The document discusses the origin of the first cells. It begins by explaining that cells can only arise from the division of pre-existing cells, and that the first cells must have originated from non-living material on Earth. It then describes several key steps in the emergence of early life, including the synthesis of organic molecules, their assembly into polymers, the formation of membranes, and the development of molecules that could self-replicate like RNA. The document also discusses evidence supporting these events, such as the Miller-Urey experiment. Finally, it explains the endosymbiotic theory for the origin of eukaryotic cells, where mitochondria and chloroplasts arose through the engulfment and retention of ancient bacteria.
Structure and function of plasma membrane 2ICHHA PURAK
The presentation consists of 72 slides,describes following heads
DEFINITION : STRUCTURE OF PLASMA MEMBRANE
COMPONENTS OF PLASMA MEMBRANE ( (BIOCHEMICAL PROPERTIES)
LIPID BILAYER
PROTEINS
CARBOHYDRATES
CHOLESTEROL
MODELS EXPLAINING STRUCTURE OF BIO MEMBRANE
FLUID MOSAIC MODEL
MOBILITY OF MEMBRANE
GLYCOCALYX : GLYCOPROTEINS AND GLYCOLIPIDS
TRANSPORT OF IONS AND MOLECULES ACROSS PLASMA MEMBRANE
FUNCTIONS OF PLASMA MEMBRANE
DIVERSITY OF CELL MEMBRANES
SITE OF ATPASE ION CARRIER CHANNELS AND PUMPS-RECEPTORS
Structure and function of plasma membrane 2ICHHA PURAK
The presentation consists of 72 slides,describes following heads
DEFINITION : STRUCTURE OF PLASMA MEMBRANE
COMPONENTS OF PLASMA MEMBRANE ( (BIOCHEMICAL PROPERTIES)
LIPID BILAYER
PROTEINS
CARBOHYDRATES
CHOLESTEROL
MODELS EXPLAINING STRUCTURE OF BIO MEMBRANE
FLUID MOSAIC MODEL
MOBILITY OF MEMBRANE
GLYCOCALYX : GLYCOPROTEINS AND GLYCOLIPIDS
TRANSPORT OF IONS AND MOLECULES ACROSS PLASMA MEMBRANE
FUNCTIONS OF PLASMA MEMBRANE
DIVERSITY OF CELL MEMBRANES
SITE OF ATPASE ION CARRIER CHANNELS AND PUMPS-RECEPTORS
A prelude to genetics of Mitochondria and Chloroplasts
the theory provides an explanation for the presence and source of organellar genome in eukaryotic cell
It presents the history of the Earth through geologic time. It discusses the earth's structure, composition, and processes. Issues, concerns, and problems pertaining to natural hazards are also included. It also deals with the basic principles and processes in the study of biology.
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.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
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 .
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.
1. 1.5 Origin of cells
Essential idea: There is an unbroken chain of life from the
first cells on Earth to all cells in organisms alive today.
Two billion year old prokaryotic fossils of cells. https://c1.staticflickr.com/9/8187/8117548368_0615009f66_b.jpg
2. Understandings, Applications and Skills
Statement Guidance
1.5 U.1 Cells can only be formed by division of pre-
existing cells.
Students should be aware that the 64
codons in the genetic code have the same
meanings in nearly all organisms, but that
there are some minor variations that are
likely to have accrued since the common
origin of life on Earth.
1.5 U.2 The first cells must have arisen from non-living
material.
1.5 U.3 The origin of eukaryotic cells can be explained by
the endosymbiotic theory.
Evidence for the endosymbiotic theory is
expected. The origin of eukaryote cilia and
flagella does not need to be included.
1.5 A.1 Evidence from Pasteur’s experiments that
spontaneous generation of cells and organisms
does not now occur on Earth.
3. Use the tutorials to learn about Pasteur’s
experiment.
1.5 A.1 Evidence from Pasteur’s experiments that spontaneous generation of
cells and organisms does not now occur on Earth.
Repeat Pasteur’s experiment and
see the results for yourself.
http://biologyjunction.com/pasteur_experiment.ht
m
http://www.sumanasinc.com/webcontent/animations/content/scientifi
cmethod.html
4. 1.5 A.1 Evidence from Pasteur’s experiments that spontaneous
generation of cells and organisms does not now occur on Earth.
http://bcs.whfreeman.com/thelifewire/content/chp03/0302003.html
5. 1.5 A.1 Evidence from Pasteur’s experiments that spontaneous
generation of cells and organisms does not now occur on Earth.
Method:
• Two experiments were setup
• In both, Pasteur added nutrient broth to
flasks and bent the necks of the flasks into S
shapes
• Each flask was then heated to boil the broth
in order than all existing microbes were
killed.
• After the broth had been sterilized, Pasteur
broke off the swan necks from the flasks in
Experiment 1, exposing the nutrient broth
within them to air from above.
• The flasks in Experiment 2 were left alone.
Results:
• The broth in experiment 1 turned
cloudy whilst the broth in experiment
2 remained clear.
• This indicates that microbe growth
only occurred in experiment 1.
Conclusion: Pasteur rejected
the hypothesis of
spontaneous generation as for
growth of microbes to occur a
source of contamination was
needed.
Louis Pasteur designed an experiment to test
whether sterile nutrient broth could
spontaneously generate microbial life.
Q – was Pasteur correct, could
spontaneous generation of life
never occur?
6. 1.1 U.1 According to the cell theory, living organisms are composed of
cells.
Cell theory states that:
• All living things are composed of cells (or cell products)
• The cell is the smallest unit of life
• Cells only arise from pre-existing cells
7. 1.5 U.1 Cells can only be formed by division of pre-existing cells.
Cells can only be formed by
division of pre-existing cells:
• Cells multiply through division
• Mitosis results in genetically identical
diploid daughter cells
• Meiosis generates haploid gametes
(sex cells)
4-cell stage of a sea biscuit by Bruno Vellutini on Flickr
(CC) http://flic.kr/p/daWnnS
8. What evidence do we have
(other than Pasteur’s
experiments) to support this
theory?
4-cell stage of a sea biscuit by Bruno Vellutini on Flickr
(CC) http://flic.kr/p/daWnnS
9. 1.5 U.1 Cells can only be formed by division of pre-existing cells.
1. Cells are highly complex
structures and no mechanism has
been found for producing cells
from simpler subunits.
http://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Eukaryotic_Cell_%28animal%29.jpg/1024px-Eukaryotic_Cell_%28animal%29.jpg
10. 1.5 U.1 Cells can only be formed by division of pre-existing cells.
2. All known examples of growth
from cell to tissue, tissue to organ,
organ to multicellular organism,
are all a result of cell division.
http://upload.wikimedia.org/wikipedia/commons/thumb/d/d3/Onion_root_mitosis.jpg/749px-Onion_root_mitosis.jpg
11. 1.5 U.1 Cells can only be formed by division of pre-existing cells.
3. Viruses are produced from simpler
subunits, but they do not consist of cells,
and they can only be produced inside the
host cells that they have infected.
http://upload.wikimedia.org/wikipedia/commons/3/3a/Influenza_virus_particle_color.jpg
12. 1.5 U.1 Cells can only be formed by division of pre-existing cells.
4. Genetic code is universal each
of the 64 codons (a codon is a
combination of 3 DNA bases)
produces the same amino acid in
translation, regardless of the
organism [2.7.A2]*.
* There are some minor variations that are likely to have accrued since the common origin of
life on Earth, but these are rare and most of the genetic code is universal most of the time.
The logical deduction is that all
cells have arisen as the result of
cell division from a single
common ancestor.
13. There were times in the history of the Earth when cells did not exist.
The first cells must have arisen from non-living material or life was
transported here from elsewhere in the universe. As illustrated below,
an asteroid may have carried the first cells (panspermia). We will
focus on the organic evolution from materials on Earth.
1.5 U.2 The first cells must have arisen from non-living material.
Some of the key problems are:
1. Non-living synthesis of simple organic
molecules, e.g. sugars and amino
acids
2. Assembly of these organic molecules
into polymers
3. Formation of membranes to package
the organic molecules
4. Compartmentalization by formation
of polymers that can self-replicate
(enabling inheritance)
14. Prebiotic Chemistry/Earth
• Little or no free oxygen
Oxygen very reactive, would remove electrons needed for
reactions
• Considerable energy
Heat, light, electrical energy needed to make/break bonds
Vulcanism, sun provided much UV, lightning
• Chemical ‘building blocks’ to be built into more complex molecules
• The reactions required time ~ 0.8 billion years to cause life to come
about. This is a long time, but not long compared to the life of the
Universe (~10-20 billion years)
1.5 U.2 The first cells must have arisen from non-living material.
15. 1. Non-living synthesis of simple organic molecules
(Materials available in the Prebiotic Earth)
• All living things have the same overall chemistry
– Suggests a common origin
– However, likely to be multiple similar origins
• Earth ~ 4.5 billion years old
• Early atmosphere:
» H2O vapor
» NH3
» N2
» H2
» H2S
» CH4
» Virtually no O2
1.5.U.2 The first cells must have arisen from non-living material.
17. 2. Assembly of these organic
molecules into polymers
(Miller / Urey Experiment)
• Created an ancient earth
atmosphere in globes
– H2O vapor
– H2
– NH3
– CH4
• Electrical discharge
• Heated via mantle in lower
chamber
• Paper chromatography showed
that 13 of the 20 amino acids had
formed
• Similar experiments have shown
that all 20 amino acids, lipids,
nucleotide bases, and ATP, if
phosphate present.
18.
19. 1.5 U.2 The first cells must have arisen from non-living material.
Primitive ‘Soup’ (ocean surface)
• Haldane and Oparin (~1920s)
proposed that life arose from
nonliving conditions by means of a
series of changes (and increasing
complexity) in molecular
composition as a result of the
reducing, high energy environment
that existed on early Earth
(between 4.6-3.8 bybp (billion
years before present)
• Proposed the Prebiotic Broth
Hypothesis
• Not tested until 1950s
• Tested by Stanley Miller and
Harold Urey
20. • An addition to the theory that life
may have formed close to the
oceans surface, early life may have
formed at hydrothermal vents on
the ocean floor
• Today, hydrothermal vents provide
basic materials to support living
organisms in environments where
there is no light, very little energy,
and little other perturbation
• Ammonia is produced in
abundance at such locations,
suggesting that it could possibly
be built into nucleic acid bases
and the possibly into amino acids
http://faculty.cascadia.edu/jvanleer/astro%20sum01/Hyrothremal%20Ven
t%20Final/hydrothermal-vent.jpg
22. 1.5 U.2 The first cells must have arisen from non-living material.
• DNA though very stable
and effective at storing
information is not able to
self-replicate – enzymes
are required
• However RNA can both
store information and self-
replicate - it can catalyze
the formation of copies of
itself.
• In ribosomes RNA is found
in the catalytic site and
plays a role in peptide
bond formation
For more detail research the RNA World Hypothesis
3. Formation of polymers that can self-replicate (enabling inheritance)
23. •The current “most accepted“ theory of life evolving hypothesizes an
RNA world
•RNA in the early world would have functioned as a self replicating
molecule, eventually developing a number of minimal catalytic
properties
self-replicates Proteins take
over catalysis
DNA becomes
long term storage
and major coding molecule
Packaging evolves
- RNA codes
and catalyses
RNA
Molecular Reproduction
24. The RNA World Hypothesis
• Proposed by Walter Gilbert, mid 1980s
• Concept of RNA catalyzing critical pre-biotic and early biological
reactions
• RNA would give rise to RNA as an informational molecule
• RNA would give rise to protein
• RNA might bind amino acids proteins
• RNA might give rise to DNA
• Proteins might take over some functions
• DNA would take over informational functionality
• Eventually giving rise to the DNA RNA protein scheme
found today
25. 1.5 U.2 The first cells must have arisen from non-living material.
4. Compartmentalization
The formation of membranes to
package the organic molecules.
Experiments have shown that
phospholipids natural assemble
into bilayers, if conditions are
correct.
Formation of the bilayer creates
an isolated internal environment.
The formation of an internal
environment means that optimal
conditions, e.g. for replication or
catalysis can be maintained.
Two ideas
A. Microsphere
B. Ocean froth
http://upload.wikimedia.org/wikipedia/commons/thumb/0/
01/Liposome_scheme-en.svg/220px-Liposome_scheme-
en.svg.png
26. Origin of Cells (Protobionts)
• Bubbles separate inside from outside
metabolism & reproduction
27. Microspheres (coacervates)
Formed from heated mixtures of amino acids
Subsequently mixed with salty water
Some are excitable
Have some catalytic activity
Could provide the separation for increasing the concentration of
material required for early prebiotic chemistries
28. Ocean Froth
• The waves crashing on
the shore consisted of
bubbles (froth)
• The “membranes” of the
bubble were either
made of
– hydrocarbon chains/lipids
– Protenoids (chains of
amino acids)
29. http://youtu.be/q71DWYJD-dI
1.5 U.3 The origin of eukaryotic cells can be explained by the
endosymbiotic theory.
Endosymbiotic theory explains the existence of several organelles of eukaryotes.
The theory states that the organelles (e.g. mitochondria and chloroplasts)
originated as symbioses between separate single-celled organisms,
http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter26/animation_-_endosymbiosis.html
30. First Eukaryotes (about 2 billion years ago)
• Development of internal membranes
– create internal micro-environments
– advantage: specialization = increase efficiency
• natural selection!
infolding of the
plasma membrane
DNA
cell wall
plasma
membrane
Prokaryotic
cell
Prokaryotic
ancestor of
eukaryotic
cells
Eukaryotic
cell
endoplasmic
reticulum (ER)
nuclear envelope
nucleus
plasma
membrane
31. Endosymbiosis
Ancestral
eukaryotic cell
Eukaryotic cell
with mitochondrion
internal membrane
system
aerobic bacterium mitochondrion
Endosymbiosis
• Evolution of eukaryotes
– origin of mitochondria
– engulfed aerobic bacteria, but did not digest them
– mutually beneficial relationship
• natural selection!
32. mitochondrion
chloroplast
Eukaryotic cell with
chloroplast & mitochondrion
Endosymbiosis
photosynthetic
bacterium
• Evolution of eukaryotes
– origin of chloroplasts
– engulfed photosynthetic bacteria,
but did not digest them
– mutually beneficial relationship
• natural selection!
Eukaryotic
cell with
mitochondrion
33. • Evidence
– structural
• mitochondria & chloroplasts
resemble bacterial structure
– genetic
• mitochondria & chloroplasts
have their own circular DNA, like
bacteria
– functional
• mitochondria & chloroplasts
move freely within the cell
• mitochondria & chloroplasts
reproduce independently
from the cell
Theory of Endosymbiosis
lynn margulis