Cell junctions can be classified into three main types - occluding junctions, communicating junctions, and anchoring junctions. Occluding junctions prevent molecules from passing between cells, like tight junctions. Communicating junctions allow exchange of substances between cells, like gap junctions. Anchoring junctions provide structural attachment between cells or cells and the extracellular matrix, like desmosomes. Cell adhesion molecules are important proteins that promote cell-cell and cell-matrix interactions and are involved in processes like embryonic development, wound healing, and intracellular signaling. Major families of cell adhesion molecules include cadherins, selectins, integrins, and the immunoglobulin superfamily.
The Golgi apparatus, also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells.
It is of particular importance in processing proteins for secretion, containing a set of glycosylation enzymes that attach various sugar monomers to proteins as the proteins move through the apparatus.
here u will find every detail of golgi.
Structure and functon of golgi apparatusICHHA PURAK
The Power point presentation consists of 77 slides including following heads
Introduction
Discovery
Distribution
Origin
Shape
Chemical composition
Structure
Common functions
Cell specific functions
Proteoglycans are assembled in G A
Lpid metabolism in G A
Protein sorting
Vesicular Tubular Clusters (VTCs)
Only properly folded and assembled protein can leave ER
Proteins leave ER in COPII coated transport vesicles
summary
questions
References
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Cell is the smallest structural and functional unit in the body of living
organism and micro-organism. Cell has a Cell membrane in its outer most
part in case of animals and cell wall for plant and for plants, cell membrane
is present under the cell wall. Cell membrane has a scientific structure. So,
many scientists gives description about the structure of cell membrane like
Sandwich Model, Unit Membrane model and Fluid Mosaic Model. But,
the Fluid Mosaic Model is widely acceptable.
Exocytosis is the process of moving materials from within a cell to the exterior of the cell. This process requires energy and is therefore a type of active transport. Exocytosis is an important process of plant and animal cells as it performs the opposite function of endocytosis. In endocytosis, substances that are external to a cell are brought into the cell.
In exocytosis, membrane-bound vesicles containing cellular molecules are transported to the cell membrane. The vesicles fuse with the cell membrane and expel their contents to the exterior of the cell. The process of exocytosis can be summarized in a few steps.
Vesicles containing molecules are transported from within the cell to the cell membrane.
The vesicle membrane attaches to the cell membrane.
Fusion of the vesicle membrane with the cell membrane releases the vesicle contents outside the cell.
There are three common pathways of exocytosis. One pathway, constitutive exocytosis, involves the regular secretion of molecules. This action is performed by all cells. Constitutive exocytosis functions to deliver membrane proteins and lipids to the cell's surface and to expel substances to the cell's exterior.
Regulated exocytosis relies on the presence of extracellular signals for the expulsion of materials within vesicles. Regulated exocytosis occurs commonly in secretory cells and not in all cell types. Secretory cells store products such as hormones, neurotransmitters, and digestive enzymes that are released only when triggered by extracellular signals. Secretory vesicles are not incorporated into the cell membrane but fuse only long enough to release their contents. Once the delivery has been made, the vesicles reform and return to the cytoplasm.
A third pathway for exocytosis in cells involves the fusion of vesicles with lysosomes. These organelles contain acid hydrolase enzymes that break down waste materials, microbes, and cellular debris. Lysosomes carry their digested material to the cell membrane where they fuse with the membrane and release their contents into the extracellular matrix.
Cell, in biology, the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed. A single cell is often a complete organism in itself, such as a bacterium or yeast. Other cells acquire specialized functions as they mature. These cells cooperate with other specialized cells and become the building blocks of large multicellular organisms, such as humans and other animals. Although cells are much larger than atoms, they are still very small. The smallest known cells are a group of tiny bacteria called mycoplasmas; some of these single-celled organisms are spheres as small as 0.2 μm in diameter (1μm = about 0.000039 inch), with a total mass of 10−14 gram—equal to that of 8,000,000,000 hydrogen atoms. Cells of humans typically have a mass 400,000 times larger than the mass of a single mycoplasma bacterium, but even human cells are only about 20 μm across. It would require a sheet of about 10,000 human cells to cover the head of a pin, and each human organism is composed of more than 30,000,000,000,000 cells.
similarities and differences between cells
similarities and differences between cells
Basic similarities between cells and ways cells may vary depending on their function.
See all videos for this article
This article discusses the cell both as an individual unit and as a contributing part of a larger organism. As an individual unit, the cell is capable of metabolizing its own nutrients, synthesizing many types of molecules, providing its own energy, and replicating itself in order to produce succeeding generations. It can be viewed as an enclosed vessel, within which innumerable chemical reactions take place simultaneously. These reactions are under very precise control so that they contribute to the life and procreation of the cell. In a multicellular organism, cells become specialized to perform different functions through the process of differentiation. In order to do this, each cell keeps in constant communication with its neighbours. As it receives nutrients from and expels wastes into its surroundings, it adheres to and cooperates with other cells. Cooperative assemblies of similar cells form tissues, and a cooperation between tissues in turn forms organs, which carry out the functions necessary to sustain the life of an organism.
The Golgi apparatus, also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells.
It is of particular importance in processing proteins for secretion, containing a set of glycosylation enzymes that attach various sugar monomers to proteins as the proteins move through the apparatus.
here u will find every detail of golgi.
Structure and functon of golgi apparatusICHHA PURAK
The Power point presentation consists of 77 slides including following heads
Introduction
Discovery
Distribution
Origin
Shape
Chemical composition
Structure
Common functions
Cell specific functions
Proteoglycans are assembled in G A
Lpid metabolism in G A
Protein sorting
Vesicular Tubular Clusters (VTCs)
Only properly folded and assembled protein can leave ER
Proteins leave ER in COPII coated transport vesicles
summary
questions
References
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Cell is the smallest structural and functional unit in the body of living
organism and micro-organism. Cell has a Cell membrane in its outer most
part in case of animals and cell wall for plant and for plants, cell membrane
is present under the cell wall. Cell membrane has a scientific structure. So,
many scientists gives description about the structure of cell membrane like
Sandwich Model, Unit Membrane model and Fluid Mosaic Model. But,
the Fluid Mosaic Model is widely acceptable.
Exocytosis is the process of moving materials from within a cell to the exterior of the cell. This process requires energy and is therefore a type of active transport. Exocytosis is an important process of plant and animal cells as it performs the opposite function of endocytosis. In endocytosis, substances that are external to a cell are brought into the cell.
In exocytosis, membrane-bound vesicles containing cellular molecules are transported to the cell membrane. The vesicles fuse with the cell membrane and expel their contents to the exterior of the cell. The process of exocytosis can be summarized in a few steps.
Vesicles containing molecules are transported from within the cell to the cell membrane.
The vesicle membrane attaches to the cell membrane.
Fusion of the vesicle membrane with the cell membrane releases the vesicle contents outside the cell.
There are three common pathways of exocytosis. One pathway, constitutive exocytosis, involves the regular secretion of molecules. This action is performed by all cells. Constitutive exocytosis functions to deliver membrane proteins and lipids to the cell's surface and to expel substances to the cell's exterior.
Regulated exocytosis relies on the presence of extracellular signals for the expulsion of materials within vesicles. Regulated exocytosis occurs commonly in secretory cells and not in all cell types. Secretory cells store products such as hormones, neurotransmitters, and digestive enzymes that are released only when triggered by extracellular signals. Secretory vesicles are not incorporated into the cell membrane but fuse only long enough to release their contents. Once the delivery has been made, the vesicles reform and return to the cytoplasm.
A third pathway for exocytosis in cells involves the fusion of vesicles with lysosomes. These organelles contain acid hydrolase enzymes that break down waste materials, microbes, and cellular debris. Lysosomes carry their digested material to the cell membrane where they fuse with the membrane and release their contents into the extracellular matrix.
Cell, in biology, the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed. A single cell is often a complete organism in itself, such as a bacterium or yeast. Other cells acquire specialized functions as they mature. These cells cooperate with other specialized cells and become the building blocks of large multicellular organisms, such as humans and other animals. Although cells are much larger than atoms, they are still very small. The smallest known cells are a group of tiny bacteria called mycoplasmas; some of these single-celled organisms are spheres as small as 0.2 μm in diameter (1μm = about 0.000039 inch), with a total mass of 10−14 gram—equal to that of 8,000,000,000 hydrogen atoms. Cells of humans typically have a mass 400,000 times larger than the mass of a single mycoplasma bacterium, but even human cells are only about 20 μm across. It would require a sheet of about 10,000 human cells to cover the head of a pin, and each human organism is composed of more than 30,000,000,000,000 cells.
similarities and differences between cells
similarities and differences between cells
Basic similarities between cells and ways cells may vary depending on their function.
See all videos for this article
This article discusses the cell both as an individual unit and as a contributing part of a larger organism. As an individual unit, the cell is capable of metabolizing its own nutrients, synthesizing many types of molecules, providing its own energy, and replicating itself in order to produce succeeding generations. It can be viewed as an enclosed vessel, within which innumerable chemical reactions take place simultaneously. These reactions are under very precise control so that they contribute to the life and procreation of the cell. In a multicellular organism, cells become specialized to perform different functions through the process of differentiation. In order to do this, each cell keeps in constant communication with its neighbours. As it receives nutrients from and expels wastes into its surroundings, it adheres to and cooperates with other cells. Cooperative assemblies of similar cells form tissues, and a cooperation between tissues in turn forms organs, which carry out the functions necessary to sustain the life of an organism.
This presentation intends to explore the communication of the cell within and others for sustainability along the regulation mechanisms by the cellular neural networks and others to sing the song of the life.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
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.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
2. Definition and Classification of cell junction
Cell junction is the connection between the neighbouring cells
or the contact between the cell and extracellular matrix.
It is also called membrane junction.
Cell junction are classified into three types
a-Occluding junction
b-Communicating junction
c-Anchoring junction.
3. Cell Adhesion Molecules (CAMs)
Important cell surface proteins molecules promoting
cell–cell and cell–matrix interactions.
Important for many normal biological processes -
embryonic cell migration, immune system functions,
wound healing.
Involved in intracellular signaling pathways (primarily
for cell death/survival, secretion etc.)
4. Cell Adhesion Molecules (CAMs)
Express 3 major domains:
The extracellular domain allows one CAM to bind to
another on an adjacent cell.
The transmembrane domain links the CAM to the
plasma membrane through hydrophobic forces.
The cytoplasmic domain is directly connected to the
cytoskeleton by linker proteins.
5. Cell Adhesion Molecules (CAMs)
Interactions between CAMs can be mediated by :
Binding of an adhesion
molecule on one cell to
the same adhesion
molecule on a second
cell
Cadherin - cadherin
An adhesion molecule
on one cell type binds
to a different type of
cell adhesion molecule
on a second cell
Selectins – mucins
The linker molecule in
most cases is Laminin,
a family of large cross
shaped molecules with
multiple receptor
domains.
6. These cell adhesion molecules can be divided into 4
major families
The cadherin superfamily
The selectins
The immunoglobulin superfamily and
The integrins
7. The Cadherin superfamily
Cadherins are the most prevalent CAMs in
vertebrates.
125 kD transmembrane glycoproteins - mediate
intercellular adhesion in epithelial and endothelial
cells by Ca2+ dependent homophilic adhesion.
Primarily link epithelial and muscle cells to their
neighbors
Form desmosomes and adherens junctions
Play critical role during development (cell sorting).
Do not interact with extracellular matrix.
8. The Cadherin superfamily
Contain a short transmembrane domain
and a relatively long extracellular
domain containing four cadherin
repeats (EC1-EC4), each of which
contains calcium binding sequences
Cadherins interact with specific
cytoplasmic proteins, e.g., catenins (α, β
and γ), as a means of being linked to the
actin cytoskeleton.
The binding of cadherins to the
catenins is crucial for cadherin
function.
9. The Selectins
Structural features of selectins
include:
NH2-terminal C-type Ca2+
dependent lectin like binding
domain, which determines the
ability of each selectin to bind to
specific carbohydrate lingands.
an epidermal growth factor-like
region.
a number of repeat sequences.
a membrane-spanning region
and
a short cytoplasmic region
10. Immunoglobulin Superfamily
Molecules
Consists of more than 25 molecules.
Important ones being:
Intracellular adhesion molecule 1(ICAM1; CD54)
Intercellular adhesion molecule 2 (ICAM2),
Vascular cell adhesion molecule1 (VCAM1; CD106),
Platelet endothelial cell adhesion molecule 1 (PECAM 1;
CD31) and
the mucosal addressin cell adhesion molecule 1
(MAdCAM1).
11. The integrins
Fifteen different α and eight different β
subunits give rise to over twenty
different heterodimeric combinations
at cell surfaces.
Bind epithelial and muscle cells to
laminin in the basal lamina
Allow platelets to stick to exposed
collagen in a damaged blood vessel
Allow fibroblasts and white blood cells
to adhere to fibronectin and collagen as
they move
13. Occluding Junction
A cell-cell junction that seals cells together in an epithelium in a way that
prevents even small molecules from leaking from one side of the sheet to
the other.
Tight Junction
Tight Junction- occluding junctions / zonulae occludens - zonula
occludens), are the closely associated areas of two cells whose
membranes join together forming a virtually impermeable barrier to fluid.
A type of junctional complex present only in vertebrates.
Consist of linear array of several integral proteins.
Junctional proteins occludins and claudins & members of IG suprfamily
are transmembrane proteins.
14. Function of Tight Junction
Strength and stability
Selective permeable for ions.
Fencing function
Maintance of cell polarity
Blood-brain barrier
Cludin -16 in Thick Junctions of Ascending Loop of
henle.
Cludin- 15 Permability of cations / anions.
15. Adhering Junctions
Desmosome- Connects intermediate filament of one
cell with other cells.
Claudin
Hemidesmosome
Desmoplakin is essential for normal desmosomal
adhesion.
16. Communicating Junction
Cell junction which permit the
intercellular exchange of substance are
called communicating junction, these
junction permit the movement of ions and
molecules from one cell to another cell.
a- Gap junction
b- Chemical synapse
17. Gap Junction
Gap junctions are clusters of intercellular channels
that allow direct diffusion of ions and small molecules
between adjacent cells.
At gap junctions, the intercellular space narrows from
25 nm to 3 nm.
gap junctions were first discovered in myocardium and
nerve because of their properties of electrical
transmission between adjacent cells (Weidmann 1952;
Furshpan and Potter 1957).
18. • Low resistance intercellular junction that allows
passage of ions and smaller molecules between the
cells.
It present in heart, basal part of epithelial cell of
intestinal mucosa, etc
Junctional unit-Connexons- 6 connexins
Connexon of one cell have allignment with connexon
of other cells.
19. Gap Junction
Electron microscopy of gap junctions joining adjacent hepatocytes in
the mouse. The gap junction (GJ) is seen as an area of close plasma
membrane apposition
20. Function of gap junction-
channel passage the substance have molecular
weight less than 1000.
Exchange of chemical messenger between cells
Rapid propagation of action potential from one cell
to another cell.
21. Desmosomes
Also known as macula adherens is a cell structure specialized
for cell-to-cell adhesion.
Are molecular complexes of cell adhesion proteins and
linking proteins that attach the cell surface adhesion proteins
to intracellular keratin cytoskeletal filaments.
The cell adhesion proteins of the desmosome, desmoglein
and desmocollin, are members of the cadherin family.
On the cytoplasmic side of the plasma membrane, there are
two dense structures called the Outer Dense Plaque (ODP)
and the Inner Dense Plaque (IDP).
The Outer Dense Plaque is where the cytoplasmic domains of the
cadherins attach to desmoplakin via plakoglobin and plakophillin.
The Inner Dense Plaque is where desmoplakin attaches to the
intermediate filaments of the cell.
23. Hemidesmosomes
Hemidesmosomes look like half-desmosomes that
attach cells to the underlying basal lamina.
Rather than using desmogleins, hemidesmosomes use
desmopenetrin cell adhesion proteins,which are
members of Integrin family.
The integrin molecule attach to one of many multi-
adhesive proteins such as laminin, resident within the
extracellular matrix, thereby forming one of many
potential adhesions between cell and matrix.
24. Chemical synapse
Chemical synapse is the junction between a nerve fibre and a
muscle fiber or between two nerve fibre ,through which signals
transmitted by the release of chemical transmitter.
25.
26.
27. Anchoring junction.
Anchoring junction are the junction ,which provides strength to
the cell by acting like mechanical attachment.
These junction provide firm structural attachment between two
cells or between a cell and extracellular matrix
Anchoring junction are responsible for structural integrity of
the tissue.
28. various cell junctions found in a vertebrate epithelial cell, classified
according to their primary functions
29.
30.
31. MCQs
Q1-which of the following is a cell adhesion
molecule
a-integrin
b-lysin
c-myosin
d-keratin
32. Q2-desmosomes differ from tight junction because
a-allow molecules to pass in the intercellular
space
b-are non-communicating
c-are present in plants
d-lack proteins
33. Q3-the Cell Junctions allowing exchange of
cytoplasmic molecules between two cells are called:
a. Gap Junctions
b. Tight Junctions
c. Anchoring Junctions
d. Focal Junctions
34. Q.4- Desmosome has the following
characters except:
a- is a disk like attachment between cells
b- is located only between epithelial cells
c- is specialized for adhesion
d-is called macula adherns
35. Q.5- Gap junctions
a- permit the passage of large proteins from cell
to cell
b- form part of the classical junctional complex
c- exist only between epithelial cells
d- are areas of low resistance for nerve
stimulation
36. Q-6 Which of the following apply to intercellular junctions?
a) The three major adhesive junctions of animal cells are
adherens junctions, desmosomes and hemidesmosomes.
b) Desmosomes and hemidesmosomes connect epithelial
cells to their basement membrane and adjacent cells
respectively.
c) Gap junctions and plasmodesmata are homologous
structures.
d) The junctional complexes of gastrointestinal
enterocytes ensure that nutrients are only absorbed
through the spaces between the cells, which prevents them
absorbing potentially harmful substances.
ANS-a
37. Q-7 tight junction
a-are essential for metabolic coupling
b-dont occur in vertebrates
c-have the closest approach of two plasma
membranes of any junction
d-surround connexions
38. Q-8 hemi desmosome differs from spot desmosome
because hemi desmosome
a-connect cell to cell
b-connect extracellular matrix to extracellular matrix
c-connect cell to extracellular matrix
d-having tonofilament ,made up of intermediate
filament