This document provides an overview of cell structure and function. It begins with a brief history of cell discovery. It then defines cells and discusses the key differences between prokaryotic and eukaryotic cells. The document outlines cell theory and describes the basic components of cells, including the cell membrane, cytoplasm, organelles, and cytoskeleton. It explains the structure and functions of important organelles like the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and mitochondria. Finally, it discusses cellular processes like endocytosis, the cell cycle, and the cytoskeleton.
In this power point presentation Viewer will be able to know about the Plant Cell Constituents. How plants cells Composed with different organelles. What are the functions they have during the growth of particular plant. Plant cells are primary unit of the plant body and from here only we get medicinal value chemical constituents.
Portion Covered:
1. Plant Cells
2. Plant Cell Diagram
3. Plant cell Structure
4. Plant cell type
5. Plant cell Functions
Cell :- detailed about cell and their constituent.Sumit Tiwari
A cell is a mass of cytoplasm that is bound externally by a cell membrane. Usually microscopic in size, cells are the smallest structural units of living matter and compose all living things. Most cells have one or more nuclei and other organelles that carry out a variety of tasks
In this power point presentation Viewer will be able to know about the Plant Cell Constituents. How plants cells Composed with different organelles. What are the functions they have during the growth of particular plant. Plant cells are primary unit of the plant body and from here only we get medicinal value chemical constituents.
Portion Covered:
1. Plant Cells
2. Plant Cell Diagram
3. Plant cell Structure
4. Plant cell type
5. Plant cell Functions
Cell :- detailed about cell and their constituent.Sumit Tiwari
A cell is a mass of cytoplasm that is bound externally by a cell membrane. Usually microscopic in size, cells are the smallest structural units of living matter and compose all living things. Most cells have one or more nuclei and other organelles that carry out a variety of tasks
Crude drugs are plant, animal or their parts which after collection are subjected only to drying or making them into transverse/ longitudinal slices pieces or peeling them in some cases. They exist in natural form.
Crude drugs may be derived from various natural sources like Plants, Animals, Minerals, Marine and Micro-organisms etc
Cell is basic structural and functional unit of all living organism. Cell is enclosed in a compartment containing aqueous fluid called as Cytosol which is surrounded by a cell membrane called Plasma membrane
Introduction.
Biosynthesis
Types of Thyroid diseases
Thyroid Drugs
Antithyroid Drugs
Mechanism of action
Structure
Adverse Drug Reactions and Uses.
Reference
Pharmacognosy of Atropa belladona, biological source, geographical source, chemical constituents, uses, morphology of leaves, flower, fruits of belladona, deadly night shade leaves, chemical test, microscopy, T.S of leaves
UNIT V - Study of biological source, chemical nature and uses of drugs of
natural origin containing the following drugs
(a) Plant Products:
Fibers - Cotton,
In this ppt the students will be able to know about different inclusions of plant cells and correlate their constituents. There are different types of metabolites produce in the plant which are not useful for them but are having great medicinal property for human being.
Portion covered:
1. Cell Inclusions
2. Reserve food of plants
3. Inorganic Materials
4. Secretory Products
5. Excretory Products.
Pharmacognosy of carbohydrates containing drugs Jegan Nadar
This PPT covers Pharmacognosy of carbohydrates containing drugs. It includes Pharmacognosy of Agar, Acacia, Guar Gum, Honey ,Starch, Isapgol,Tragacanth,Sterculia Gum,Chitin and Pectin.
Pharmacognosy of Rauwolfia serpentina, biological source, geographical source, marphology of roots and rhizome, microscopy of roots, chemical constituents- reserpine, uses -antihypertensive, isolation of reserpine, serpagandha, India snake root
Crude drugs are plant, animal or their parts which after collection are subjected only to drying or making them into transverse/ longitudinal slices pieces or peeling them in some cases. They exist in natural form.
Crude drugs may be derived from various natural sources like Plants, Animals, Minerals, Marine and Micro-organisms etc
Cell is basic structural and functional unit of all living organism. Cell is enclosed in a compartment containing aqueous fluid called as Cytosol which is surrounded by a cell membrane called Plasma membrane
Introduction.
Biosynthesis
Types of Thyroid diseases
Thyroid Drugs
Antithyroid Drugs
Mechanism of action
Structure
Adverse Drug Reactions and Uses.
Reference
Pharmacognosy of Atropa belladona, biological source, geographical source, chemical constituents, uses, morphology of leaves, flower, fruits of belladona, deadly night shade leaves, chemical test, microscopy, T.S of leaves
UNIT V - Study of biological source, chemical nature and uses of drugs of
natural origin containing the following drugs
(a) Plant Products:
Fibers - Cotton,
In this ppt the students will be able to know about different inclusions of plant cells and correlate their constituents. There are different types of metabolites produce in the plant which are not useful for them but are having great medicinal property for human being.
Portion covered:
1. Cell Inclusions
2. Reserve food of plants
3. Inorganic Materials
4. Secretory Products
5. Excretory Products.
Pharmacognosy of carbohydrates containing drugs Jegan Nadar
This PPT covers Pharmacognosy of carbohydrates containing drugs. It includes Pharmacognosy of Agar, Acacia, Guar Gum, Honey ,Starch, Isapgol,Tragacanth,Sterculia Gum,Chitin and Pectin.
Pharmacognosy of Rauwolfia serpentina, biological source, geographical source, marphology of roots and rhizome, microscopy of roots, chemical constituents- reserpine, uses -antihypertensive, isolation of reserpine, serpagandha, India snake root
oral lichen planus,,preneoplastic inflammatory modelSharda university
oral lichen planus is a potentialy maligant lession,,so before any treatment planning,its important to know etiology.so i am putting my efforts in this presentation to explain several etiological factors.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
HOT NEW PRODUCT! BIG SALES FAST SHIPPING NOW FROM CHINA!! EU KU DB BK substit...GL Anaacs
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Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
NVBDCP.pptx Nation vector borne disease control program
Cell and its constituents
1. A TOUR OF THE CELL
1
Dr.Bhavna Tyagi(PG 1ST year)1
2. content
History
Defination of cell
Types and difference between prokaryotic and
eukaryotic
Cell theory
Basic aspect
Cell membrane
Cytoplasm and its organelles
Function of organelles
Cytoskeleton
Functional system of cell
2
2
3. Cell cycle
Mitosis and Meiosis
Checkpoints in cell cycle
Apoptosis
3
3
4. history
Robert Hooke used simple lenses
to observe cork in which he saw
tiny compartments he called cells
(cellulae)
4
4
6. An aggregate of cells in an organism that have
similar structure and function :Tissue
an organ (or viscus) is a collection of tissues
joined in a structural unit to serve a common function
An organism may be either unicellular (a single cell) or
comprise many trillions of cells
grouped into specialized tissues and organs.
cell 6
6
7. Types of cell
1.Prokaryotic cells :nucleus
without membrane eg .
Bacteria and Blue green algae
2.Eukaryotic cell : organised
nucleus and cell organelles eg .
Plants and animals
7
7
9. CELL THEORY
The Cell Theory
1. Schleiden (a botanist) and Schwann (a zoologist):
believed that all plants and animals consist of cells.
2. Virchow: cells come from preexisting cells.
The Cell Theory: three generalizations:
1. All organisms are composed of one or more cells.
2. The cell is the smallest unit having the properties of
life.
3. The continuity of life arises directly from the growth
and division of single cells.
9
9
10. Basic aspects
Structural Organization of Cell
All cells have three basic parts:
• 1. Plasma membrane:- separates each
cell from the environment, permits the
flow of molecules across the
membrane
10
10
11. • 2. A DNA-containing region occupies a
portion of the interior
• 3. The cytoplasm contains membrane-
bound compartments (except bacteria),
particles, and filament all bathed in a
semifluid substance
Continues…
11
11
12. Cell membrane
Biological membrane that separates
the interior of all cells from the outside
environment
Selectively permeable to ions and organic
molecules and controls the movement of
substances in and out of cells.
Protect the cell from its surroundings.
12
12
13. Thin, pliable, elastic structure only
7.5 to 10 nm thick
Composed entirely of proteins
and lipids
Appears to be trilaminar in
electron microscope.
13
13
16. CELL MEMBRANE consist of bilayer of
phospholipid molecules that are
amphipathic,i.e consist of polar head and
nonpolar tail
Polar head
(water loving)
Non polar tail
(water hating)
16
16
19. PROTEIN MOLECULES
2 types:
(a) Integral proteins:
Protrude all way through the membrane.
Provide structural channels(or pores)
through which water molecules and
water soluble substances(ions) can diffuse
between extracellular and intracellular fluid.
(b) Peripheral protiens: attached to only one
surface .
No penetration.
19
19
20. FUNCTIONS OF TRANSMEMBRANE
PROTEIN
CELL TO CELL adhesion
CELL MATRIX adhesion
Formation of pores or channels for
the transport of materials into and
out of the cell
20
20
21. GLYCOCALYX
Membrane Carbohydrates
Occur in combination with proteins
and lipids in form of glycoproteins or
glycolipids.
Entire outside surface of the cell often
has a loose carbohydrate coat called “
glycocalyx”
21
21
24. CYTOPLASM
Material enclosed by plasma
membrane.
Clear fluid portion of the cytoplasm
in which particles are dispersed is
called “cytosol”
Occupies space between plasma
membrane and nuclear membrane
24
24
25. Chemical composition of
protoplasm
Water:75 -85%
Protein :10-12%
Lipid:2-3%
Carbohydrates:1%
Inorganic substances:1%
DNA:0.4%
RNA:0.7%
25
25
26. Types of Organelles
Nonmembranous organelles:
no membrane
direct contact with cytosol
Membranous organelles:
covered with plasma membrane
isolated from cytosol
26
26
28. Non membranous organelles
Ribosomes (free ribosomes and polysomes)
Microtubules
Centrioles
Cilia and flagella
Filaments
28
28
29. THE NUCLEUS
Discovered by
Robert Hooke in
1831
Is the cell’s control
center
Contains DNA:
genetic material
29
29
30. The Nucleus contains DNA,protein called as
NUCLEOPROTEIN and some RIBONUCLEIC ACID.
2 TYPES OF NUCLEOPROTEIN
HISTONE NON HISTONE
Control the coiling and expression of the genes
encoded by DNA strands n NON PROTEIN
HISTONES
30
30
31. NUCLEI are hetrogenous
structures with
electron-dense(dark)
and electron-
lucent(light)
HETROCHROMATIN H,
consist tightly coiled
inactive chromatin found
irregular clumps
EUCHROMATIN E,
represents that part of
the DNA that is active in
RNA synthesis
31
31
32. CHROMATIN –collectively ,
HETROCHROMATIN and EUCHROMATIN
are known as CHROMATIN
CHROMATIN is a highly organised but
dynamic structure with the individual
chromosome tending to clump in
particular areas of the nucleus ,known
as chromosome territories
32
32
33. THE NUCLEOLUS
It is an accumulation of large amount of
RNA and proteins.
Nucleolus becomes considerably enlarged
when the cell is actively synthesizing
proteins.
33
33
34. MICROGRAPH OF NUCLEOLUS
F- filamentous component
G-granular component
The filamentous component
are the site for the ribosomal
RNA synthesis
RIBOSOME assembly take
place in the granular
component
34
34
35. NUCLEAR
ENVELOPE The Nuclear envelop
NE,which encloses the
nucleus N,Consist of 2
layers 0f membrane with
the
INTERMEMBRANOUS
or PERINUCLEAR
SPACE between
35
35
36. NUCLEAR PORES
The nuclear envelop contain
numerous NUCLEAR PORES (NP) at
the margins of which the inner and
outer membranes become
continuous
NUCLEAR PORES permit and
regulate the exchange of
metabolities ,macromolecules and
ribosomal subunits between the
nucleus and cytoplasm
36
36
37. Endoplasmic Reticulum
This is a complex network or reticulum of
membranes running throughout the cytoplasm
Walls are constructed of lipid bilayer membranes
that contain large amounts of proteins
Contain of flattened membrane bound sacs called
CISTERNAE
37
37
39. ROUGH ENDOPLASMIC
RETICULUM
It has ribosomes
attached throughout the
surface
This type of ER is
present in the cell which
shows active protein
synthesis
39
39
40. Micrograph shows
rER tends to b
profuse and to
form closely
packed laminae of
flattened
cisternae
NOTE the close
association
between the rER
and the outer lipid
bilayer of the
nuclear envelop
NE with which its
in continuity
40
40
42. Function of sER and eER
Active
transport
Forms
skeletal
frame work
Metabolic
activities due
to enzymes
Provide
increase
surface area
Formation of
new nuclear
membrane
during cell
division
42
42
45. GOLGI APPARATUS
Golgi apparatus is made up of one or
more golgi bodies which are stacks
of 3 – 10 flattened sacs and vesicles
Closely related to endoplasmic
reticulum
Prominent in secretory cells.
45
45
46. GOLGI
APPARATUS
Vesicles from the endoplasmic reticulum
(via the vesicular-tubular clusters) fuse with the network and
subsequently progress through the stack
to the trans Golgi network, where they are packaged and
sent to their destination. Each region contains different
enzymes which selectively modify the contents
depending on where they reside.
46
46
47. FUNCTIONS
Formation of cell wall
Synthesis of glycolipid
Lysosomes formation
Water balance
Lipid secretion
Protein secretion
47
47
48. Lysosome
membrane-bound cell organelle
They are structurally and chemically spherical
vesicles containing hydrolitic enzymes
250 to 750 nm in diameter.
Surrounded by a typical lipid bilayer
membrane.
48
48
49. Enzymes of the lysosomes are synthesised in
the rough endoplasmic reticulum.
The enzymes are released from Golgi
apparatus in small vesicles which ultimately
fuse with acidic vesicles called endosomes,
thus becoming full lysosomes
They are popularly referred to as "suicide
bags" or "suicide sacs"
of the cell
49
49
50. Types of lysosomes
Primary –these are small vesical like structure
produced from the golgi apparatus
Secondary-they are formed when phagosomes
fuse with already existing primary lysosomes
Residual bodies
Autophagic vacuoles –these lysosomes
envelope and attack intracellular organelles
like mitrochondria etc and digest them
50
50
51. FUNCTIONS
Provide an intracellular digestive system that
allows the cell to digest within itself
(a) damaged cellular structures
(b) food particles that have been
ingested .
(c) unwanted matter such as bacteria.
Autolysis of a cell by release of the enzymes
with in the cell
51
51
52. Peroxisomes
Are enzyme-containing vesicles
Break down fatty acids
Membrane sacs containing oxidases and
catalases to neutralize free radicals that are
formed during catabolism of organic molecules
Produce hydrogen peroxide (H2O2)
Peroxisomes not made by Golgi apparatus rather
formed by self-replication.
52
52
54. MITOCHONDRIA
Power house of the cell.
Present in all areas of the cell’s
cytoplasm.
Variable in size n shape
54
54
55. Two lipid bilayer protein
membrane: outer and
inner membrane.
Many infoldings of inner
layer forms shelves onto
which oxidative enzymes
are attached.
Inner cavity of
mitochondria is filled with
matrix that contains large
quantity of dissolved
enzymes that are
necessary for extracting
energy from nutrients.
55
55
57. FILAMENTS AND TUBULAR
STRUCTURES
Microfilaments
Thin filaments (<6nm diameter)
Composed of the protein actin
Usually at periphery of the cell
Functions:
provide additional strength by attaching the membrane
to the cytoplasm
Attach integral proteins to cytoskeleton
Pairs with thick filaments of myosin for muscle
movement
57
57
58. Intermediate Filaments & Thick Filaments
Intermediate Filaments:
7-11 nm diameter
Mid-sized between microfilaments and thick
filaments
Durable, type varies with cell
Functions:
• strengthen cell and maintain shape
• stabilize position of organelles
58
58
59. Thick Filaments
15 nm diameter
Composed of myosin
Muscle cells only
Function
Interact with actin to produce
movement
59
59
60. Microtubules
Large (25nm diameter), hollow tubes
Composed of tubulin protein
Originate from centrosome
60
60
61. Functions
Foundation of the cytoskeleton
Allows the cell to change shape and assists in
mobility
Involved in transport
Makes up the spindle apparatus for nuclear division
(mitosis)
The structural part of some organelles
Centrioles, cilia, flagella
61
61
62. Centrioles in the Centrosome
Centrioles : form spindle apparatus during cell
division
Centrosome: cytoplasm surrounding centriole near
the nucleus
Consists of matrix and paired centrioles
Responsible for assembling spindle apparatus
during mitosis
62
62
63. Cilia and Flagella
Hair like projections
Contain a microtubule core with cytoplasm
covered in plasma membrane
67
63
63
64. Cilia: Short, numerous
Function: sweep substances
over cell surface
Flagella: Long, singular
Function: propel cell through
environment
64
64
65. FUNCTIONAL SYSTEMS OF THE
CELL Ingestion by the cell –
ENDOCYTOSIS The plasma membrane envelops small
particles or fluid, then seals on itself to form
a vesicle or vacuole which enters the cell:
Phagocytosis
Pinocytosis
Receptor-Mediated Endocytosis
65
65
66. Phagocytosis (cell eating)
In phagocytosis, a cell engulfs a particle by
Wrapping pseudopodia around it and packaging it
within a membrane enclosed sac large enough to
be classified as a vacuole called as phagosomes
The particle is digested after the vacuole fuses
with a lysosome containing hydrolytic enzymes.
66
66
69. Mitosis and Meiosis
Cell cycle
Checkpoints in cell cycle
Apoptosis
These topic will be cover in next seminar
69
69
70. Bibliography :
wheater’s functional histology . A text
and colour Atalas . fifth edition
Arthur C. Guyton; John E. Hall. Text
book of Medical Physiology. Tenth
edition.
70
70
73. cell cycle
Proliferating cell progress
through a series of checkpoints
and defined phases called THE
CELL CYCLE
CELL CYCLE consists of
G1,S,G2,M,G0 phases
73
74. CELL CYCLE
cell growth, organelle
duplication, protein
synthesis, synthesizes
enough cytoplasm for
2 cells
DNA replication and
histone synthesis.8-12
hours after mitosis
and 7-8 hrs for
completion.
finishes protein
synthesis and centriole
replication
Mitosis involves division of
the chromosomes.
Cytokinesis involves
division of the cytoplasm.
74
75. Cell division
Multiplication of cells takes place by division of pre-existing cells.
Body (somatic) cells divide in 3 stages:
DNA replication duplicates genetic material
exactly
Mitosis divides genetic material equally
Cytokinesis divides cytoplasm and organelles
into 2 daughter cells
75
76. Mitosis
What is the purpose of mitosis?
Cell division
Products genetically identical
Growth of organism
76
77. Stages
The period during which the cell is actively
dividing is the phase of mitosis
The period between two successive
divisions is called the interphase
Interphase is often included in
discussions of mitosis, but interphase is
technically not part of mitosis, but rather
encompasses stages G1, S, and G2 of the
cell cycle.
77
79. Interphase The cell is engaged in metabolic
activity and performing its prepare
for mitosis (the next four phases that
lead up to and include nuclear
division).
Chromosomes are not clearly
discerned in the nucleus, although a
dark spot called the nucleolus may
be visible.
The cell may contain a pair of
centrioles (or microtubule
organizing centers in plants) both of
which are organizational sites for
microtubules.
79
80. prophase Chromatin in the nucleus begins to
condense and becomes visible in
the light microscope as
chromosomes.
The nucleolus disappears.
Centrioles begin moving to
opposite ends of the cell and fibers
extend from the centromeres.
Some fibers cross the cell to form
the mitotic spindle.
80
81. Prometaphase The nuclear membrane
dissolves, marking the
beginning of
prometaphase.
Proteins attach to the
centromeres creating the
kinetochores.
Microtubules attach at the
kinetochores and the
chromosomes begin
moving. 81
82. Metaphase
Spindle fibers line the chromosomes
along the middle of the cell
nucleus. This line is referred to as
the metaphase plate.
Polar microtubules extend from the
pole to the equator, and typically
overlap
Kinetochore microtubules extend
from the pole to the kinetochores
This organization helps to ensure
that in the next phase, when the
chromosomes are separated, each
new nucleus will receive one copy of
each chromosome 82
83. Anaphase The paired chromosomes
separate at the
kinetochores and move to
opposite sides of the cell.
The chromosomes are
pulled by the kinetochore
microtubules to the poles
and form a "V" shape
Motion results from a
combination of
kinetochore movement
along the spindle
microtubules and through
the physical interaction of
polar microtubules.
83
84. Telophase Chromatids arrive at
opposite poles of cell,
and new membranes
form around the
daughter nuclei.
The chromosomes
disperse and are no
longer visible under the
light microscope.
The spindle fibers
disperse, and
cytokinesis will start
84
85. Cytokinesis In animal cells,
cytokinesis results
when a fiber ring
composed of a
protein called actin
around the center of
the cell contracts
pinching the cell into
two daughter cells,
each with one
nucleus.
In plant cells,
synthesis of new cell
wall between two
daughter cells rather
than cleavage furrow
in cytoplasm
85
86. Meiosis
Function
Reduction division (23 chromosomes per gamete)
Mechanism
Each homologue (e.g. “chromosome 7”) replicates to give
two sister chromatids
Homologues pair (e.g. maternal chromosome 7 and paternal
chromosome 7)
Exchange of material between non-sister chromatids:
crossing-over, recombination
Chiasmata (visible cytologically) are the physical
manifestations of crossing-over
86
87. Meiosis
Introduction
Meiosis consist s of two successive
divisions called the first and the second
meiotic divisions
1st meiotic division
Prophase is prolonged
Divided into 4 stages
87
88. Meiosis I
Fig A represents leptotene stage-
chromosomes become visible
consist 2 chromatids ,cnt distinguish
Fig B represents zygotene stage-
pairing of chromosome called synapsis
The two chromosomes together c/a
bivalent
Fig C represents pachytene stage -4
chromatid visible c/a tetrads,2 central
and 2 peripheral chromatids.
Cont.. 88
89. Fig D cont. pachytene stage-2
central chromatid cross over c/a
crossing over
The point of crossing c/a chiasmata
Fig E represents Diplotene stage-2
chromosomes of a bivalent try to
move apart
Exchange of genetic material occur
89
91. One entire chromosome of the pair moves to
either pole
NOTE that the centromere does not divide
91
92. Similar to mitosis
NOTE that the chromosome in each cell have been reduced
to half the diploid number 92
93. 2nd mitotic division
The 1st mitotic division is
follow by the short
interphase
There is no duplication of
DNA
2nd meiotic division
similar to the mitosis
93
95. Nuclear transcription factor
Quiescent cell receive a signal to divide
MYC protein binds to DNA
Transcriptional activation of several growth
related genes including cyclin dependent
kinases
Drive cell into cell cycle MYC decline
95
96. Cyclins and Cyclins –
Dependent Kinases
Phosphoryl
ation of
RB,
molecular
on off
switch
G2/M transition initiated by
E2F mediated transcription
of cycline A,which form
complex cycA cdk2 tht
regulates mitotic prophase
Main mediator tht propel the
cell beyond prophase is cyc B-
cdk1 complex .activation of
complex leds to breakdown of
nuclear envelop n initiates
mitosis 96
98. cell cycle check points
Cell cycle has its own internal control called as
checkpoints
2 main check points ,1 at G1/M transition and another at
G2/M
S phase is point of no return ,before cell makes the final
commitment to replicate ,G1/S checkpoint checks for DNA
damage
DNA damage after its replication can still be repaired as
long as the chromatids have not separated .the G2/M
checkpoint monitor the completion of DNA replication and
checks whether the cell can safely initiates mitosis and
separates sister chromatids
98
99. G1/S checkpoint , cell cycle arrest is
mostly mediated through p53,which
induce cell cycle inhibitor p21
Arrest of cell cycle by G2/M checkpoints
involve the both p53 dependent via
cyclin A/cdk-2 and independent via cdc
25 mechanism
99
100. p53
Also called as “guardian of the genome”
Present on chromosome 17
Most mutated gene in human cancer p53 links cell
damage with DNA repair ,cell cycle arrest and
apoptosis.
P53 links cell damage with DNA repair ,cell cycle arrest
and apoptosis
In reponse to DNA damage,it is phosphorylated by
gene that sense the damage and are involved in DNA
repair
P53 assist in DNA repair by causing G1 arrest and
inducing DNA repair
A cell with DNA damaged tht cant be repaired is
directed by p53 to undergo apoptosis
100
102. APOPTOSIS
PROGRAMMED CELL DEATH
It is a pathway of cell death that is
introduced by a tightly regulated suicide
program in which cells destined to die
activate enzymes that degrade the cell’s
own nuclear DNA and nuclear and
cytoplasmic proteins.
102
103. (a) In phisiologic conditions:
Normal phenomenon that serves to eliminate cells that
are no longer needed and to maintain a steady number of
various cell populations in tissues.
examples:
During embryogenesis.
Involution of hormone-dependent tissues upon hormone
withdrawal.
Cell loss in proliferating cell populations , such as
immature lymphocytes in the bone marrow and thymus .
103
causes
104. In pathological conditions:
Eliminates cells that are injured beyond repair
without eliciting a host reaction, thus limiting
collateral tissue damage.
DNA damage: radiation anticancer drugs and
hypoxia.
Accumulation of mis folded proteins- because
of mutations in the genes encoding these
proteins or damage caused by free radicals.
Viral infections like HIV
104