The endomembrane system is composed of membranes within eukaryotic cells that divide the cell into compartments. It includes the endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and vesicles. The endoplasmic reticulum is a network of membranes that synthesizes lipids and proteins. The Golgi apparatus processes and sorts proteins and other molecules for transport within the cell. Lysosomes contain digestive enzymes and break down materials through processes like autophagy and phagocytosis. Vacuoles store molecules and break down complex substances in plant cells. Together, these membrane-bound organelles work cooperatively to transport materials and carry out specialized functions within eukaryotic cells.

1. ENDOMEMBRANE SYSTEM
By-Lovnish Thakur
IBT-2ST SEM (ASU2014010100099)
COURSE-LIFE SCIENCE(BSBT201)
School of Bioscience

2. WHAT IS ENDOMEMBRANE SYSTEM
 The endomembrane system is composed of the different membranes
that are suspended in the cytoplasm within a eukaryotic cell. These
membranes divide the cell into functional and structural
compartments, or organelles.
 It consist of-:
• Endoplasmic Reticulum,
• Golgi Apparatus,
• Lysosomes,
• Vacuoles, Vesicles.

3. ENDOPLASMIC RETICULUM
IT is a network of membrane connected to nuclear
envelope & extends throughout cell.
It accounts for 50% membranes in eukaryotic cell.

5. Endoplasmic
reticulum
Smooth endoplasmic
reticulum
Does not contain
ribosome.
Rough endoplasmic
reticulum
Contain ribosome
that make it look
rough.

6. Smooth endoplasmic reticulum
Function-:
Factory processing operations like-
• many metabolic processes
• synthesis & hydrolysis
Enzymes of smooth ER help in-
• synthesize lipids, oils,
phospholipids,
• steroids & sex hormones
• hydrolysis of glycogen
• (in liver) into glucose
• detoxify drugs & poisons
(in liver)
ex. alcohol & barbiturates

7. Rough endoplasmic reticulum
Function-:
• Produce proteins for
export out of cell
• protein secreting cells
• packaged into transport
vesicles for export

8. Endoplasmic reticulum -: Membrane Factory
Synthesize membrane phospholipids
build new membrane as ER membrane expands, bud
off & transfer to other parts of cell that need
membranes
Synthesize membrane proteins

9. Golgi Apparatus
• The Golgi apparatus functions as a factory in which proteins
received from the ER are further processed and sorted for
transport to their eventual destinations: lysosomes, plasma
membrane, or secretion.
• Function
• finishes, sorts & ships cell products
• extensive in cells specialized for
Secretion

10. Structure
 flattened membranous sacs = cisternae
 2 sides = 2 functions
• Cis face receives
material by fusing
with vesicles = “receiving”
• Trans face buds off
vesicles that travel
to other sites = “shipping”
(transport)

11. Golgi processing
 During path from cis to trans, products from ER are
modified into final form tags, sorts, & packages materials
into transport vesicles
 Golgi = “UPS headquarters”
 Transport vesicles = “UPS trucks” delivering packages that
have been tagged with their own barcodes

12. Lysosomes
Structure
 membrane-bounded sac
of hydrolytic enzymes
that digests macromolecules
enzymes & membrane
of lysosomes are
synthesized by rough
ER & transferred to the
Golgi

13. Function
 A little “stomach” for the cell, lyso– = breaking things apart,
some = body. It is also called the “clean up crew” of the cell.
 In addition to degrading
molecules taken up by
endocytosis, lysosomes
digest material derived
from two other routes:
1. phagocytosis
2. autophagy

15. What if a lysomome digestive
enzyme doesn’t function?

16. Lysosomal storage diseases
 don’t digest a biomolecule instead biomolecule collects in
lysosomes
 lysosomes fill up with undigested material, lysosomes grow
larger & larger eventually disrupt cell & organ function
 “Lysosomal storage diseases”are usually fatal.
For e.g-:
Tay-Sachs disease- lipids build up
in brain cells & child dies before age 5.

17. Sometimes its supposed to work
that way…
 Apoptosis = cell death critical role in programmed destruction
of cells in multicellular organisms.
 auto-destruct mechanism-“cell suicide” some cells have to die
in an organized fashion, especially during development.
e.g-: development of space between
your fingers during embryonic
development

18. Vacuoles & vesicles
 A vacuole is a membrane-enclosed fluid filled sac found in the
cells of plants including fungi.
 Vacuoles can be large organelles occupying between 30% and 90%
of a cell by volume.

19. Vacuoles appear to have three main functions
• contribute to the rigidity of the plant using water to
develop hydrostatic pressure
• store nutrient and non-nutrient chemicals
• break down complex molecules.
Type-
 Food vacuoles- phagocytosis, fuse with lysosomes
 Contractile vacuoles- in freshwater protists, pump
excess H2O out of cell
 Central vacuoles- in many mature plant cells

20. Putting it all together…

23. REFERENCES
www.ncbi.nlm.nih.gov › NCBI › Literature › Bookshelf
bscb.org/learning-resources/softcell-e-learning/vacuole-plants
www.ncbi.nlm.nih.gov › NCBI › Literature › Bookshelf
www.ncbi.nlm.nih.gov › NCBI › Literature › Bookshelf
www.rtsd.org/cms/lib/.../The%20Cell%20Endomembrane%20Syste
m.pdf
https://fc.deltasd.bc.ca/~jonzon/S030AAF27.11/endomembrane%2
0system.pdf

24. THANK YOU