ORGANISASI SEL
ORGANISASI SEL
ORGANISASI SEL
ORGANISASI SEL
Delayota Science Club (DSC)
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.
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.
L M 1 ,0 0 0 × Figure 4.1B Perkembangan Pengamatan Sel S E M 2 ,0 0 0 × T E M 2 ,8 0 0 × Figure 4.1C 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.
30 µm 10 µm
30 µm 10 µm
Surface area of one large cube
=5,400µm2
Total surface area of 27 small cubes
Macam-macam Sel
Sel prokariotik: belum memiliki organela bermembran
Sel eukariotik: memiliki organela bermembran
Prokaryotic cell Nucleoid region C o lo ri z e d T E M 1 5 ,0 0 0 × Nucleus
Eukaryotic cell Organelles
C o lo ri z e d T E M 1 5 ,0 0 0
Prokaryotic flagella
Sel Prokariotik
Umumnya berukuran lebih kecil daripada sel eukariotik Tidak memiliki membran inti (karioteka)
Ribosomes Capsule Cell wall Plasma
membrane
Nucleoid region (DNA)
Sel Eukariotik
Nucleus Smooth endoplasmic reticulum Rough endoplasmic reticulum Flagellum Ribosomes Golgi apparatus Plasma membrane Mitochondrion Not in mostplant cells Lysosome Centriole
Microtubule
Cytoskeleton Intermediatefilament
Microfilament Peroxisome
Golgi apparatus Nucleus Microtubule Ribosomes Smooth endoplasmic reticulum Rough endoplasmic reticulum
Sel Eukariotik
Central vacuole Not in animal cells Chloroplast Cell wall Cytoskeleton Intermediate filament Microfilament Mitochondrion Peroxisome Plasma membrane Sel TumbuhanStruktur Sel Eukariotik
Nukleus (inti sel)
Sitoplasma (cairan
sel)
Sistem
Organel-organel lain
Mitokondria Plastida Peroksisom GlioksisomSistem
Endomembran
Ribosom Retikulum Endoplasma Badan Golgi Lisosom Vakuola GlioksisomSitoskeleton
Mikrofilamen Mikrotubul Filamen antaraMembran 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
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
Nucleolus Nucleus 1 µm Pore complex Nuclear pore Outer membrane Inner membrane Nuclear envelope: Chromatin Rough ER
Nuclear lamina (TEM) Close-up of nuclear envelope 1 µm 0.25 µm Ribosome complex Surface of nuclear envelope
Retikulum Endoplasma (RE)
The endoplasmic reticulum
(ER) accounts for more than
half of the total membrane in many eukaryotic cells
The ER membrane is
continuous with the nuclear
Smooth ER
Rough ER
Nuclear envelope
continuous with the nuclear envelope
There are two distinct regions of ER:
Smooth ER, which lacks
ribosomes
Rough ER, with ribosomes
studding its surface
Rough ER Ribosomes Smooth ER T E M 4 5 ,0 0 0 ×
The smooth ER
Synthesizes lipids
Metabolizes carbohydrates
Detoxifies poison
Stores calcium
The rough ER
Has bound ribosomes, which secrete
Has bound ribosomes, which secrete
glycoproteins (proteins covalently bonded to
carbohydrates)
Distributes transport vesicles, proteins
surrounded by membranes
Ribosom
Ribosomes are particles
made of ribosomal RNA and protein
Ribosomes carry out
protein synthesis in two 4
Transport vesicle buds off
Large subunit Small subunit
protein synthesis in two locations:
In the cytosol (free ribosomes)
On the outside of the
endoplasmic reticulum or the nuclear envelope
(bound ribosomes) Secretory (glyco-) protein inside trans-port vesicle buds off Sugar chain 3 Rough ER Glycoprotein 2 Polypeptide Ribosome 1
Badan Golgi
The Golgi apparatus
(dictiosom) consists of flattened membranous sacs called cisternae
Functions of the Golgi
apparatus:
cis face
(“receiving” side of
Golgi apparatus) Cisternae
apparatus:
Modifies products of the ER
Manufactures certain macromolecules
Sorts and packages materials into transport vesicles
trans face
(“shipping” side of Golgi apparatus)
Lisosom
A lysosome is a
membranous sac of
hydrolytic enzymes
that can digest
macromolecules
Golgi apparatus Plasma membrane Transport vesicle (containing inactive hydrolytic enzymes) 1 Rough ERmacromolecules
Lysosomal enzymes
can hydrolyze
proteins, fats,
polysaccharides, and
nucleic acids
“Food” Food vacuole Lysosomes 2 Lysosome engulfing damaged organelle 5 Digestion 4 3 Engulfment of particleBeberapa peran lisosom:
Mencerna makanan (fagositosis), termasuk memakan bibit penyakit.
Menghancurkan organel yang tidak digunakan lagi (autofagi).
Kerusakan lisosom dapat berakibat fatal bagi
organisme tersebut.
Digestive enzymes Lysosome Plasma membrane Food vacuole (a) Phagocytosis Digestion (b) Autophagy Peroxisome Vesicle Lysosome Mitochondrion DigestionVakuola
Vakola dilingkupi oleh
membran “tonoplas”
Types of vacuole:
Food vacuoles are formed
by phagocytosis
Contractile vacuoles,
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 L M 6 5 0 × Nucleus Contractile vacuoles
Mitokondria
Mitochondria are in nearly all eukaryotic cells
They have a smooth outer membrane and an inner membrane folded into
cristae
Cristae present a large surface area for enzymes that synthesize ATP
cristae
The inner membrane
creates two compartments: intermembrane space and
mitochondrial matrix
Some metabolic steps of cellular respiration are catalyzed in the
Plastida
Plastida merupakan organela yang mempunyai fungsi
khusus.
Leukoplas: bagian plastida yang tidak berwarna, terdiri
dari:
Amiloplas: tempat menyimpan amilum Proteoplas: tempat menyimpan protein 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
Kloroplas
Merupakan bagian dari
Plastida.
Mengandung pigmen
klorofil dan enzim-enzim fotosintetik.
Berfungsi dalam proses
Struktur Kloroplas:
Berfungsi dalam proses
fotosintesis, yakni
mengubah energi cahaya menjadi energi kimia
(karbohidrat).
Dijumpai pada tumbuhan
hijau dan alga (ganggang).
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
Intermediate filaments
reinforce the cell and anchor cer tain organelles
Microtubules give the cell
rigidity and provide anchors for organelles and act as tracks Microfilaments of actin enable
cells to change shape and move.
for organelle movement
Actin subunit
Microfilament
7 nm
Fibrous subunits 10 nm
Intermediate filament Microtubule
25 nm Tubulin subunit
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.
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.
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:
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
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
0.5 µm
Intermediate filaments
Tight junction
Tight junctions prevent fluid from moving across a layer of cells
1 µm Desmosome Gap junction Extracellular matrix 0.1 µm Plasma membranes of adjacent cells Space between cells Gap junctions Desmosome filaments
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
Peripheral proteins are not embedded
Integral proteins penetrate the hydrophobic core and
often span the membrane
Integral proteins that span the membrane are called
Fibers of extracellular matrix (ECM) Glycoprotein Carbohydrate EXTRA-CELLULAR Glycolipid Microfilaments of cytoskeleton Cholesterol Integral protein Peripheral proteins CYTOPLASMIC SIDE CELLULAR SIDE
Fungsi Membran Sel
Enzymes
Signal
Receptor ATP
Transport Enzymatic activity Signal transduction
Glyco-protein
Cell-cell recognition Intercellular joining Attachment to the cytoskeleton and extra-cellular matrix (ECM)
Transport Melalui Membran
Membran sel berfungsi untuk transportasi zat-zat
keluar-masuk sel.
Transport aktif adalah transportasi zat-zat keluar
masuk membran yang membutuhkan energi, biasanya berupa ATP. Transport aktif dapat berupa:
Endositosis 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
Difusi Fasilitasi
Difusi fasilitasi merupakan proses difusi yang
“dibantu” oleh protein transport pada membran
sel, baik protein channel maupun carrier.
EXTRACELLULAR EXTRACELLULAR FLUID Channel protein Solute CYTOPLASM Carrier Protein
Osmosis
Osmosis merupakan perpindahan
molekul-molekul zat pelarut (air) dari larutan encer ke
larutan pekat melalui membran semi permeabel.
Lower concentration of solute (sugar) Higher concentration of sugar Same concentration of sugar
of solute (sugar) of sugar
of sugar
Membran semi permeabel
H2O
Proses osmosis membantu menjaga tekanan air
di dalam sel.
Animal cell
H2O H2O H2O
Hypotonic solution Isotonic solution Hypertonic solution
H2O
Lysed Normal Shriveled
H2O H2O H2O H2O Plant cell
Transport Aktif
Cytoplasmic Na+bonds to
the sodium-potassium pump
CYTOPLASM Na+ [Na+] low [K+] high Na+ Na+ EXTRACELLULAR FLUID [Na+] high [K+] low Na+ Na+ Na+ ATP ADP P Na+binding stimulates phosphorylation by ATP. Na+ Na+ Na+ Phosphorylation causes the protein to change its
P
the sodium-potassium pump phosphorylation by ATP. the protein to change its conformation, expelling Na+
to the outside.
Extracellular K+binds
to the protein, triggering release of the phosphate group.
P
P
Loss of the phosphate restores the protein’s original conformation.
K+is released and Na+
sites are receptive again; the cycle repeats.
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
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
