The document discusses the structure and organization of DNA and chromosomes in prokaryotes and eukaryotes. It explains that in prokaryotes, DNA is located in the cytoplasm and not enclosed in a nucleus, while in eukaryotes DNA is packaged into chromosomes within the nucleus. The basic unit of chromatin in eukaryotes is the nucleosome, which involves DNA wound around an octamer of core histone proteins (H2A, H2B, H3, H4). This facilitates a high level of DNA compaction through hierarchical levels of organization involving histone modifications and DNA-binding proteins.
Chromatin is the complex combination of DNA and proteins that makes up chromosomes. It can be made visible by staining with specific techniques and stain (thus the name chromatin which literally means colored material). The major proteins involved in chromatin are histone proteins; although many other chromosomal proteins have prominent roles too. The functions of chromatin is to package DNA into smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis and to serve as a mechanism to control gene expression and DNA replication.
Chromatin is the complex combination of DNA and proteins that makes up chromosomes. It can be made visible by staining with specific techniques and stain (thus the name chromatin which literally means colored material). The major proteins involved in chromatin are histone proteins; although many other chromosomal proteins have prominent roles too. The functions of chromatin is to package DNA into smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis and to serve as a mechanism to control gene expression and DNA replication.
Facts about DNA
Eukaryotic chromosomes
Chemical composition of eukaryotic chromosomes
Histones
Non-histone chromosomal protein
Scaffold proteins
Folded fibre model
Nucleosome model
H1 proteins
Histone modification
Chromatosome
Higher order of chromatin structure
Mechanism of DNA packaging
Conclusion
A detail ppt about Genome organization with focus on all levels of organization. Most recent research and findings about CT is also added in this ppt. Detail account of 30nm fiber and its ultra structure and types is also included.
Prokaryotic cells do not contain nuclei or other membrane-bound organelles.
The nucleoid is the area of a prokaryotic cell in which the chromosomal DNA is located.
Chromosome is several orders of magnitude larger than the cell itself.
So, if bacterial chromosomes are so huge, how can they fit comfortably inside a cell—much less in one small corner of the cell?
Most prokaryotes do not have histones (except some species of Archaea).
Thus, one way prokaryotes compress their DNA into smaller spaces is through supercoiling.
Most bacterial genomes are negatively supercoiled during normal growth.
Multiple proteins act together to fold and condense prokaryotic DNA.
One most abundant protein HU, found in the nucleoid, works with topoisomerase I to bind DNA and introduce sharp bends in the chromosome, Generating the tension necessary for negative supercoiling.
Recent studies… other proteins like integration host factor (IHF), can bind to specific sequences within the genome and introduce additional bends.
The folded DNA is then organized into a variety of conformations that are supercoiled and wound around tetramers of the HU protein, much like eukaryotic chromosomes are wrapped around histones.
Cytogenetics_ Chromosmes_Dr Jagadisha T V_PPT.pptxJagadishaTV
●To study the structure of chromosomes.
● To understand the concepts of linkage and crossing over.
● To understand structural and numerical chromosomal aberrations.
DNA, chromosomes and genomes Notes based on molecular biology of the cell. Biology Elite: biologyelite.weebly.com, please use together with the presentation
Organization of genetic materials in eukaryotes and prokaryotesBHUMI GAMETI
What is Genome ?
Types of Genome
Packaging of DNA into chromosome
GENOME ORGANIZATION IN PROKARYOTES
Plasmids
Plasmids
Nucleoid
Enzyme
GENOME ORGANIZATION IN EUKARYOTES
Chemical composition of chromatin
Nucleosome model.
Levels of DNA Packaging
Prokaryotic Genome v/s Eukaryotic Genome
Peptide vaccine containing only epitopes capable of inducing positive, desirable T cell and B cell mediated immune response.
Peptides‖ used in these vaccines are 20–30 amino acid sequences that are synthesized to form an immunogenic peptide molecule representing the specific epitope of an antigen.
sufficient for activation of the appropriate cellular and humoral responses
Eliminating allergenic and/or reactogenic responses.
The different types of external stresses that influence the plant growth and development.
These stresses are grouped based on their characters
Biotic
Abiotic
Almost all the stresses, either directly or indirectly, lead to the production of reactive oxygen species (ROS) that create oxidative stress in plants.
This damages the cellular constituents of plants which are associated with a reduction in plant yield.
Bioreactors are devices in which biological or biochemical processes develop under a closely monitored and tightly controlled environment. Bioreactors have been used in animal cell culture since the 1980s in order to produce vaccines and other drugs and to culture large cell populations. Bioreactors for use in tissue engineering have progressed from such devices.
A tissue engineering bioreactor can be defined as a device that uses mechanical means to influence biological processes. In tissue engineering, this generally means that bioreactors are used to stimulate cells and encourage them to produce extracellular matrix (ECM). There are numerous types of bioreactor which can be classified by the means they use to stimulate cells.
Microgravity is the condition in which people or objects appear to be weightless (In space). Astronauts and cosmonauts returning from long-term space missions exhibited various health problems, among them changes of the immune system, bone loss, muscle atrophy, ocular problems, and cardiovascular changes. Space biologists investigated various cell types in space to find the molecular mechanisms responsible for the observed immune disorders. Experimental cell research studying three-dimensional (3D) tissues in space and on Earth using new techniques to simulate microgravity is currently a hot topic in Gravitational Biology and Biomedicine.
An idea was considered as to producing an entire organ in vivo by bypassing many of the steps like cell isolation and expansion, culturing in bioreactors, scaffolds and growth factor delivery ect. involved in traditional tissue engineering. This concept was called the in vivo bioreactor (IVB).
Biomaterials were defined as “any substance, other than a drug, or a combination of substances, synthetic or natural in origin, which can be used for any period of time, as a whole or as a part of a system, which treats, augments or replaces any tissue, organ or function of the body”
Hematopoiesis is the process through which the body manufactures blood cells. It begins early in the development of an embryo, well before birth, and continues for the life of an individual. Hematopoiesis begins during the first weeks of embryonic development. All blood cells and plasma develop from a stem cell that can develop into any other cell.
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
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.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
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.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
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.
1.4 modern child centered education - mahatma gandhi-2.pptx
Prokaryotic chromosome structure and organization
1.
2. Inheriting Traits
• We inherit many of our physical characteristics or traits from our
parents.
• This is known as heredity – the passing of traits from one generation to
the next.
• In scientific terminology, a trait is a particular characteristic or feature
of an organism.
3. Why are traits inherited?
• Chromosomes contain the hereditary (genetic) information in living cells.
• All living cells and viruses contain genetic information in chromosomes.
• Each unique sequence of DNA (gene) carries a particular instruction for a
cell.
• Genes vary in size from about 100 to 2.5million base pairs. The length of
the sequence of DNA and the precise order of the base pairs in a gene are the
critical factors that determine what the gene product (usually a protein) will
be like and what it will do in a cell.
5. INTRODUCTION
• The term “prokaryote” means “primitive nucleus”. Cell in prokaryotes have no
nucleus. The prokaryotic chromosome is dispersed within the cell and is not
enclosed by a separate membrane.
• Much of the information about the structure of DNA has come from studies of
prokaryotes, because they are less complex (genetically and biochemically)
than eukaryotes.
• Prokaryotes are monoploid = they have only one set of genes (one copy of the
genome).
• In most viruses and prokaryotes, the single set of genes is stored in a single
chromosome (single molecule either RNA or DNA).
• Prokaryotic genomes are exemplified by the E. coli chromosome.
• The bulk of the DNA in E. coli cells consists of a single closed-circular DNA
molecule of length 4.6 million base pairs.
• The DNA is packaged into a region of the cell known as the nucleoid.
6. DNA domains
• Experiments in which DNA from E.
coli is carefully isolated free of most
of the attached proteins and observed
under the electron microscope reveal
one level of organization of the
nucleoid.
• The DNA consists of 50–100 domains
or loops, the ends of which are
constrained by binding to a structure
which probably consists of proteins
attached to part of the cell membrane.
The loops are about 50–100 kb in size.
7. Supercoiling of the genome
• The E. coli chromosome as a whole is negatively supercoiled,
although there is some evidence that individual domains may be
supercoiled independently.
• Electron micrographs indicate that some domains may not be
supercoiled, perhaps because the DNA has become broken in one
strand, where other domains clearly do contain supercoils.
• The attachment of the DNA to the protein–membrane scaffold may
act as a barrier to rotation of the DNA, such that the domains may be
topologically independent.
8. DNA-binding proteins
• The most abundant of these are protein HU, a small basic (positively charged) protein.
• It’s binds DNA nonspecifically by the wrapping of the DNA around the protein, and H-NS
(formerly known as protein H1), a monomeric neutral protein, which also binds DNA
nonspecifically in terms of sequence. These proteins are sometimes known as histone-like
proteins, and have the effect of compacting the DNA, which is essential for the packaging
of the DNA into the nucleoid, and of stabilizing and constraining the supercoiling of the
chromosome.
• Half of this is constrained as permanent wrapping of DNA around proteins such as HU.
Only about half the supercoiling is unconstrained.
• RNA polymerase and mRNA molecules, site-specific DNA-binding proteins such as
integration host factor (IHF), a homolog of HU, which binds to specific DNA sequences
and bends DNA through 140 .
11. INTRODUCTION
• In humans the average DNA molecule is about 6.5x107 base pairs in length.
• The nucleus of a human cells is just 6mm in diameter, yet it contains 1.8m of DNA.
• This can only be achieved because DNA in eukaryotes is tightly packaged into
chromosomes.
• DNA is coiled around small proteins (histones).
• Where the DNA is wrapped around a core of histone proteins it forms a particle about
10nm in diameter called a nucleosome.
• The nucleosomes give the DNA strand the appearance of a string of beads, and this
arrangement of DNA wrapped around histones serves to package the DNA efficiently and
protected from enzymatic degradation.
• When a eukaryotic cell is preparing to divide, chromosomes become very condensed and
are visible under a light microscope.
12.
13. Chromatin
Chromatin is isolated from interphase nuclei, the individual
chromosomes are not recognizable. Instead one observes an irregular
aggregate of nucleoprotein. Chemical analysis of isolated chromatin
shows that it consists primarily of DNA and proteins and lesser amounts
of RNA.
This proteins are two major classes:
Basic proteins-positively charged at neutral pH called histones.
A heterogeneous largely acidic (negatively charged at neutral pH) group
of proteins collectively referred to as non-histone chromosomal
proteins.
14. Histones
• The major protein components of chromatin are the histones. Most of the
protein in eukaryotic chromatin consists of histones.
• Five families, or classes of histones:
• H2A, H2B, H3 and H4: core histones. The core histones are small
proteins, with masses between 10 and 20 kDa.
• H1: little larger at around 23 kDa.
• All histone proteins have a large positive charge; between 20 and 30%
of their sequences consist of the basic amino acids, lysine and arginine.
• This means that histones will bind very strongly to the negatively
charged DNA in forming chromatin.
15. 10 nm filament; nucleosomes
protein
purification
histones
(= 1g per g DNA)
H1 •Basic (arg, lys);
•+ charges bind
H3 to - phosphates
H2A on DNA
H2B
H4
DNA
16. • Members of the same histone class are very highly conserved between
relatively unrelated species, ex: between plants and animals, which
testifies to their crucial role in chromatin.
• H1 histones are somewhat distinct from the other histone classes in a
number of ways; in addition to their larger size, there is more variation
in H1 sequences both between and within species than in the other
classes.
17. 1. DNA compacting ratio
2. Nucleosomes
I) Ultrastructure of nucleosome core protein
II) Bonding between histone core and DNA
III) Bending of DNA in a nucleosome
IV) Packing of nucleosomes into compact chromatin fiber.
18. DNA compaction ratio
• Human chromosome 22 contains about 48 million nucleotide pairs.
Stretched out end to end, its DNA extend about 1.5 cm.
• Chromosome 22 measures only about 2µm in length, giving end-toend compaction ration of nearly 10,000 fold.
• Compression is performed by proteins.
19. Nucleosomes
• The basic unit of chromatin is the nucleosome. The nucleosome is
composed of approximately 146 base pairs of DNA wrapped in 1.8
helical turns around an eight-unit structure called histone protein
octamer.
• This histone octamer consists of two copies each of the histones H2a,
H2b, H3, and H4.
• The space in between individual nucleosomes is referred to as linker
DNA, and can range in length from 8 to 114 base pairs, with 55 base
pairs being the average.
• Linker DNA interacts with the linker histone, called H1.
20.
21.
22. Bonding between histone core and DNA
• About 142 hydrogen bonds are formed between DNA and the histone
core in each nucleosome. Nearly half of these bonds form between the
aminoacid backbone of the histones and phosphodiester bonds of
DNA.
• For example: all core histones are rich in lysine and arginine.
• positive charge of these aminoacids can effectively neutralized the
negatively charged DNA backbone.
23. Bending of DNA in a nucleosome
• Two main influences determine where nucleosomes form in the DNA:
• Difficulty of bending: bending of the DNA double helix into two tight
turns around the outside of the histone octamer, a process that required
firm compression of the minor groove of the DNA helix.
• A-T rich sequences in the minor groove are easier to compress than GC rich sequences.
• The presence of certain other tightly bound proteins on the DNA also
influences the position of nucleosomes on DNA molecule.
28. The bending of DNA in a nucleosome
1. Flexibility of DNAs: A-T riched minor groove inside and G-C riched groove outside
2. DNA bound protein can also help
35. Covalent Modification of core
histone tails
Acetylation of lysines
Mythylation of lysines
Phosphorylation of serines
Histone acetyl transferase (HAT)
Histone deacetylase (HDAC)
36.
37.
38. Eukaryotes
Prokaryotes
Location of Chromosomes
In the nucleus
In the cytoplasm
Structure of Chromosomes
Double stranded molecules of
DNA, with attached protein
molecules.
Single, circular chromosome
composed of DNA, with very few
or no attached proteins.
Number of Chromosomes
Varies from species to species.
Humans have 46.
One.
Reproduction
Nuclear DNA is replicated prior
to cell division and the
chromosomes distributed evenly
to daughter cells.
Single circular chromosome is
replicated prior to cell division.
Each daughter cell receives one
copy of this chromosome.
Extra-chromosomal DNA
Mitochondria contain DNA.
Small circular DNA molecules
known as plasmids.