SEL: Teori, Struktur, Organela
drg. Amandia Dewi Permana Shita, M.Biomed
Cell Theory • 1600’s- the invention of the microscope, in 1665 • An Englishman Robert Hooke first observed cork cells and he reported to the world that life’s smallest structural units were “little boxes” or “cells”
Cell Theory 1675. The Dutch amateur scientist Anton van Lieuwenhoek first : – Observed living cells in pond water, rainwater and in material scraped from his teeth. – He drew the basic form of bacteria as coccus, rods and spiral
Diatoms
Paramecium
Cell Theory 1838: German botanist Schleiden: ONION CELLS
concluded that all plants are made of cells. Schleiden
Cell Theory 1839. German biologist Theodor Schwann stated that all animals are made of cells. A. Gut B. brain C. bone marrow F. kidney
d. cartilage
e. muscle
Cell Theory Cell is the smallest unit of life. Every living thing is made up of one or more cells. Human Liver Cells
•Humans have an estimated 100 trillion cells. •The largest known cell is an unfertilized egg cell Human skin cell
Cell Theory • Until the second half of the 19th century many scientists and philosophers believed that some form of life could arise spontaneously from nonliving matter spontaneous generation. • 1855. German physician Rudolf Virchow concluded that all cells come from existing cells (omnis cellula ex cellula) The Theory of Biogenesis
Mitosis: Cell Division
Cell Theory Cells are the basic unit of structure and function in living things In 1953 Watson and Crick made their first announcement on the double-helix structure for DNA. Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cell
All cells have several different abilities: (Mashburn et al, 1996) • Reproduction by cell division: (binary fission/mitosis or meiosis). • Use of enzymes and other proteins coded for by DNA genes and made via messenger RNA intermediates and ribosomes. • Metabolism, including taking in raw materials, building cell components, converting energy, molecules and releasing by-products. • Response to external and internal stimuli such as changes in temperature, pH or levels of nutrients. • Cell contents are contained within a cell surface membrane that is made from a lipid bilayer with proteins embedded in it.
Cell Types Eukaryote:
Prokaryotes:
Cell Types A.Prokaryotes: • • • • •
•
Bacteria & Archae Have no nucleus or membrane-bound organelles. Outside: flagella or pilli Enclosing: envelope cell wall Inside: - Cell genome (circular molecule) - Extrachromosomal DNA (plasmid) - 50S+30S ribosome RNA/protein synthesis coupled in cytoplasm
Structure External to the Cell Wall FLAGELLA Flagella are relatively long filamentous appendages consisting of a filament, hook and basal body Prokaryotic flagella rotate to push the cell, facilitate movement and communication between cells. Flagellar (H) protein functions as an antigen flagellin
Structure External to the Cell Wall FIMBRIAE (PILI) Many Gram negative bacteria possess rigid surface appendages,shorter and thinner than flagella called pili or fimbriae They are composed of structural protein subunits termed pilins Minor protein located at the tips of pili, are responsible for the attachment properties Two classes can be distinguished : ordinary pili, which play a role in the adherence of symbiotic and pathogenic bacteria to host cells, and sex pili, which are responsible for the attachment of donor and recipient cells in bacterial conjugation
The Cell Wall
Gram-positive cell walls consist of many layers of peptidoglycan and also contain teichoic acids Gram-negative bacteria have a lipopolysaccharide-lipoproteinphospholipid outer membrane surounding a thin peptidoglycan layer The outer membrane protects the cell from phagocytosis and from penicillin, lysozyme and other chemicals Porins are proteins that permit small molecules to pass through the outer membrane. The lipopolysaccharide consists of sugar (O polysaccharides) that function as antigens and lipid A, which is an endotoxin
Cell Types . Eukaryotes: contains membrane bound nucleus and organelles. Nucleus contain DNA (linear molecule with histone protein) Some eukaryotic organelles such as mitochondria contain some DNA RNA synthesis inside the nucleus Protein synthesis in cytoplasm Protist, fungi, plant, animal
Eukaryotic vs prokaryotic cells
Prokaryotes:
Eukaryotes:
• no membrane-bound nucleus
• DNA is located in membranebound nucleus
• transcription and translation are coupled
• Transcription and translation are separated in space and time
THE SIMILARITY BETWEEN PROKARYOTES AND EUKARYOTES
THE DIFFERENCES BETWEEN PROKARYOTES AND EUKARYOTES
Organelle
PROKARYOTES
EUKARYOTES
-
+
-
+
-
+
Golgi Apparatus
-
+
Endoplasmic Reticulum
-
+
Endomembrane Nuclear membrane Mitochondria/Chloroplas t
Cell division
Binary fission (simple division)
Mitosis (fission or budding) Meiosis
Prokaryotes
Eukaryotes
Typical organism
bacteria
Protist, fungi, plants, animals
Typical size
~1-10 μm
~10-100 μm
Type of nucleus
Nucleoid region; no real nucleus
Real nucleus with double membrane
DNA
Circular (usually)
Linear molecules
RNA-/protein synthesis
Coupled in cytoplasm
RNA_synth inside the nucleus; protein synth. In cytoplasm
ribosomes
50S + 30 S (70S)
60S + 40S (80S)
Eukaryotic Cell Types : Animal vs. Plant
Cell Types : Animal vs. Plant 1. Plant cells have chloroplasts 2. Plant cells have a cell wall 3. Plant cells have a large central vacuole 4. Animal cells have more lysosomes and vesicles
Cell Organelles
Cell Organelles • Organelle= “little organ” • Found only inside eukaryotic cells • All the stuff in between the organelles is cytosol that contain thousands of enzymes . • Everything in a cell except the nucleus is cytoplasm
Cell Anatomy •
Cell membrane – The outer layer of animal cells, found inside cell walls (if wall is present) – Controls what enters and leaves the cell – outside boundary – gives shape and flexibility – semi-permeable – made of lipids in 2 layers/ Phosoplipid bilayer – Protect cytoplasm & nucleus
A membrane around the cell is necessary for many reasons • Cell recognition and attachment involves membranes • Many metabolic functions, such as oxidative phosphorylation, are organized around membranes • Signal systems for cell regulation are based upon membranes
Cell Membrane 1. Integral membrane protein to active transport. 2. Trans-membrane protein/ peripheral protein
Phospolipid
Protein Transmembran Transport zat
•Protein tertanam pd lap lipid protein transmembrane •Protein yg mengapung diantara lipid protein integral •Proteins yg tdpt pd bag luar lipid bilayer peripheral
Nucleus • Control center of the cell • Contains DNA • Surrounded by a double membrane • Usually the easiest organelle to see under a microscope – Contains DNA found on chromatin strands – Materials pass in and out through the nuclear membrane
Fungsi nukleus • Menyimpan gen pada kromosom • Mengatur gen dlm kromosom dlm proses pembelahan sel • Mentransport faktor regulasi & produk gen melewati pori inti • Menghasilkan pesan (mRNA) yang mengkode protein • Menghasilkan ribosom dalam nukleus • Mengatur DNA uncoiling dlm replikasi gen
Nukleolus (anak inti) • Tdpt 1 / lebih, tdpt di dlm nukleus • Bbtk sferik sbg massa granul & fiber yg pekat • Merupakan tempat kromosom dg banyak kopi gen yg diperlukan utk sintesis ribosom, RNA & protein ribosom. Pd sel sehat dihasilkan 10.000 ribosom per menit.
Mitochondria
– Rod-shaped – Create energy for the cell from food – Converts the chemical energy stored in food into compounds more convenient for the cell to use. – Tempat respirasi seluler proses katabolik yg menghasilkan ATP dg mengekstraksi energi dari gula, lemak dan bahan bakar lain dgn bantuan oksigen. – Bukan bagian dari sistem endomembran – Memiliki ribosom dan DNA dlm jumlah sedikit. DNA inilah yg memprogram sintesis protein yg dibuat dlm ribosomnya sendiri
The Mitochondrial • Most of our body ’s nucleated cells contain 500 to 2000 mitochondria • In the cone cell photoreceptors of the eye, mitochondria make up 80% of the intracellular volume. • In extra-ocular muscles, they account for 60%, and in heart muscle they comprise 40% of the volume of the cell. • Nerve cells in the brain and muscles require a great deal of energy, and thus appear to be particularly damaged when mitochondrial dysfunction occurs.
The Mitochondrial • • •
In matrix the oxidation phosphorylation takes place. The Kreb Cycle takes place in the matrix . It contains three major proteins : 1) The electrone transport chain protein complex (I-IV). 2) an enzyme complex called ATP synthetase which makes ATP (V) and 3). transport proteins which regulate the transfer of molecules into and out of the matrix.
The Mitochondrial Chromosome • Mitochondria consist of 2 – 10 mtDNA Egg cytoplasma 200.000 – 300.000 mtDNA increase during oogenesis • mtDNA was found to vary according to cell type – Low in platelets (Platelets have only two to six mitochondria). – Red blood cells do not contain mitochondria • Highest in brain, liver, kidney
Endoplasmic Reticulum • Carry proteins and other materials through the cell • Connected to nuclear membrane • Highway of the cell • Rough ER: studded with ribosomes; it makes proteins
REK menghasilkan protein & menyusun membran • The rough ER manufactures membranes • Ribosomes on its surface produce proteins Transport vesicle buds off
4
Ribosome
Sugar chain
1 Polypeptide
3
Secretory (glyco-) protein inside transport vesicle
Glycoprotein 2
ROUGH ER
REH memiliki fungsi bervariasi • Smooth ER synthesizes lipids • In some cells, it regulates carbohydrate metabolism and breaks down toxins and drugs
Ribosome
Site of protein synthesis Produced in a part of the nucleus called
• Ribosome60S+40S • Found attached to rough ER or floating free in cytosol
Ribosom & Sintesis Protein
Ribosom • Pabrik utk sintesis protein • Dibangun dr molekul2 protein & rRNA • Pd sel prokariot, ribosom tdpt bebas dlm sitosol. Dlm sel eukariot ribosom tdpt bebas di sitosol, matriks mitokondria, stroma kloroplas, atau menempel pd permukaan selaput RE • RE kasar adl RE yg dilekati bnyk ribosom, RE halus tidak mengandung ribosom
Ribosom •
Ribosom tdr atas 2 bag tdk sama besar
•
Ukuran ribosom ditentukan dg analisis sedimentasi dg mengukur laju pengendapan dlm larutan kental (mis sukrosa) dg pemusingan kecepatan tinggi.
•
Koefisien sedimentasi ditentukan dg S (Svedberg) nama penemu ultracentrifuge
•
Ribosom prokariot memiliki koefisien sedimentasi 70S, ribosom eukariot
memiliki koefisien sedimentasi 80S
Ribosom • Ribosom prokariot tdr atas sub unit besar 50S & sub unit kecil 30S • Ribosom eukariot tdr atas sub unit besar 60S & sub unit kecil 40S • Ribosom mitokondria & kloroplas juga tdr atas 2 sub unit. Ribosom mitokondria bervariasi dr ukuran 55S pd hewan sampai 80S pd bbrp protozoa & jamur. Ribosom kloroplas adalah 70S pd semua sel hijau
Golgi Apparatus • Finish, sort, and “ship” many products of the cell • Synthesize macromolecules • Store and export products of E.R. • Deskripsi : Klp 5-8 kantung membran bbtk mangkuk ( cisternae ) dg ujung menggelembung & menempel satu sama lain.
Golgi Apparatus
Golgi aparatus • Bdn golgi bbtk polar, tdr atas bagian cis dmn protein masuk, & bagian trans dmn protein keluar. • Dibagi2 dlm kompartemen/ruang2 yg berbeda dg processing enzymes yg spesifik. • ± tdpt 20 bdn golgi pd tiap sel, vary depending on the function of the cell
What does it do? • Utk distribusi & pusat lalulintas produk kimia sel. • Memodifikasi protein & lipid & prepares them for exportation. • Uses sugar nucleotides to transport the proteins.
What else does it do? • It works with the endoplasmic reticulum. • It uses a Trans Golgi Network (TGN) to attach chemical “flags” on the exported proteins as sort of an address code so that they get to the right place in the cell.
What’s so Great about it? • Without the Golgi Apparatus, cells could not secrete important chemicals into our bodies such as: Hormones Enzymes (create chemical reactions) Antibodies ( keep us from getting ill and possibly dying)
Golgi Apparatus Golgi Body
Flattened sacs Receive proteins and other material, package them and ship them out
Golgi Apparatus
Lysosomes • Lysosome – Contain enzymes that function in digestion of food and dead cell parts (break down & worn out organelles) – Surrounded by a membrane – Small organelles filled with enzymes,
Lysosomes • Large vesicles formed by the Golgi • Garbage disposal of the cell • Contain digestive enzymes that break down wastes Which organelles do lysosomes work with?
Peroxisomes • They are similar to lysosome but smaller. • Mengandung enzim yg mentransfer hidrogen dari berbagai substrat ke oksigen, yg menghasilkan H2O2 sbg produk samping. • Bbrp peroksisom menggunakan O2 utk memecah as.lemak mjd molekul yg lbh kecil utk diangkut ke mitokondria sbg bahan bakar utk respirasi seluler. • Found mainly in liver and kidney cells • Main function is detoxification of toxic materials. • Dlm hati menawarkan racun alkohol & senyawa berbahaya lainnya dgn mentransfer hidrogen dari racun ke oksigen. H2O2 yg terbentuk tsb sebenarnya beracun, namun organel ini mengandung suatu enzim yg mengubah H2O2 menjadi air. • Pada tumbuhan glioksisom ditemukan dlm jaringan penyimpan lemak dari biji tumbuhan mengandung enzim yg menginisiasi pengubahan as.lemak mjd gula, yg dpt digunakan oleh biji yg sedang tumbuh sbg sumber energi & sumber karbon sampai biji tsb dpt menghasilkan gula sendiri melalui fotosintesis
Cytoskeleton
Roles of the Cytoskeleton: Support, Motility, and Regulation • •
• •
•
Acts as skeleton and muscle Provides shape and structure penting utk sel hewan yg tdk memiliki dinding sel Utk pergerakan organel2 didalam sel Motilitas sel interaksi antara sitoskeleton dg protein (molekul motor) mikrotubul & mikrofilamen Made of three types of filaments
Components of cytoskeleton: 1) Microfilaments (Filamen aktin) • Batang padat, berdiameter 7 nm. Filamen ini tdd molekul aktin (suatu protein globular) • Merupakan rantai ganda subunit aktin yg terlilit. • Peran: menahan tegangan (gaya tarik) mendukung bentuk sel • Sebagai bagian alat kontraksi sel otot bersamaan dg miosin
Components of cytoskeleton: 2) Intermediate filaments Intermediate filaments - Dinamai berdasarkan diameternya, lbh kecil drpd mikrotubula, lbh besar drpd mikrofilamen. - Spesialisasi utk menahan tarikan. Sangat penting utk dlm memperkuat bentuk sel dan menetapkan posisi organel tertentu
Components of cytoskeleton: 3) Mikrotubula • Memberi bentuk & mendukung sel, juga sbg jalur yg digunakan organel (yg dilengkapi dg molekul motor) utk dpt bergerak • Misal: menuntun vesikula sekretori dari AG ke membran plasma • Terlibat dlm pemisahan kromosom selama pembelahan sel
Cell Wall • Cell Wall – rigid layer of nonliving material – Provide protection & support – Found in plant, some bacteria, some protists and some fungi
Chloroplast • ChloroplastContains the green pigment chlorophyll • Site of food (glucose) production • Turn the Sun’s energy into food through photosynthesis • They do not make energy, they convert it
Vacuoles • Vacuole – Store food water and other materials – Small in animal cell – Large in plants • Store H2O • Help keep the plant upright
Vacuoles • Large central vacuole usually in plant cells • Many smaller vacuoles in animal cells • Storage container for water, food, enzymes, wastes, pigments, etc.
PLANT CELL Cell wall Membrane Cell Plastida Endoplasmic R Golgi Apparatus Vakuola
Sel tumbuhan berbeda dr sel hewan, krn tdk memp.: sentriol & filamen intermediat, namun memp. Plastida, ddg sel & vakuola berukuran besar.
