Transcript Endoplasmic Reticulum

Endoplasmic Reticulum, Golgi
Complex, Lysosome, Peroxisome
Asmarinah
Depart of Medical Biology, Faculty of Medicine
University of Indonesia
The structure of cells
a
b
Schematic diagrams of
a. “generalized” bacterial cell
b. Plant cell
c
c. Animal cell
Intracellular compartment of eucaryotic cell
Example: Epithelial cell lines the male reproductive tract
Each organelle of
the eucaryotic cell
Contains :
- characteristic set of
enzyme
- specialized molecules
- distribution systems
of transport
The composition of eukaryotic cell:
- Membrane system
-Cytoplasm/cytosol
-Organelles : Nucleus
Endoplasmic reticulum (ER)
Golgi apparatus
Mitochondria, in plants: chloroplast
Lysosome
Peroxisome
-Cytoskeleton
Endoplasmic Reticulum
-Constitutes more than half of total membrane of an
average animal cell
-Is organized into a netlike labyrinth of branching
tubules and flattened sacs extending throughout the
cytosol
ER network in mammalian cell
ER is divided into two subcompartment:
a. the rough endoplasmic reticulum (RER)
has ribosomes bound to its cytosolic surface
RER is the starting point of the biosynthetic pathway:
the site of synthesis protein, carbohydrate chains and
phospholipids
b. the smooth endoplasmic reticulum (SER)
lacks assosiated ribosomes
-extensively developed in a number of the cell types
-Function, i.e:
* Synthesis of steroids hormones
* Detoxifications in the liver of a wide variety of
organic compounds
Ribosome
• play role in protein biosynthesis
• has no cell membrane
• are small granule (25 nm) that can produce more than
40% of protein (70 kinds of proteins) and 60 % RNA.
• found abundant in the surface of ER, but also found in
mitochondria as well as in chloroplast
• Ribosome are produced in nucleolus.
• Each type of cell has different amount of ribosome
Example: E. Coli has 1,500 ribosome.
Polyribosomes
Golgi complex
-has characteristic morphology consisting primary of
flattened, disliked and membranous cisternae
- Receives lipids and protein
from ER and dispatches them
to a variety of destination
-is divided into several
function distinct
compartment, from the cis or
entry face closest to the ER,
to the trans or exit face at
the opposite end
The cis face composed of an interconnected network,
refers as, cis Golgi Network (CGN). The function is as a
sorting station that distinguishes between protein to be
shipped back to the ER and those that are allowed to
proceed to the next Golgi station
The trans face containing a distinct network of tubules and
vesicles, called trans Golgi Network (TGN), is sorting
station for diifferent types of vesicle heading either to
plasma membrane or to various intracellular destinations
Lysosome
-is an animal cell’s digestive
organelles
-Contains approximately 50
different hydrolytic enzymes
produced in the ERE and
targeted to these organelles
-Enzymes have their optimal
activity at an acid pH (= acid
hydrolase), and can hydrolize
every type of macro
molecules
Lysosome range in size,
from large size (over 1
um) to very small (25-50
nm in diameter)
Three pathways to degradation in lysosome
Peroxisome (microbody)
- found in all eukaryotic cell
- The site of synthesis and degradation of hydrogen
peroxide (H2O2), a highly reactive and toxic oxiding
agents
-Is mayor site of oxigen
utilization, like
mitochondria
- Contains
oxidatives
enzymes, such as catalase
and urate oxidase
References
Alberts et al., 2002. Molecular Biology of the Cell.
4 ed.
Karp G. 2005. Cell and Molecular Biology. 4 ed.
Thanks you