Cytoskeleton - microtubules ,microfilaments and intermediate filamentsBIOTECH SIMPLIFIED
The cytoskeleton is a structure that helps cells maintain their shape and internal organization, and it also provides mechanical support that enables cells to carry out essential functions like division and movement. There is no single cytoskeletal component. Rather, several different components work together to form the cytoskeleton.
Structure and functions of endoplasmic reticulumICHHA PURAK
The presentation consists of 57 slides,describes following heads
• DISCOVERY
• INTRODUCTION
• BIOGENESIS OF ER
• ISOLATION OF MICROSOMES FROM E R
• STRUCTURE
• COMPONENTS OF ER
CISTERNAE
VESICLES
TUBULES
• MAIN FUNCTION OF ER
• TYPES OF ENDOPLASMIC RETICULUM
• SMOOTH ENDOPLASMIC RETICULUM (SER)
• FUNCTIONS OF SER
• ROUGH ENDOPLASMIC RETICULUM (RER)
• FUNCTIONS OF RER
• SUMMARY
• REFERENCES
• QUESTIONS
The delivery of newly synthesized protein to their proper cellular destination, usually referred to as protein targeting or sorting.
The mode of protein transport depends chiefly on the location in the cell cytoplasm of the polysomes involved in protein synthesis.
There are two modes of protein sorting:-
1) Co - translational Transportation.
2) Post - translational Transportation.
Cytoskeleton - microtubules ,microfilaments and intermediate filamentsBIOTECH SIMPLIFIED
The cytoskeleton is a structure that helps cells maintain their shape and internal organization, and it also provides mechanical support that enables cells to carry out essential functions like division and movement. There is no single cytoskeletal component. Rather, several different components work together to form the cytoskeleton.
Structure and functions of endoplasmic reticulumICHHA PURAK
The presentation consists of 57 slides,describes following heads
• DISCOVERY
• INTRODUCTION
• BIOGENESIS OF ER
• ISOLATION OF MICROSOMES FROM E R
• STRUCTURE
• COMPONENTS OF ER
CISTERNAE
VESICLES
TUBULES
• MAIN FUNCTION OF ER
• TYPES OF ENDOPLASMIC RETICULUM
• SMOOTH ENDOPLASMIC RETICULUM (SER)
• FUNCTIONS OF SER
• ROUGH ENDOPLASMIC RETICULUM (RER)
• FUNCTIONS OF RER
• SUMMARY
• REFERENCES
• QUESTIONS
The delivery of newly synthesized protein to their proper cellular destination, usually referred to as protein targeting or sorting.
The mode of protein transport depends chiefly on the location in the cell cytoplasm of the polysomes involved in protein synthesis.
There are two modes of protein sorting:-
1) Co - translational Transportation.
2) Post - translational Transportation.
Details of cytoskeleton element-microtubule. The Microtubule associated protein-type and function, Treadmilling and dynamic instability, Structure of cilia and flagella
Details of cytoskeleton element-microtubule. The Microtubule associated protein-type and function, Treadmilling and dynamic instability, Structure of cilia and flagella
Motor molecules also carry vesicles or organelles to various destinations along “monorails’ provided by the cytoskeleton.
Interactions of motor proteins and the cytoskeleton circulates materials within a cell via streaming.
Recently, evidence is accumulating that the cytoskeleton may transmit mechanical signals that re-arrange the nucleoli and other structures.
Cilia and Flagella are complex filamentous cytoplasmic structures protruding through a cell wall.
They are minute, especially differentiated appendices of the cell.
Flagella wriggle like eels. They generate waves that pass along their length, usually from base to tip at constant amplitude.
Thus the movement of water by a flagellum is parallel to its axis while a cilium moves water perpendicular to its axis and, hence, perpendicular to the surface of the cell. The axoneme is connected with the basal body which is an intracellular granule lying in the cell cortex and which originates from the centrioles.
Each axoneme is filled with ciliary matrix, in which are embedded two central singlet microtubules, each with the 13 protofilaments and nine outer pairs of microtubules, called doublets. This recurring motif is known as the 9 + 2 array.
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Phyto-Pharmacological Screening, New Strategies for evaluating
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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.
A Strategic Approach: GenAI in EducationPeter 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.
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.
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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
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.
2. The cytoskeleton, which consists of a network of protein
filaments extending throughout the cytoplasm of all eukaryotic and
prokaryotic cells.
Key functions of cytoskeleton:
(1) Structure and Support (2) Intracellular Transport (3) Motility
(4) determined position of organelles (5) Involved in cell division.
3. The cytoskeleton is composed of three filamentous structures.
Microtubules,
Microfilaments,
Intermediate Filaments together form an elaborate
interactive network.
4. Microtubules:
Microtubules are rigid hollow rods approximately 25 nm in diameter.
They function both to determine cell shape and in a variety of cell
movements, the intracellular transport of organelles, and the separation of
chromosomes during mitosis.
Microtubules are components of a diverse array of structures, including
the mitotic spindle of dividing cells and in the core of cilia and flagella.
Microtubules are composed of a single type of globular protein called
tubulin.
Tubulin protein is a dimers consisting of two closely related 55 kd
polypeptides: Alpha tubulin and beta tubulin.
5. When viewed in cross section, microtubules are seen to consist of 13
proto-filaments aligned side by side in a circular pattern within the
wall.
Noncovalent interactions between adjacent protofilaments are
thought to play an important role in maintaining microtubule
structure.
6. Each protofilament is made up of β-tubulin and one α-tubulin
subunit.
The protofilament is asymmetric, with an β-tubulin at one end
and α-tubulin at the other end.
One end of a microtubule is known as the plus end and is
terminated by a row of β-tubulin subunits .
The opposite end is the minus end and is terminated by a row of
α-tubulin subunits.
7. In particular, the GTP bound to β-tubulin is hydrolyzed to GDP
during polymerization.
This GTP hydrolysis weakens the binding affinity of tubulin
for adjacent molecules, thereby favouring depolymerisation.
8. Colchicine and colcemid are examples of commonly used
experimental drugs that bind tubulin and inhibit microtubule
polymerization, which in turn blocks mitosis.
Two related drugs (vincristine, Taxol and vinblastine) are
used in cancer chemotherapy (Anticancer drugs) because they
selectively inhibit rapidly dividing cells.
9. Assembly of Microtubules:
In animal cells, most microtubules extend outward from the
centrosome.
During mitosis, microtubules similarly extend outward from
centrosomes to form the mitotic spindle, which is responsible for the
separation and distribution of chromosomes to daughter cells.
10. Microtubules also play a key role in maintaining the internal
organization of cells.
Treatment of cells with microtubule-disrupting drugs can seriously
affect the location of membranous organelles, including the ER
and Golgi complex.
11. Cilia and Flagella:
Cilia and flagella are microtubule-based projections of the plasma
membrane that are responsible for movement of a variety of
eukaryotic cells.
The microtubules are arranged in a characteristic "9 + 2" pattern.
In which a central pair of microtubules is surrounded by nine
outer microtubule doublets.
13. Structure and Organization of Microfilaments:
Microfilaments are approximately 8 nm in diameter and composed of
globular subunits of the protein actin.
Microfilaments are the smallest filaments of the cytoskeleton.
The major cytoskeletal protein of most cells is actin.
In the presence of ATP, actin monomers polymerize to form a flexible,
helical filament.
The terms actin filament, F-actin, and microfilament are basically
synonyms for this type of filament.
Consequently, the two ends of an actin filament have different structures
and dynamic properties.
14. Assembly and Disassembly of Actin Filaments:
Actin was first isolated from muscle cells, in which it constitutes
approximately 20% of total cell protein.
Actin filaments involved in muscle contraction.
Individual actin molecules are globular proteins of 375 amino acids
(43 kd).
Each actin monomer (globular [G] actin) actin monomers
polymerize to form filaments (filamentous [F] actin).
Each monomer is rotated by 166° in the filaments, which therefore
have the appearance of a double-stranded helix.
15. Actin filaments have a distinct polarity and their ends (called
barbed or plus ends, and pointed or minus ends) are
distinguishable from one another.
Each actin monomer has tight binding sites that mediate head-to-
tail interactions with two other actin monomers, so actin monomers
polymerize to form filaments.
16. Actin filaments are then able to grow by the reversible addition of
monomers to both ends, but one end (the barbed end) elongates five
to ten times faster than the pointed end.
The ATP associated with the actin monomer is hydrolyzed to ADP
at some time after it is incorporated into the growing actin filament.
17. As long as the concentration of ATP-actin monomers remains high,
subunits will continue to be added at both ends of the filament.
As filament elongation continues, the free monomer concentration
drops further.
At this point, monomers continue to be added to the only plus ends
of the filaments, but a net loss of subunits occurs at their minus
end.
This type of balance between two opposing activities is an example
of steady state.
19. Organization of Actin Filaments:
Individual actin filaments are assembled into two general types
of structures called actin bundles and actin networks in the
cell.
20. Actin filaments in bundles are cross-linked into parallel arrays by small
proteins called Cross linking protein (actin-bundling proteins).
In contrast, networks are formed by Cross linking protein (actin-
bundling proteins) that cross-link orthogonal filaments.
21. Functions of Microfilaments:
Microfilaments are also involved in intracellular motile
processes, such as the movement of vesicles, phagocytosis, and
cytokinesis.
They have roles in cell movement, muscle contraction, and cell
division.
23. Intermediate filaments have diameters between 8 and 11 nm, which
is intermediate between the diameters of the two other principal
elements of the cytoskeleton, actin filaments (about 7 nm) and
microtubules (about 25 nm).
Intermediate filaments are strong, flexible rope like fibers that
provide mechanical strength to cells.
IFs are a chemically heterogeneous group of structures that, in
humans, are encoded by approximately 70 different genes.
24. Intermediate Filament Assembly and Disassembly:
The basic building block of IF assembly is thought to be a rod like
tetramer formed by two dimers (4 polypeptides) that become
aligned side by side with their N- and C-terminal pointing in
opposite (antiparallel) directions.
Because the dimers point in opposite directions, the tetramer itself
lacks polarity.
25. • Intermediate filaments tend to be less sensitive to chemical agents
than other types of cytoskeletal elements and more difficult to
solubilize.
• Because of their insolubility, IFs were initially thought to be
permanent, unchanging structures
26. Functions of Intermediate filaments:
Unlike the microtubules and microfilaments, the intermediate
filaments have no direct involvement in cell movement.
They do however appear to support this mechanism by providing
mechanical strength to cells and tissues involved.
Vimentin and Keratin Intermediate filaments have a key role in
maintaining the position of the nucleus within cells.
They often form a ring-like network around the nucleus to hold it
in place.