fungsi organel 091

FUNGSI ORGANEL SELFUNGSI ORGANEL SELFUNGSI ORGANEL SELFUNGSI ORGANEL SEL• Pentingnya Sel Pentingnya Sel • Semua organisma tersusun oleh sel Semua organisma tersusun oleh sel • Sel adalah kumpulan dari materi yang Sel adalah kumpulan dari materi yang

paling sederhana yang dapat hiduppaling sederhana yang dapat hidup

• Sel Eukaryotik• Mempunyai membran internal yang luas,

membentuk organel• Setiap organel mempunyai fungsi yang

spesifik• contoh

– Sel hewan– Sel tanaman

• A animal cell

Rough ER Smooth ER

Centrosome

CYTOSKELETON

Microfilaments

Microtubules

Microvilli

Peroxisome

Lysosome

Golgi apparatus

Ribosomes

In animal cells but not plant cells:LysosomesCentriolesFlagella (in some plant sperm)

Nucleolus

Chromatin

NUCLEUS

Flagelium

Intermediate filaments

ENDOPLASMIC RETICULUM (ER)

Mitochondrion

Nuclear envelope

Plasma membrane

Figure 6.9

• A plant cell

In plant cells but not animal cells:ChloroplastsCentral vacuole and tonoplastCell wallPlasmodesmata

CYTOSKELETON

Ribosomes (small brwon dots)

Central vacuole

Microfilaments

Intermediate filaments

Microtubules

Rough endoplasmic reticulum Smooth

endoplasmic reticulum

ChromatinNUCLEUS

Nuclear envelope

Nucleolus

Chloroplast

PlasmodesmataWall of adjacent cell

Cell wall

Golgi apparatus

Peroxisome

Tonoplast

Centrosome

Plasma membrane

Mitochondrion

Figure 6.9

Nucleus:

• Inti merupakan “Genetic Library of the Cell”

• Sel Eukaryotic mempunyai suatu inti yang berisi gen selular dalam wujud chromatin.

• Chromatin adalah suatu adalah kompleks DNA dan protein.

• Selama mitosis chromatin membentuk chromosomes.

• Inti di bungkus oleh membran yang memisahkan dengan sitoplasma

Figure 6.10

Nucleus

NucleusNucleolus

Chromatin

Nuclear envelope:Inner membrane

Outer membrane

Nuclear pore

Rough ER

Porecomplex

Surface of nuclear envelope.

Pore complexes (TEM). Nuclear lamina (TEM).

Close-up of nuclearenvelope

Ribosome

1 µm

1 µm

0.25 µm

Ribosomes

• Ribosomes• Merupakan pabrik Protein di dalam sel• Ribosomes terdiri atas RNA dan protein

dan mempunyai fungsi akan manyatukan polypeptides dari amino subunit asam.

– Carry out protein synthesis

ER

Endoplasmic reticulum (ER)

Ribosomes Cytosol

Free ribosomes

Bound ribosomes

Largesubunit

Smallsubunit

TEM showing ER and ribosomes Diagram of a ribosome

0.5 µm

Figure 6.11

Endoplasmic Reticulum (ER)

• Merupakan “Biosynthetic Factory”• Endoplasmic reticulum adalah suatu

sistem membran di dalam sel yang terlibat di dalam berbagai proses seperti sintese protein dan pengangkutan, metabolisme lemak dan sintesa steroid.

• ER dibedakan menjadi 2 bagian:

• Smooth ER • Rough ER Smooth ER

Rough ER

ER lumen

Cisternae

RibosomesTransport vesicle

Smooth ER

Transitional ER

Rough ER 200 µm

Nuclearenvelope

Figure 6.12

Fungsi Smooth ER

• Synthesizes lipids• Metabolizes carbohydrates• Stores calcium• Detoxifies poison

Fungsi Rough ER

• Has bound ribosomes• Produces proteins and membranes,

which are distributed by transport vesicles

• Menerima bahan yang dihasilkan oleh rough ER• Memodifikasi bahan yang dihasilkan oleh rough ER • Merupakan pabrik makromolekul tertentu• Apparatus Golgi adalah bagian dari sistem

membran di dalam sel • Apparatus Golgi memodifikasi protein dan

membawa mereka ke permukaan sel untuk dapat dikeluarkan.

• Yang dikeluarkan meliputi hormon, enzim, antibodi dan molekul lain.

Apparatus Golgi

Golgiapparatus

TEM of Golgi apparatus

cis face(“receiving” side ofGolgi apparatus)

Vesicles movefrom ER to Golgi Vesicles also

transport certainproteins back to ER

Vesicles coalesce toform new cis Golgi cisternae

Cisternalmaturation:Golgi cisternaemove in a cis-to-transdirection

Vesicles form andleave Golgi, carryingspecific proteins toother locations or tothe plasma mem-brane for secretion

Vesicles transport specificproteins backward to newerGolgi cisternae

Cisternae

trans face(“shipping” side ofGolgi apparatus)

0.1 0 µm16

5

2

3

4

• Functions of the Golgi apparatus

Figure 6.13

Lysosomes

• Lysosomes dibungkus oleh membran yang berfungsi dalam membantu mencerna molekul, dan mereka bisa lakukan ini oleh karena bagian dalam yang asam berisi enzim pencernaan.

• Mereka juga membuat gula, asam amino, dan merupakan basis yang dapat membantu menciptakan awalan dari seluruh makromolekul yang mereka cerna.

• Lysosomes carry out intracellular digestion by– Phagocytosis

Figure 6.14 A(a) Phagocytosis: lysosome digesting food

1 µm

Lysosome containsactive hydrolyticenzymes

Food vacuole fuses with lysosome

Hydrolyticenzymes digestfood particles

Digestion

Food vacuole

Plasma membrane

Lysosome

Digestiveenzymes

Lysosome

Nucleus

• Autophagy

Figure 6.14 B(b) Autophagy: lysosome breaking down damaged organelle

Lysosome containingtwo damaged organelles 1 µ m

Mitochondrionfragment

Peroxisomefragment

Lysosome fuses withvesicle containingdamaged organelle

Hydrolytic enzymesdigest organellecomponents

Vesicle containingdamaged mitochondrion

Digestion

Lysosome

Vacuoles

• Pada sel tanaman atau fungi

• Food vacuoles– Dibentuk dari hasil phagocytosis

• Contractile vacuoles– Dengan cara memompa air keluar sel protista

• Central vacuoles– Are found in plant cells– Hold reserves of important organic

compounds and water

Central vacuole

Cytosol

Tonoplast

Centralvacuole

Nucleus

Cell wall

Chloroplast

5 µmFigure 6.15

• Mitochondria and chloroplasts change energy from one form to another

• Mitochondria– Are the sites of cellular respiration

• Chloroplasts– Found only in plants, are the sites of

photosynthesis

Mitochondria

• Mitochondria, merupakan organel yang lain di dalam sel eukaryotic, sering dikenal sebagai " pembangkit listrik" dari sel itu.

• Di sini, makanan yang kita makan diubah ke dalam bahan bakar atau energi untuk sel dan badan kita.

• Mitochondria mempunyai DNA mereka sendiri

Mitochondria: Chemical Energy Conversion

• Mitochondria– Are found in nearly all eukaryotic cells

• Mitochondria are enclosed by two membranes– A smooth outer membrane– An inner membrane folded into cristae

Mitochondrion

Intermembrane space

Outermembrane

Freeribosomesin the mitochondrialmatrix

MitochondrialDNA

Innermembrane

Cristae

Matrix

100 µm

Chloroplasts

• Chloroplasts, seperti mitochondria,• Fotosintesis terjadi di dalam

chloroplasts memanfaatkan produk disandikan di dalam CHLOROPLAST

• Chloroplast juga mempunyai ribosomes sendiri

Chloroplasts: Capture of Light Energy

• The chloroplast– Is a specialized member of a family of closely related

plant organelles called plastids– Contains chlorophyll

• Chloroplasts– Are found in leaves and other green organs of plants and

in algae

Chloroplast

ChloroplastDNA

RibosomesStroma

Inner and outermembranes

Thylakoid

1 µm

Granum

• Chloroplast structure includes– Thylakoids, membranous sacs– Stroma, the internal fluid

Membran sel• Membran sel binatang

adalah sangat penting di dalam itu melindungi organelles dan juga menjaga partikel yang tak dikehendaki memasuki badan sel.

• Terbuat dari phospholipid bilayer yang mempunyai protein mengapung di dalamnya.

• Protein merupakan membran yang melapisi permukaan dalam dan luar dari sel

Peroxisomes: Oxidation

• Peroxisomes– Produce hydrogen peroxide and convert it to water

ChloroplastPeroxisome

Mitochondrion

1 µm

Figure 6.19

The cytoskeleton is a network of fibers that organizes structures and activities in the cell

• The cytoskeleton– Is a network of fibers extending throughout the

cytoplasm

Figure 6.20

Microtubule

0.25 µm MicrofilamentsFigure 6.20

Roles of the Cytoskeleton: Support, Motility, and

Regulation

• The cytoskeleton– Gives mechanical support to the cell

– Is involved in cell motility, which utilizes motor proteins

VesicleATP

Receptor formotor protein

Motor protein(ATP powered)

Microtubuleof cytoskeleton

(a) Motor proteins that attach to receptors on organelles can “walk”the organelles along microtubules or, in some cases, microfilaments.

Microtubule Vesicles 0.25 µm

(b) Vesicles containing neurotransmitters migrate to the tips of nerve cell axons via the mechanism in (a). In this SEM of a squid giant axon, two  vesicles can be seen moving along a microtubule. (A separate part of the experiment provided the evidence that they were in fact moving.)Figure 6.21 A, B

Components of the Cytoskeleton

• There are three main types of fibers that make up the cytoskeleton

Table 6.1

Microtubules• Microtubules

– Shape the cell– Guide movement of organelles– Help separate the chromosome

copies in dividing cells

Centrosomes and Centrioles

• The centrosome– Is considered to be a “microtubule-

organizing center”

– Contains a pair of centrioles

Centrosome

Microtubule

Centrioles

0.25 µm

Longitudinal sectionof one centriole

Microtubules Cross sectionof the other centrioleFigure 6.22

Cilia and Flagella

• Cilia and flagella– Contain specialized arrangements of

microtubules– Are locomotor appendages of some

cells

Microfilaments (Actin Filaments)• Microfilaments

– Are built from molecules of the protein actin– Are found in microvilli

0.25 µm

Microvillus

Plasma membrane

Microfilaments (actinfilaments)

Intermediate filaments

Figure 6.26

• Microfilaments that function in cellular motility– Contain the protein myosin in addition to actin

Actin filament

Myosin filament

Myosin motors in muscle cell contraction. (a)

Muscle cell

Myosin arm

Figure 6.27 A

Intermediate Filaments

• Intermediate filaments– Support cell shape– Fix organelles in place

Cell Walls of Plants

• The cell wall– Is an extracellular structure of plant cells

that distinguishes them from animal cells

• Plant cell walls– Are made of cellulose fibers embedded in other

polysaccharides and protein– May have multiple layers

Central vacuoleof cell

PlasmamembraneSecondarycell wallPrimarycell wall

Middlelamella

1 µm

Centralvacuoleof cell

Central vacuole CytosolPlasma membrane

Plant cell walls

PlasmodesmataFigure 6.28

The Extracellular Matrix (ECM) of Animal Cells

• Animal cells– Lack cell walls– Are covered by an elaborate matrix, the ECM

• The ECM– Is made up of glycoproteins and other macromolecules

Collagen

Fibronectin

Plasmamembrane

EXTRACELLULAR FLUID

Micro-filaments

CYTOPLASM

Integrins

Polysaccharidemolecule

Carbo-hydrates

Proteoglycanmolecule

Coreprotein

Integrin

Figure 6.29

A proteoglycan complex

• Functions of the ECM include– Support– Adhesion– Movement– Regulation