DNA carries genetic instructions in all living things. It is a double-stranded molecule shaped like a twisted ladder. Each strand has a backbone made of sugar and phosphate, with nitrogen bases (A, T, C, G) forming rungs between the strands via hydrogen bonding. The structure was discovered in 1953 by Watson and Crick. DNA is found in the cell nucleus and mitochondria, where it stores and transmits hereditary information from parents to offspring that directs protein synthesis and cell functions.
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
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
Microbial genetics is a subject area within microbiology and genetic engineering. This involves the study of the genotype of microbial species and also the expression system in the form of phenotypes
Microbial genetics is a subject area within microbiology and genetic engineering. This involves the study of the genotype of microbial species and also the expression system in the form of phenotypes
Unit 1 genetics nucleic acids DNA (1) Biology aid Lassie sibanda
These slides will help those who love biology but yet find it so hard to break down see how easy and interesting life science is. hope these improve your knowledge
DNA is the largest molecule known. A single, unbroken strand of it can contain many millions of atoms. When released from a cell, DNA typically breaks up into countless fragments. In solutions, these strands have a slight negative electric charge, a fact that makes for some fascinating chemistry.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
2. What is DNA?
“DNA is a group of molecules that is responsible for
carrying and transmitting the hereditary materials or the
genetic instructions from parents to offsprings.”
• DNA stands for Deoxyribonucleic Acid which is a molecule
that contains the instructions an organism needs to develop,
live and reproduce.
• These instructions are found inside every cell and are
passed down from parents to their children.
• It is a nucleic acid and is one of the four major types of
macromolecules that are known to be essential for all forms
of life.
• DNA is found in the nucleus, with a small amount of DNA
also present in mitochondria in the eukaryotes.
4. • In 1953, James Watson and Francis Crick discovered
the structure of DNA.
• The works of Rosalind Franklin lead to Watson and Crick’s
discovery. Franklin first had pointed out that the DNA is made up
of two spirals.
• The structure of DNA is a double helix structure because it looks
like a twisted ladder.
• The sides of the ladder are made of alternating sugar
(deoxyribose) and phosphate molecules while the steps of the
ladder are made up of a pair of nitrogen bases.
• There are 4 types of nitrogen bases Adenine (A) Thymine (T)
Guanine (G) Cytosine (C) DNA Pairing. The nitrogen bases have
a specific pairing pattern.
• This pairing pattern occurs because the amount of adenine
equals the amount of thymine; the amount of guanine equals
the amount of cytosine. The pairs are held together by
hydrogen bonds.
5.
6. • DNA is a double-stranded helix.
• That is each DNA molecule is comprised of two biopolymer
strands coiling around each other to form a double helix
structure.
• These two DNA strands are called polynucleotides, as they
are made of simpler monomer units called nucleotides.
• Each strand has a 5′end (with a phosphate group) and a
3′end (with a hydroxyl group).
• The strands are antiparallel, meaning that one strand runs
in a 5′to 3′direction, while the other strand runs in a 3′ to 5′
direction.
• The two strands are held together by hydrogen bonds and
are complimentary to each other.
• Basically, the DNA is composed of deoxyribonucleotides.
7. • The deoxyribonucleotides are linked together by 3′ –
5′phosphodiester bonds.
• The nitrogenous bases that compose the deoxyribonucleotides
include adenine, cytosine, thymine, and guanine.
• The complimentary of the strands are due to the nature of the
nitrogenous bases.
• The base adenine always interacts with a thymine (A-T) on the
opposite strand via two hydrogen bonds and cytosine always
interacts with guanine (C-G) via three hydrogen bonds on the
opposite strand.
• The shape of the helix is stabilized by hydrogen bonding and
hydrophobic interactions between bases.
• The diameter of double helix is 2nm and the double helical
structure repeats at an interval of 3.4nm which corresponds
to ten base pairs.
8. Major and Minor Grooves of the DNA
• As a result of the double helical nature of DNA, the molecule has
two asymmetric grooves. One groove is smaller than the other.
• This asymmetry is a result of the geometrical configuration of the
bonds between the phosphate, sugar, and base groups that forces
the base groups to attach at 120 degree angles instead of 180
degree.
• The larger groove is called the major groove, occurs when the
backbones are far apart; while the smaller one is called the minor
groove, occurs when they are close together.
• Since the major and minor grooves expose the edges of the bases,
the grooves can be used to tell the base sequence of a
specific DNA molecule.
• The possibility for such recognition is critical, since proteins must
be able to recognize specific DNA sequences on which to bind in
order for the proper functions of the body and cell to be carried
out.
9. Properties of DNA
• DNA helices can be right handed or left handed. But the B –
conformation of DNA having the right handed helices is the
most stable.
• On heating the two strands of DNA separate from each other
and on cooling these again hybridize.
• The temperature at which the two strands separate
completely is known as melting temperature (Tm). Melting
temperature is specific for each specific sequence.
• The B sample of DNA having higher melting point must have
more C-G content because C-G pair has 3 hydrogen bonds.
• The sequence of bases along the DNA molecule encodes for
the sequence of amino acids in every protein in all
organisms.
10. Types of DNA
• Eukaryotic organisms such as animals, plants and fungi,
store the majority of their DNA inside the cell nucleus and
some of their DNA in organelles such as mitochondria.
• Based on the location DNA may be
• Nuclear DNA
• Located within the nucleus of eukaryote cells.
• Usually has two copies per cell.
• The structure of nuclear DNA chromosomes is linear with
open ends and includes 46 chromosomes containing 3
billion nucleotides.
• Nuclear DNA is diploid, ordinarily inheriting the DNA from
two parents. The mutation rate for nuclear DNA is less than
0.3%.
11. Mitochondrial DNA
• Mitochondrial DNA is located in the mitochondria.
• Contains 100-1,000 copies per cell.
• Mitochondrial DNA chromosomes usually have closed,
circular structures, and contain for example 16,569
nucleotides in human.
• Mitochondrial DNA is haploid, coming only from the mother.
• The mutation rate for mitochondrial DNA is generally higher
than nuclear DNA.
13. • Most of the DNA is in the classic Watson-Crick model simply
called as B-DNA or B-form DNA.
• In certain condition, different forms of DNAs are found to be
appeared like A-DNA,Z-DNA,C- DNA,D-DNA,E-DNA.
• This deviation in forms are based on their structural diversity.
• B-DNA
• Most common, originally deduced from X-ray diffraction of
sodium salt of DNA fibres at 92% relative humidity.
• A-DNA
• Originally identified by X-ray diffraction of analysis of DNA fibres
at 75% relative humidity.
• Z-DNA
• Left handed double helical structure winds to the left in a zig- zag
pattern.
• .
14. • C-DNA
• Formed at 66% relative humidity and in presence of Li+ and
Mg2+ ions.
• D-DNA
• Rare variant with 8 base pairs per helical turn, form in
structure devoid of guanine
• E- DNA
• Extended or eccentric DNA.
15. Functions of DNA
• DNA has a crucial role as genetic material in most living
organisms. It carries genetic information from cell to cell
and from generation to generation.
• Thus its major functions include:
• Storing genetic information
• Directing protein synthesis
• Determining genetic coding
• Directly responsible for metabolic activities, evolution,
heredity, and differentiation.
• It is a stable molecule and holds more complex information
for longer periods of time.
16. References
• Bailey, W. R., Scott, E. G., Finegold, S. M., & Baron, E. J.
(1986). Bailey and Scott’s Diagnostic microbiology. St. Louis:
Mosby.
• http://www.differencebetween.net/science/difference-
between-mitochondrial-dna-and-nuclear-dna/
• https://en.wikibooks.org/wiki/Structural_Biochemistry/Nu
cleic_Acid/DNA/DNA_structure#Major_and_Minor_Grooves
• https://microbenotes.com/dna-structure-properties-types-
and-functions/