Trilobites are extinct group in fossil record TimeMarkers
Biozone markers
Paleoclimatic indicators Stratigraphic boundarymarkers Significance in Phylogenic studies
Good time markers in Cambrian-Permianas
Index fossils
Short lived but long and significant markers in Stratigraphic studies.
MORPHOLOGY AND SIGNIFICANCE OF CONODONT (group-D).pptxKuki Boruah
Conodonts are marine organism ranging from Cambrian to Triassic periods, having a long wormlike body, numerous small teeth and a pair of eyes.
It is now believed as the earliest vertebrate and now it is an extinct group of organism.
First identified by the LATVIAN embryologist and palaeontologist Christian Pander in 1856.
Conodonts are most frequently occuring fossil in marine Sedimentary Rocks.
Size of Conodonts commonly in between 200 microns and 5 millimetres.
The preserved color varying from translucent and colorless through light brown to black.
Brief description on Phylum Brachiopods with general terms used for Paleontology.
Structure paleoecology, geography, morphology.
And also easily understandable as since it discuss only specific terms only.
MORPHOLOGY AND SIGNIFICANCE OF CONODONT (group-D).pptxKuki Boruah
Conodonts are marine organism ranging from Cambrian to Triassic periods, having a long wormlike body, numerous small teeth and a pair of eyes.
It is now believed as the earliest vertebrate and now it is an extinct group of organism.
First identified by the LATVIAN embryologist and palaeontologist Christian Pander in 1856.
Conodonts are most frequently occuring fossil in marine Sedimentary Rocks.
Size of Conodonts commonly in between 200 microns and 5 millimetres.
The preserved color varying from translucent and colorless through light brown to black.
Brief description on Phylum Brachiopods with general terms used for Paleontology.
Structure paleoecology, geography, morphology.
And also easily understandable as since it discuss only specific terms only.
Graptolites is an important index fossil for Paleozoic rocks and common throughout the world. As in Pakistan the sequences from the Ordovician to carboniferous age missing but these strata are exist in Noshehra and Chitral, so thats why its more valuable as regional fossil of sub-continent.
K t boundary and Probable causes of Dinosour extinctionTahsin Islam Ornee
It describes about K-T Boundary and the probable causes of the mass extinction in K-T boundary. It includes some proves that shows that extra terrestrial impact caused Dinosaur extinction.
Graptolites is an important index fossil for Paleozoic rocks and common throughout the world. As in Pakistan the sequences from the Ordovician to carboniferous age missing but these strata are exist in Noshehra and Chitral, so thats why its more valuable as regional fossil of sub-continent.
K t boundary and Probable causes of Dinosour extinctionTahsin Islam Ornee
It describes about K-T Boundary and the probable causes of the mass extinction in K-T boundary. It includes some proves that shows that extra terrestrial impact caused Dinosaur extinction.
A presentation about Arthropods, its general morphology, life cycle, and habitat. This presentation also covers the first three subphyla which are Trilobitomorpha, Chelicerata, and Crustacea. The role of arthropods in disease transmission is also covered in the slides.
Arthropoda is the largest and most successful phylum in the world. Here are the slides that can help you understand the basics of this phylum.
Hope it will be helpful for you!
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
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 .
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.
Richard's entangled aventures in wonderlandRichard 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.
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.
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.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
2. • Trilobites are hard-shelled, segmented creatures that
existed over 300 million years ago.
• Trilobites were among the first of arthropods(a phylum
of hard-shelled creatures with multiple body segments
and jointed legs).
• They belong to class Trilobita(9 orders, over 150
families, thousands of genera, over 15,000 described
species.
• The smallest known trilobite is just over a millimeter
long, while the largest include species from 30-70 cm in
length.
• •Life styles of trilobites include planktonic, swimming,
and crawling forms (predators and scavengers). 'Most
trilobites are about an inch long.
3.
4. TRILOBITE MORPHOLOGYTRILOBITE MORPHOLOGY
• Trilobites is divided across the body into a head (or cephalon), thorax, and
tail (or pygidium), and along the body into three lobes - a central axial lobe
covering the main body cavity, and two pleural lobes covering the legs and gills
on either side.
• The head, or cephalon, was generally large relative to the rest of the body,
and is usually divided into a series of sections separated by sutures that
facilitated molting. These sutures form a small number of distinctive patterns
across the cephalon.
• The section of the head outside the facial sutures is known as the free
cheek. The part inside, adjacent to the glabella, is called the fixed cheek. The
eyes of the trilobite could attach to either the free or fixed parts of the
cephalon.
• The eyes of trilobites were typically large and compound, made from multiple
lenses like the eyes of flies. Eyes in arthropods have evolved several times,
and those in trilobites are unique to the group. They had very clear vision,
often using the physical characteristics of calcite to enhance light capture
and focus. The visual range of trilobites was very variable, and appears
strongly related to their mode of life.
• Running down the middle of the head is the glabella, a raised region that
protected the stomach. The size of the glabella correlated to the size of the
stomach, and furrows that partly ran across the glabella may be the external
expression of internal ridges, to which ligaments supporting the stomach were
attached. The mouth is situated underneath the cephalon, near the back of
the head, and is associated with a plate of cuticle called the hypostome. This
could be attached to the front of the cephalon, or could be free lying within
the soft cuticle of the underside ofthe trilobite
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• The Thorax of a typical trilobite was made up of a series of nearly
identical segments, usually between two and 20 in number. Below
each of these was a pair of legs and gills. In Ordovician and later
trilobites these segments were usually jointed in such a way that
the trilobite could roll up for defense
• The Trilobite tail, or pygidium, was usually small and made up of a
series of fused segments that look similar to those on the thorax.
It is likely that the leg/gill pairs occurred under some segments of
the tail in most trilobites, though in some species these segments
may have lacked limbs.
• Glabella: a raised central area of the head under which IS the
stomach compound eye
• Facial suture: a natural break in the exoskeleton to facilitate
molting
• Segments: below each segment is a limb/gill pair
• Hypostome: mouth located at rear. In Calymene the hypostome is
fixed to the front of the cephalon.
• Central groove between legs: food is probably manipulated by the
legs into this groove and then moved to the mouth. The first leg
segments are serrated to provide gripping and tearing functions.
• Leg/gill pairs: one pair for each segment in the thorax, probably
three under the cephalon and several vestigial ones under the
pygidium
16. • They thrived for almost 300 million years, from the Lower
Cambrian (521 million years ago) to the start of the Mesozoic
(250 million years ago). That means their period was
hundreds of millions of years earlier than the Jurassic, when
dinosaurs ruled the Earth.
• Trilobites are extinct arthropods, and some of the earliest
one at that. They are distant relatives of modern lobsters and
spiders.
• They lived in marine waters, although only some of them
could actually swim. Many burrowed or crawled around on
muddy sea floors.
• They were the first creatures to develop complex eyes.
17. •Trilobites are extinct group in fossil
record
•Time Markers
•Biozone markers
•Paleoclimatic indicators
•Stratigraphic boundarymarkers
•Significance in Phylogenic studies
•Good time markers in Cambrian
Permian as Index fossils
•Short lived but long and significant
markers in Stratigraphic studies.
