1st Yr, 1, Cell Structure

8/6/2019 1st Yr, 1, Cell Structure

1/31

1


2/31

Introduction,Review of Cell morphology,

and Cytoskeleton,

Compiled by:

Dr Muhammad Ashraf

06.07.20102


3/31

General Pathology:Pathologic conditions that are commonly

seen in most diseases and organs. 3

Pathology: Study of disease, especially structuraland functionalchanges caused by human disease.

Four aspects of disease process studied in pathology are:

Etiology: The cause of disease (Gr. aitia, cause)

(intrinsic (genetic) or external (environmental))

Pathogenesis: The mechanism &stages of disease

developm

ent.Morphology: Gross and microscopic study of structural

alterations produced by disease in the tissues andcells of the body. (Footprints of disease in tissues)

Clinical features: Corelation between structural changes

with alteration in functions of body.


4/31


5/31

Small

molecule

Relativesizesofcellsandtheircomponents

Virus BacteriumSmall

molecule

Animal

cellPlant

cell

1 mm = 1000 m

1 m = 1000 nm

1 nm = 10 A

1 m = 100 cm (102 )

1 m = 1000 mm (103 )

1 m = 1000,000 m (106 )

1 m = 1000,000,000 nm (109 )

1 m = 1000,000,000,0 A (1010) 5


6/31

Animal Cellwith

organelles

6


7/31


8/31

ADP combine with PitoformATP inacontinuouscycle

8


9/31

Mitochondrionis a cell organelle of ovoid shape

that is the majorsourceforintracellularenergy.

Mitochondria can migrate

through the cytoplasm and

change their shape. These

organelles have an outerunit

membrane and an innermembrane. The latter has

cristae, crest-like protrusions,

into the matrix

(mitochondrial plasma).

Mitochondrial half-life is thought

to be about 5-12 days.

9


10/31

Plasma Membrane

Lipid-GlobularproteinmosaicModel

Plasma membrane is a structure enveloping a cell,

enclosing the cytoplasm and forming a selective

permeability barrier. It consists of lipids, proteins and

some carbohydrates, the lipids thought to form a

bilayer in which integral proteins are embedded to a

varying degrees,

Lipidbilayer

10


11/31

GranularEndoplasmicReticulumRibonucleoprotein

particles (Ribosomes)

Flattened Cisterna of E.R.

TubularE.R.

Vesicles of E.R.

Rough endoplasmic reticulum, Golgi complex

andlysosomes are functionally and

structurally related to one another and the

plasma membrane. Membranbound transport vesicles shuttle back and

forth with materials. Proteins are synthesized

in ribosomes and reach the Golgi complex.

Finally the proteins reach the trans Golgi

network (TGN) at the end of stack and sorted

out to their final destination.11


12/31

The endoplasmic reticulum is a series

of interconnected, intracytoplasmic,

membrane bounded sacs.

The "rough" appearance of the rough

endoplasmic reticulum (RER

) resultsfrom the presence of ribosomes that

are bound to the cytosolic side of the

endoplasmic reticulum membrane.

The presence of ribosomes on the

RER indicates that it is involved in

Protein synthesis.

The smooth endoplasmic reticulum (SER)

has no such bound ribosomes and is notinvolved in protein synthesis.

However, the SER is involved in cholesterol

metabolism, membrane synthesis,

detoxification, Ca++ storage along with other

cellular processes.

EndoplasmicReticulum

Ribosomes Membrane

12


13/31

Golgi Complex

Transport vesicles

Secretory

granules

Golgi

cisternae

Camillo Golgi, 1843-1926. Italianneurologist and histologist; won

Nobel prize for physiology in 1906 forstructure of the nervous system.

The Golgi Complexfunctions as

a processing plant,modifying the

membranecomponents and cargo

synthesized in theendoplasmic reticulumbefore it moves on tothe target destination.

The materials enterthe stack at the cis

face and move byvesicle transport

towards the oppositeor trans face

13


14/31


15/31

Proteins and lipids built in the smooth and roughendoplasmic reticulum bud off in tiny bubble-like vesicles

that move through the cytoplasm until they reach the Golgicomplex.

The vesicles fuse with the Golgi membranes and releasetheir internally stored molecules into the organelle.

Once inside, the compounds are further processed by the

Golgi apparatus, which adds molecules or chops tiny piecesoff the ends.

When completed, the product is extruded fromthe GA ina vesicle and directed to its final destination inside or

outside the cell.

The exported products are secretions of proteins orglycoproteins that are part of the cell's function in the

organism.

Other products are returned to the endoplasmic reticulum ormay undergo maturation to become lysosomes

15


16/31

The Rough ER manufactures

membranes and secretoryproteins. In leukocytes the

rough ER produces antibodies.

In pancreatic cells the rough

ER produces insulin.

The rough and smooth ER are

usually interconnected and the

proteins and membranes made

by the rough ER move into the

smooth ER to be transferred toother locations.

16


17/31

1. Nuclear membrane2. Nuclear pore

3. Rough endoplasmic

reticulum (REM)

4. Smooth endoplasmic

reticulum

5. Ribosome attached to REM

6. Macromolecules7. Transport vesicles

8. Golgi apparatus

9. Cis face of Golgi apparatus

10. Trans face of Golgi

apparatus

11. Cisternae of Golgi apparatus

12. Secretory vesicle13. Cell membrane

14. Fused secretory vesicle

releasing contents

15. Cell cytoplasm

16. Extracellular environment

Secretorypathwaydiagram,includingnucleus,endoplasmicreticulumandGolgiapparatus.

10. Trans

face

9.

Cis

face

17


18/31

All animals have skeletons tokeep up their shape and

forms and get help for

locomotion.

What about the animal cells?How they keep up their shape

and form and how they move

about?

18


19/31

The cytoskeleton (also CSK) is a cellular

scaffolding" or skeleton" contained within

the cytoplasm.

The cytoskeleton is present in all cells; It is a dynamic

structure that maintains cellshape, often protects the cell,

enables cellular motion (using structures such as

flagella and cilia), and

plays important roles in both intracellulartransport(the movementofvesicles and

organelles),

and cellulardivision.(W)19


20/31

20

Microfilaments

8 nm diameter: Double helical polymers

of the protein Actin.

Microtubules

Intermediate Filaments

24 nm diameter. Wall is a polymer of

globular protein subunit - tubulin

Mitotic spindle, core of cilia and flagella

10 nm diameter, intermediate between

microtubules & microfilaments

Help in cell motility

Solid, smooth surfaced, unbranched


21/31


22/31

RoleofCytoskeleton

inPhagocytosis

22


23/31

RoleofCytoskeletonin Phagocytosis

23


24/31


25/31

Endothelialcellsunderthemicroscope.Nuclei are stained blue

with DAPI, microtubules

are marked green by anantibody bound to FITC

and actin filaments are

labeled red with phalloidin

bound to TRITC.DAPI or 4',6-diamidino-2-phenylindole isa fluorescent stain that binds strongly to DNA.It is used extensively in Fluorescencemicroscopy. Since DAPI will pass through anintact cell membrane, it may be used to stainboth live and fixed cellsFITC Fluorescein isothiocyanate; used as afluorescent label for proteins, especially antibodies.

TRITC Tetramethyl Rhodamine Iso-Thiocyanate

Phalloidin is one of a group of toxinsfrom the death cap (Amanita phalloides)

known as phallotoxins. It binds actin,

preventing its depolymerization and

poisoning the cell.

Bovinepulmonaryarteryendothelialcells

25


26/31

Cytoskeleton:anetworkofproteinfibersinthecytoplasmthatgivesshapetoacell,holdsand

movesorganelles,andistypicallyinvolvedincell

movement.

Cytoskeleton of

a cultured

epithelialcell.

Microtubules

are shown in

green, actin isshown in red

and DNA in the

nucleus is in

blue.

26


27/31

Crosssectionthrough Spermaxoneme

Electronmicrograph

27


28/31

StructureofSpermaxoneme,Diagramatic

Nexin

bridge

28


29/31

29

Asimplifieddepictionofanaxonemalcross-section.


30/31

30

3D StructureofAxoneme


31/31

Date post:	08-Apr-2018
Category:	Documents
Upload:	zaibunnisa
View:	217 times
Download:	0 times

1st Yr, 1, Cell Structure

Documents