guanine and cytosine would be
complementary according to Chargaff’s rule.
10. 10
a. Structure of DNA
CENTRAL DOGMA
The process of converting DNA into RNA and then RNA in a specific
Polypeptide, this whole process is known as central dogma.
Transcription
DNA RNA POLYPEPTIDE
Transcription Translation
CENTRAL DOGMA
11. 11
Transcription is the process of making an RNA copy of a gene sequence. It takes
place in cell nucleus.
✓ This copy is called a messenger RNA (mRNA) molecule, leaves the cell
nucleus, and enters the cytoplasm.
✓ It directs the synthesis of the protein in cytoplasm which it encodes.
Translation
The process of translating the sequence of a messenger RNA (mRNA) molecule to
a sequence of amino acids during protein synthesis. It takes place in the cytoplasm
of the cell.
➢ Genetic code describes the relationship between the sequence of base pairs in
a gene and the corresponding amino acid sequence that it encodes.
➢ In the cell cytoplasm, the ribosome reads the sequence of the mRNA in groups
of three bases to assemble the protein.
12. 12
References
1. Pauling, L., and Corey, R. B., Nature, 171, 346 (1953); Proc. U.S. Nat.
Acad. Sci., 39, 84 (1953).
2. Chargaff, E., for references see Zamenhof, S., Brawerman, G., and Chargaff,
E., Biochim. et Biophys. Acta, 9, 402 (1952).
3. Astbury, W. T., Symp. Soc. Exp. Boil. 1, Nucleic Acid, 66 (Camb. Univ.
Press, 1947).
4. Wyatt, G. R., J. Gen. Physiol., 36, 201 (1952).