Rough ER - SMAN 8 YOGYAKARTA

ORGANISASI SEL
Delayota Science Club (DSC)
Januari 2011
Pengertian Sel
Sel ditemukan pertama kali oleh Robert Hooke
yang mengamati sayatan tanaman gabus
(Quercus suber) tahun 1665.
Theodore Schwann dan Mathias Schleiden: Sel
merupakan unit struktural terkecil penyusun
makhluk hidup.
Max Schlutze: Sel merupakan unit fungsional
terkecil penyusun makhluk hidup.
Rudolf Virchow: Setiap sel berasal dari sel lain
(omnis cellulae ex cellulae)
Walter Flemming dan Eduard Strasburger: Sel
merupakan unit reproduksi makhluk hidup.
Perkembangan
LM
1,000×
Pengamatan Sel
Figure 4.1C
TEM 2,800 ×
SEM 2,000 ×
Figure 4.1B
Figure 4.1D
Sel selalu berukuran mikroskopis (kecil) karena sel
yang berukuran kecil memiliki rasio luas
permukaan/volume yang lebih besar daripada sel
dengan ukuran yang sama.
10 µm
30 µm
30 µm
Surface area
of one large cube
= 5,400 µm2
10 µm
Total surface area
of 27 small cubes
= 16,200 µm2
Macam-macam Sel
Colorized TEM 15,000 ×
Sel prokariotik: belum memiliki organela bermembran
Sel eukariotik: memiliki organela bermembran
Prokaryotic cell
Nucleoid
region
Nucleus
Eukaryotic cell
Organelles
Sel Prokariotik
Umumnya berukuran lebih kecil daripada sel eukariotik
Tidak memiliki membran inti (karioteka)
Prokaryotic
flagella
Ribosomes
Capsule
Cell wall
Plasma
membrane
Nucleoid region (DNA)
Pili
Sel Eukariotik
Rough
endoplasmic
reticulum
Smooth endoplasmic
reticulum
Nucleus
Flagellum
Not in most
plant cells Lysosome
Ribosomes
Centriole
Peroxisome
Microtubule
Intermediate
Cytoskeleton filament
Microfilament
Golgi
apparatus
Plasma membrane
Mitochondrion
Sel Hewan
Sel Eukariotik
Nucleus
Rough
endoplasmic
reticulum
Ribosomes
Golgi
apparatus
Central
Not in vacuole
animal Chloroplast
cells
Cell wall
Smooth
endoplasmic
reticulum
Microtubule
Intermediate Cytoskeleton
filament
Microfilament
Mitochondrion
Peroxisome
Plasma membrane
Sel Tumbuhan
Struktur Sel Eukariotik
Nukleus (inti sel)
Sitoplasma (cairan
sel)
Sistem
Endomembran
Ribosom
Retikulum Endoplasma
Badan Golgi
Lisosom
Vakuola
Organel-organel lain
Mitokondria
Plastida
Peroksisom
Glioksisom
Sitoskeleton
Mikrofilamen
Mikrotubul
Filamen antara
Membran sel
Inti Sel (Nukleus)
The nucleus contains most of the cell’s genes and is
usually the most conspicuous organelle
The nuclear envelope encloses the nucleus, separating
it from the cytoplasm
The nuclear membrane is a double membrane; each
membrane consists of a lipid bilayer
In the nucleus, DNA and proteins form genetic material
called chromatin
Chromatin condenses to form discrete chromosomes
The nucleolus is located within the nucleus and is the
site of ribosomal RNA (rRNA) synthesis.
Nucleus
1 µm
Nucleolus
Chromatin
Nuclear envelope:
Inner membrane
Outer membrane
Nuclear pore
Pore
complex
Surface of
nuclear envelope
Rough ER
Ribosome
1 µm
0.25 µm
Close-up of nuclear
envelope
Pore complexes (TEM)
Nuclear lamina (TEM)
Retikulum Endoplasma (RE)
Smooth ER, which lacks
ribosomes
Rough ER, with ribosomes
studding its surface
Nuclear
envelope
Ribosomes
Rough ER
TEM 45,000×
The endoplasmic reticulum Smooth ER
(ER) accounts for more than
half of the total membrane in Rough ER
many eukaryotic cells
The ER membrane is
continuous with the nuclear
envelope
There are two distinct regions
Smooth ER
of ER:
The smooth ER
Synthesizes lipids
Metabolizes carbohydrates
Detoxifies poison
Stores calcium
The rough ER
Has bound ribosomes, which secrete
glycoproteins (proteins covalently bonded to
carbohydrates)
Distributes transport vesicles, proteins
surrounded by membranes
Is a membrane factory for the cell
Ribosom
Ribosomes are particles
made of ribosomal RNA
and protein
Ribosomes carry out
protein synthesis in two
locations:
In the cytosol (free
ribosomes)
On the outside of the
endoplasmic reticulum or
the nuclear envelope
(bound ribosomes)
Large subunit
Small subunit
Transport vesicle
buds off
4
Ribosome
3
Secretory
(glyco-) protein
inside transport vesicle
Sugar chain
1
2
Glycoprotein
Polypeptide
Rough ER
Badan Golgi
cis face
(“receiving” side of
Golgi apparatus)
Cisternae
trans face
(“shipping” side of
Golgi apparatus)
The Golgi apparatus
(dictiosom) consists of
flattened membranous
sacs called cisternae
Functions of the Golgi
apparatus:
Modifies products of the
ER
Manufactures certain
macromolecules
Sorts and packages
materials into transport
vesicles
Lisosom
Rough ER
1
A lysosome is a
membranous sac of
hydrolytic enzymes
that can digest
macromolecules
Lysosomal enzymes
can hydrolyze
proteins, fats,
polysaccharides, and
nucleic acids
Transport vesicle
(containing inactive
hydrolytic enzymes)
Golgi
apparatus
Plasma
membrane
Engulfment
of particle
Lysosome
engulfing
damaged
organelle
2
“Food”
Lysosomes
3
5
4
Food
vacuole
Digestion
Beberapa peran lisosom:
Mencerna makanan (fagositosis), termasuk memakan
bibit penyakit.
Menghancurkan organel yang tidak digunakan lagi
(autofagi).
Kerusakan lisosom dapat berakibat fatal bagi
organisme tersebut.
Lysosome
Digestive
enzymes
Lysosome
Plasma
membrane
Peroxisome
Digestion
Food vacuole
Vesicle
(a) Phagocytosis
(b) Autophagy
Mitochondrion
Digestion
Vakuola
Vakola dilingkupi oleh
membran “tonoplas”
Types of vacuole:
Nucleus
Contractile
vacuoles
LM 650×
Food vacuoles are formed
by phagocytosis
Contractile vacuoles,
found in many freshwater
protists, pump excess
water out of cells
Central vacuoles, found in
many mature plant cells,
hold organic compounds
and water
Mitokondria
Mitochondria are in nearly
all eukaryotic cells
They have a smooth outer
membrane and an inner
membrane folded into
cristae
The inner membrane
creates two compartments:
intermembrane space and
mitochondrial matrix
Some metabolic steps of
cellular respiration are
catalyzed in the
mitochondrial matrix
Cristae present a large
surface area for enzymes
that synthesize ATP
Plastida
Plastida merupakan organela yang mempunyai fungsi
khusus.
Leukoplas: bagian plastida yang tidak berwarna, terdiri
dari:
Amiloplas: tempat menyimpan amilum
Proteoplas: tempat menyimpan protein
Elaeloplas: tempat menyimpan lemak
Khromatophora: bagian plastida yang berwarna, terdiri
dari:
Khromoplas berwarna orange karena menyimpan karoten dan
xantofil
Kloroplas berwarna hijau karena menyimpan klorofil
Feoplas berwarna biru karena menyimpan fikosantin
Rhodoplas berwarna merah karena menyimpan fikoeritrin
Kloroplas
Merupakan bagian dari
Plastida.
Mengandung pigmen
klorofil dan enzim-enzim
fotosintetik.
Berfungsi dalam proses
fotosintesis, yakni
mengubah energi cahaya
menjadi energi kimia
(karbohidrat).
Dijumpai pada tumbuhan
hijau dan alga
(ganggang).
Struktur Kloroplas:
Sitoskeleton
The cytoskeleton is a network
of fibers extending throughout
the cytoplasm
It organizes the cell’s
structures and activities,
anchoring many organelles
Microfilaments of actin enable
cells to change shape and
move.
Tubulin subunit
Actin subunit
Fibrous subunits
7 nm
Microfilament
Intermediate filaments
reinforce the cell and anchor
cer tain organelles
Microtubules give the cell
rigidity and provide anchors for
organelles and act as tracks
for organelle movement
25 nm
10 nm
Intermediate filament
Microtubule
Cillia dan Flagella
Merupakan alat gerak yang dimiliki beberapa sel,
umumnya pada sel hewan.
Gerakan cillia dan flagella diatur oleh mikrotubulus
Cilia and flagella memiliki cara gerak yang berbeda.
Cara gerak flagella (bulu cambuk)
Cara gerak cillia (rambut getar)
Dinding Sel
The cell wall is an extracellular structure that
distinguishes plant cells from animal cells
The cell wall protects the plant cell, maintains its
shape, and prevents excessive uptake of water
Plant cell walls are made of cellulose fibers
embedded in other polysaccharides and protein.
Bacterial cell walls are made of peptidoglican, a
polymer from n-acetil glucosamine and n-acetil
murein.
Fungal cell walls usually are made of chitin.
Dinding sel tumbuhan mengalami penebalan
sedemikian rupa sehingga dapat dibedakan
menjadi beberapa lapisan:
Dinding primer: tersusun oleh selulosa Dinding
sekunder: tersusun oleh lignin
Lamela tengah: tersusun oleh pektin
Penebalan pada dinding sel tumbuhan dapat
terjadi dengan dua cara, yakni:
Aposisi
Intususepsi
Secondary
cell wall
Primary
cell wall
Middle
lamella
Intercellular junctions
Intercellular junctions facilitate contact between
neighbouring cells.
There are several types of intercellular junctions.
Plasmodesmata: channels that perforate plant cell walls
Tight junctions: membranes of neighboring cells are
pressed together, preventing leakage of extracellular
fluid
Desmosomes: (anchoring junctions) fasten cells
together into strong sheets
Gap junctions: (communicating junctions) provide
cytoplasmic channels between adjacent cells
Tight junction
Tight junctions prevent
fluid from moving
across a layer of cells
0.5 µm
Tight junction
Intermediate
filaments
Desmosome
Gap
junctions
Space
between
cells
Plasma membranes
of adjacent cells
Desmosome
1 µm
Extracellular
matrix
Gap junction
0.1 µm
Membran Sel
A membrane is a collage of different proteins
embedded in the fluid matrix of the lipid bilayer
Proteins determine most of the membrane’s specific
functions
Peripheral proteins are not embedded
Integral proteins penetrate the hydrophobic core and
often span the membrane
Integral proteins that span the membrane are called
transmembrane proteins
Fibers of
extracellular
matrix (ECM)
Glycoprotein
Carbohydrate
Glycolipid
EXTRACELLULAR
SIDE
Cholesterol
Microfilaments
of cytoskeleton
Peripheral
proteins
Integral
protein
CYTOPLASMIC
SIDE
Fungsi Membran Sel
Signal
Enzymes
Receptor
ATP
Transport
Enzymatic activity
Signal transduction
Glycoprotein
Cell-cell recognition
Intercellular joining
Attachment to the
cytoskeleton and extracellular matrix (ECM)
Transport Melalui Membran
Membran sel berfungsi untuk transportasi zat-zat keluarmasuk sel.
Transport aktif adalah transportasi zat-zat keluar
masuk membran yang membutuhkan energi, biasanya
berupa ATP. Transport aktif dapat berupa:
Endositosis
Eksositosis
Pompa Na/K
Transport pasif adalah transportasi zat-zat keluar
masuk membran yang tridak membutuhkan energi.
Transport pasif dapat berupa:
Difusi
Difusi terfasilitasi
Osmosis
Difusi
Difusi merupakan perpindahan molekul-molekul zat
terlarut dari larutan yang pekat (hipertonis) ke larutan
yang lebih encer (hipotonis) gradien konsentrasi.
Molecules of dye
Membrane (cross section)
WATER
Net diffusion
Net diffusion
Equilibrium
Difusi Fasilitasi
Difusi fasilitasi merupakan proses difusi yang
“dibantu” oleh protein transport pada membran
sel, baik protein channel maupun carrier.
EXTRACELLULAR
FLUID
Channel protein
Carrier Protein
Solute
CYTOPLASM
Osmosis
Osmosis merupakan perpindahan molekulmolekul zat pelarut (air) dari larutan encer ke
larutan pekat melalui membran semi permeabel.
Lower
concentration
of solute (sugar)
Higher
concentration
of sugar
H2O
Osmosis
Membran semi permeabel
Same concentration
of sugar
Proses osmosis membantu menjaga tekanan air
di dalam sel.
Hypotonic solution
Isotonic solution
Hypertonic solution
Animal
cell
H2O
H2O
Turgid (normal)
H2O
H2O
Flaccid
H2O
Shriveled
Normal
Lysed
Plant
cell
H2O
H2O
H2O
Plasmolyzed
Transport Aktif
EXTRACELLULAR [Na+] high
FLUID
[K+] low
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
CYTOPLASM
[Na+] low
[K+] high
Na+
Cytoplasmic Na+ bonds to
the sodium-potassium pump
P
Extracellular K+ binds
to the protein, triggering
release of the phosphate
group.
ATP
P
ADP
P
Na+ binding stimulates
phosphorylation by ATP.
Phosphorylation causes
the protein to change its
conformation, expelling Na+
to the outside.
Loss of the phosphate
restores the protein’s
original conformation.
K+ is released and Na+
sites are receptive again;
the cycle repeats.
P
Eksositosis dan Endositosis
Exocytosis: transport vesicles migrate to the
membrane, fuse with it, and release their contents.
Endocytosis: the cell takes in macromolecules by
forming vesicles from the plasma membrane.
Endocytosis is a reversal of exocytosis, involving
different proteins
• Three types of endocytosis:
Phagocytosis (“cellular eating”): Cell engulfs particle
in a vacuole
Pinocytosis (“cellular drinking”): Cell creates vesicle
around fluid
Receptor-mediated endocytosis: Binding of ligands to
receptors triggers vesicle formation