This document discusses cell organelles and plasma membrane. It describes that cells contain various organized structures called organelles, which can be separated by disrupting the cell membrane and applying differential centrifugal forces. Some organelles contain marker enzymes that can identify them. The document then discusses the structure and functions of the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria, and plasma membrane. It explains that the plasma membrane regulates transport into and out of the cell using both passive and active transport mechanisms.
Cell Anatomy and physiology ( structure and function for NEET asparients, Biology, MBBS, BPT, Allied, nursing , medical and paramedical students. This is the easiest form of slide share to understand the context better.
Animal cells are typical of the eukaryotic cell, enclosed by a plasma membrane and containing a membrane-bound nucleus and organelles. Unlike the eukaryotic cells of plants and fungi, animal cells do not have a cell wall. This feature was lost in the distant past by the single-celled organisms that gave rise to the kingdom Animalia. Most cells, both animal and plant, range in size between 1 and 100 micrometers and are thus visible only with the aid of a microscope.
All living organisms are made of cells and cellular products. The cell is the smallest structural, functional, and biological unit of all living organisms. It can capable of biosynthesis, replication and energy transformation. All cellular organelles carry out specific functions that are necessary for the normal functioning of the cell. Animal cells work together and function interdependently. Human cells vary in size, shape, and function. Most animal cells are so small they can only be seen with the aid of a microscope. Based on function, there are more than 200 different kinds of animal cells that help each system contribute to the homeostasis of the entire body. Despite their many differences, human cells have several similar structural features: a cell membrane, a nucleus, and cytoplasm and cell organelles.
Cell Anatomy and physiology ( structure and function for NEET asparients, Biology, MBBS, BPT, Allied, nursing , medical and paramedical students. This is the easiest form of slide share to understand the context better.
Animal cells are typical of the eukaryotic cell, enclosed by a plasma membrane and containing a membrane-bound nucleus and organelles. Unlike the eukaryotic cells of plants and fungi, animal cells do not have a cell wall. This feature was lost in the distant past by the single-celled organisms that gave rise to the kingdom Animalia. Most cells, both animal and plant, range in size between 1 and 100 micrometers and are thus visible only with the aid of a microscope.
All living organisms are made of cells and cellular products. The cell is the smallest structural, functional, and biological unit of all living organisms. It can capable of biosynthesis, replication and energy transformation. All cellular organelles carry out specific functions that are necessary for the normal functioning of the cell. Animal cells work together and function interdependently. Human cells vary in size, shape, and function. Most animal cells are so small they can only be seen with the aid of a microscope. Based on function, there are more than 200 different kinds of animal cells that help each system contribute to the homeostasis of the entire body. Despite their many differences, human cells have several similar structural features: a cell membrane, a nucleus, and cytoplasm and cell organelles.
eukaryote, any cell or organism that possesses a clearly defined nucleus. The eukaryotic cell has a nuclear membrane that surrounds the nucleus, in which the well-defined chromosomes (bodies containing the hereditary material) are located.
Cell :Structure & Functions for Medical and Health allied StudentsRajendra Dev Bhatt
The cell is the basic structural and functional unit of all known living organisms.
It is the smallest unit of life that is classified as a living thing, and is often called the building block of life.
• The membrane enclosing a cell is called cell membrane or plasma membrane (animal cells) and plasma lemma (plant cells).
• It contains proteins and lipids in the ratio of 80 : 20 in bacteria on one extreme and on the other extreme 20 : 80 in some nerve cells.
• The over all composition of most of the cell membranes is 40-50% protein and 50-60% lipids; both the components vary in their composition.
Cell Structures and Functions In pathology.pptxVictory120660
Cell structure and function are fundamental to understanding biology. Here's a broad overview:
1. **Cell Structure:**
- **Cell Membrane:** Acts as a barrier, controlling the passage of substances in and out of the cell.
- **Cytoplasm:** Gel-like substance within the cell where organelles are suspended.
- **Nucleus:** Contains genetic material (DNA) and controls cell activities.
- **Organelles:** Structures within the cell with specific functions, such as mitochondria (energy production), endoplasmic reticulum (protein synthesis), Golgi apparatus (protein packaging), and lysosomes (digestion).
2. **Cell Function:**
- **Metabolism:** Cells carry out metabolic processes to maintain life, including energy production, nutrient breakdown, and waste removal.
- **Reproduction:** Cells can reproduce through processes like mitosis (cell division) or meiosis (reproductive cell division).
- **Homeostasis:** Cells maintain a stable internal environment by regulating processes like temperature, pH, and nutrient levels.
- **Communication:** Cells communicate with each other through chemical signals, allowing coordination within tissues and organ systems.
- **Differentiation:** Cells specialize into different types with specific functions during development, forming tissues and organs.
- **Response to Stimuli:** Cells can respond to external stimuli, such as light or chemicals, through processes like movement or changes in gene expression.
Understanding cell structure and function is crucial for comprehending biological processes at all levels, from the functioning of individual organisms to the interactions within ecosystems.
eukaryote, any cell or organism that possesses a clearly defined nucleus. The eukaryotic cell has a nuclear membrane that surrounds the nucleus, in which the well-defined chromosomes (bodies containing the hereditary material) are located.
Cell :Structure & Functions for Medical and Health allied StudentsRajendra Dev Bhatt
The cell is the basic structural and functional unit of all known living organisms.
It is the smallest unit of life that is classified as a living thing, and is often called the building block of life.
• The membrane enclosing a cell is called cell membrane or plasma membrane (animal cells) and plasma lemma (plant cells).
• It contains proteins and lipids in the ratio of 80 : 20 in bacteria on one extreme and on the other extreme 20 : 80 in some nerve cells.
• The over all composition of most of the cell membranes is 40-50% protein and 50-60% lipids; both the components vary in their composition.
Cell Structures and Functions In pathology.pptxVictory120660
Cell structure and function are fundamental to understanding biology. Here's a broad overview:
1. **Cell Structure:**
- **Cell Membrane:** Acts as a barrier, controlling the passage of substances in and out of the cell.
- **Cytoplasm:** Gel-like substance within the cell where organelles are suspended.
- **Nucleus:** Contains genetic material (DNA) and controls cell activities.
- **Organelles:** Structures within the cell with specific functions, such as mitochondria (energy production), endoplasmic reticulum (protein synthesis), Golgi apparatus (protein packaging), and lysosomes (digestion).
2. **Cell Function:**
- **Metabolism:** Cells carry out metabolic processes to maintain life, including energy production, nutrient breakdown, and waste removal.
- **Reproduction:** Cells can reproduce through processes like mitosis (cell division) or meiosis (reproductive cell division).
- **Homeostasis:** Cells maintain a stable internal environment by regulating processes like temperature, pH, and nutrient levels.
- **Communication:** Cells communicate with each other through chemical signals, allowing coordination within tissues and organ systems.
- **Differentiation:** Cells specialize into different types with specific functions during development, forming tissues and organs.
- **Response to Stimuli:** Cells can respond to external stimuli, such as light or chemicals, through processes like movement or changes in gene expression.
Understanding cell structure and function is crucial for comprehending biological processes at all levels, from the functioning of individual organisms to the interactions within ecosystems.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
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.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
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.
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.
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.
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.
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Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
3. • Cells contain various organized structures, collectively called as cell
organelles.
• When the cell membrane is disrupted, either by mechanical means or
by lysing the membrane by Tween-20 (a lipid solvent) the organized
particles inside the cell are homogenized.
• This is usually carried out in 0.25M sucrose at pH 7.4.
• The organelles could then be separated by applying differential
centrifugal forces.
• Albert Claude got Nobel prize in 1974 for fractionating subcellular
organelles
4. • Some enzymes are present in
certain organelles only, such
specific enzymes are called as
marker enzymes.
• After centrifugation, the
separated organelles are
identified by detection of marker
enzymes in the sample.
5. Discuss about the following cell organelles
1) Nucleus
2) Endoplasmic reticulum
3) Golgi apparatus
4) Lysosomes
5) peroxisome
6) Mitochondria
7) Plasma membrane
6. 1) NUCLEUS
• It is the most prominent organelle of the cell. All cells in the body
contain nucleus, except mature RBCs in circulation. The uppermost
layer of skin also may not possess a readily identifiable nucleus. In
some cells, nucleus occupies most of the available space, e.g. small
lymphocytes and spermatozoa.
• Nucleus is surrounded by two membranes—the inner one is called
perinuclear membrane with numerous pores and the outer
membrane is continuous with membrane of endoplasmic reticulum.
• Nucleus contains the DNA, the chemical basis of genes, which
governs all the functions of the cell. The very long DNA molecules are
complexed with proteins to form chromatin and are further organized
into chromosomes..
7. DNA replication and RNA synthesis (transcription) are taking place
inside the nucleus
In some cells, a portion of the nucleus may be seen as lighter shaded
area nucleolus.This is the area for RNA processing and ribosome
synthesis. The nucleolus is very prominent in cells actively
synthesizing proteins.
Vesicular transport across membrane is by endocytosis and
exocytosis. Importin and exportin proteins are involved, and it is
helped by RanGAP proteins.
8. 2) ENDOPLASMIC RETICULUM
It is a network of interconnecting membranes enclosing channels or
cisternae, that are continuous from outer nuclear envelope to outer
plasma membrane.
Under electron microscope, the reticular arrangements will have railway
track appearance.
This will be very prominent in cells actively synthesizing proteins
e.g. immunoglobulin secreting plasma cells.
The proteins, glycoproteins and lipoproteins are synthesised in the ER.
Detoxification of various drugs is an important function of ER. Microsomal
cytochrome P-450 hydroxylates drugs, such as benzpyrine, aminopyrine,
aniline, morphine, phenobarbitone, etc.
9. • ER is generally classified into rough and smooth. The rough
appearance is due to ribosomes attached to cytoplasmic side of
membrane where the proteins are being synthesized.
• When cells are fractionated, the complex ER is disrupted in many
places. They are automatically reassembled to form microsomes.
• ERGIC (Endoplasmic reticulum - Golgi intermediate compartment):
The synthesized protein pass through this compartment before going
to the cis Golgi.
10.
11. 3) GOLGI APPARATUS
The Golgi organelle is a
network of flattened smooth
membranes and vesicles. It may
be considered as the converging
area of endoplasmic reticulum
While moving through ER,
carbohydrate groups are
successively added to the
nascent proteins. These
glycoproteins reach the Golgi
area.
12. Golgi apparatus is composed of cis, medial and trans cisternae.
Glycoproteins are generally transported from ER to cis Golgi (proximal
cisterna) then to medial Golgi (intermediate cisterna) and finally to trans
Golgi (distal cisterna) for temporary storage. Trans Golgi is particularly
abundant with vesicles containing glycoproteins.
Newly synthesized proteins are sorted first according to the sorting
signals available in the proteins.
Then they are packaged into transport vesicles having different types
of coat proteins. Finally they are transported into various destinations.
Main function of Golgi apparatus is protein sorting, packaging and
secretion
13. 4) LYSOSOMES
• Lysosomes are tiny organelles
• They are bags of enzymes.
• Endocytic vesicles and phagosomes are fused with lysosome (primary) to form the
secondary lysosome or digestive vacuole.
• Foreign particles are progressively digested inside these vacuoles. Completely hydrolyzed
products are utilized by the cell. As long as the lysosomal membrane is intact, the
encapsulated enzymes can act only locally.
• But when the membrane is disrupted, the released enzymes can hydrolyze external
substrates, leading to tissue damage.
• The lysosomal enzymes have an optimum pH around 5.
• Polysaccharide hydrolyzing enzymes (alpha-glucosidase, alpha-fucosidase, beta-
galactosidase, alpha-mannosidase, betaglucuronidase, hyaluronidase, aryl sulfatase,
lysozyme)
• Protein hydrolyzing enzymes (cathepsins, collagenase, elastase, peptidases)
• Nucleic acid hydrolyzing enzymes (ribonuclease, deoxyribonuclease)
• Lipid hydrolyzing enzymes (fatty acyl esterase, phospholipases)..
14. 5) PEROXISOMES
• The peroxisomes have a granular matrix.
• They are of 0.3–1.5 mm in diameter.
• They contain peroxidases and catalase. They are prominent in
leukocytes and platelets.
• Peroxidation of polyunsaturated fatty acids in vivo may lead to
hydroperoxide formation.
• The free radicals damage molecules, cell membranes, tissues and
genes.
• Catalase and peroxidase are the enzymes present in peroxisomes,
which will destroy the unwanted peroxides and other free radicals
15. 6) MITOCHONDRIA
• They are spherical, oval or rod-like bodies, about 0.5–1 mm in diameter and up to
7 mm in length.
• Erythrocytes do not contain mitochondria. The tail of spermatozoa is fully packed
with mitochondria.
• Mitochondria are the powerhouse of the cell, where energy released from
oxidation of food stuffs is trapped as chemical energy in the form of ATP.
• Mitochondria have two membranes. The inner membrane convolutes into folds
or cristae. The inner mitochondrial membrane contains the enzymes of electron
transport chain. The fluid matrix contains the enzymes of citric acid cycle, urea
cycle and heme synthesis.
• Cytochrome P-450 system present in mitochondrial inner membrane is involved
in steroidogenesis.
• Superoxide dismutase is present in cytosol and mitochondria.
16.
17. • Mitochondria also contain specific DNA. The integral inner
membrane proteins, are made by mitochondrial protein synthesizing
machinery. However, the majority of proteins, especially of outer
membrane are synthesized under the control of cellular DNA. The
division of mitochondria is under the command of mitochondrial
DNA.
• Mitochondrial ribosomes are different from cellular ribosomes.
• Antibiotics inhibiting bacterial protein synthesis do not affect cellular
processes, but do inhibit mitochondrial protein biosynthesis.
• Mitochondria play a role in triggering apoptosis
• Mitochondria are continuously undergoing fission and fusion,
resulting in mixing of contents of mitochondrial particles. Specific
fission and fusion proteins have been identified and abnormalities in
some of these proteins are implicated in diseases like CharcotMarie-
Tooth disease
18.
19. 7) PLASMA MEMBRANE
• The plasma membrane separates the cell from the external environment.
• It has highly selective permeability properties so that the entry and exit of
compounds are regulated. The cellular metabolism is in turn influenced
and probably regulated by the membrane. The membrane is metabolically
very active.
• Membranes are mainly made up of lipids, proteins and small amount of
carbohydrates. The contents of these compounds vary according to the
nature of the membrane. The carbohydrates are present as glycoproteins
and glycolipids.
• Phospholipids are the most common lipids present and they are
amphipathic in nature. Cell membranes also contain cholesterol.
20. Fluid mosaic model
• structure of the biomembranes was described as a fluid mosaic model by
Singer and Nicolson, 1972.
• The phospholipids are arranged in bilayers with the polar head groups oriented
towards the extracellular side and the cytoplasmic side with a hydrophobic core.
• The distribution of the phospholipids is such that choline containing
phospholipids are mainly in the external layer and ethanolamine and serine
containing phospholipids in the inner layer.
• Each leaflet is 25 Å thick, with the head portion 10 Å and tail 15 Å thick. The total
thickness is about 50 to 80 Å. C.
• The lipid bilayer shows free lateral movement of its components, hence the
membrane is said to be fluid in nature. Fluidity enables the membrane to perform
endocytosis and exocytosis.
• components do not freely move from inner to outer layer, or outer to inner layer
(flip-flop movement is restricted). During apoptosis (programed cell death), flip-
flop movement occurs.
21.
22. • The cholesterol content of the membrane alters the fluidity of the
membrane.
• When cholesterol concentration increases, the membrane becomes less
fluid on the outer surface, but more fluid in the hydrophobic core. The
effect of cholesterol on membrane fluidity is different at different
temperatures.
• The nature of the fatty acids also affects the fluidity of the membrane,
the more unsaturated cis fatty acids increase the fluidity.
• The fluidity of the membrane is maintained by the length of the
hydrocarbon chain, degree of unsaturation and nature of the polar head
groups.
• Trans fatty acids (TFA) decrease the fluidity of membranes due to close
packing of hydrocarbon chains.
23. MEMBRANE PROTEINS :
The peripheral proteins exist on the surfaces of the bilayer.
They are attached by ionic and polar bonds to polar heads of the lipids.
Anchoring of proteins to lipid bilayers.
Several peripheral membrane proteins are tethered to the membranes by
covalent linkage with the membrane lipids. Since the lipids are inserted
into the hydrophobic core, the proteins are firmly anchored.
The integral membrane proteins are deeply embedded in the bilayer and
are attached by hydrophobic bonds or van der Waals forces.
Some of the integral membrane proteins span the whole bilayer and they
are called transmembrane proteins .
The hydrophobic side chains of the amino acids are embedded in the
hydrophobic central core of the membrane.
The transmembrane proteins can serve as receptors (for hormones,
growth factors, neurotransmitters), tissue specific antigens, ion channels,
membrane-based enzymes.
25. TRANSPORT MECHANISM
• The permeability of substances across cell membrane is dependent
on their solubility in lipids and not on their molecular size..
• Water soluble compounds are generally impermeable and require
carrier mediated transport.
• An important function of membrane is to withhold unwanted
molecules while permitting entry of molecules necessary for cellular
metabolism.
26. Classified into two types :
1) Passive transport
2) Active transport
3) pumps
Facilitated diffusion
Ion channels
Simple diffusion
27. Simple diffusion :
occurs from higher to lower concentration.
does not require any energy.
it is a slow process
facilitated diffusion :
carrier mediated process.
no energy required
rate of transport is more rapid than simple diffusion
ping and pong states( two conformations)
eg: glucose transporters
28. Ion channels :
are specilaised carrier systems.
allow passage of molecules in accordance with the concentration
gradient.
eg : ligand gated channels- acetyl choline receptor
calcium channels.
Active transport :
requires energy.
unidirectional
requires specialised integral protein- transporters
saturated at higher concentration of solutes.
susceptible to inhibition by specifiv organic or inorganic
compounds.