SEL: Teori, Struktur, Organela. drg. Amandia Dewi Permana Shita, M.Biomed

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SEL:

Teori, Struktur, Organela

(2)

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”

(3)

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

Paramecium

(4)

Cell Theory

1838: German

botanist

Schleiden:

concluded that all

plants are made of

cells.

ONION CELLS

(5)

Cell Theory

1839. German

biologist

Theodor

Schwann

stated that

all animals are made

of cells.

A. Gut B. brain C. bone marrow d. cartilage e. muscle F. kidney

(6)

Cell Theory

Cell is the smallest

unit of life.

Every living thing

is made up of one

or more cells.

Human Liver Cells

Human skin cell

•Humans have an estimated

100 trillion cells.

•The largest known cell is an

unfertilized

egg cell

(7)

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

(8)

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

(9)

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.

(10)

Cell Types

Prokaryotes:

Eukaryote:

(11)

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

(12)

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}

(13)

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

(14)

The Cell Wall

 Gram-positive cell walls consist of

many layers of peptidoglycan and also contain teichoic acids

 Gram-negative bacteria have a lipopolysaccharide-lipoprotein-phospholipid 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

(15)

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

(16)

Eukaryotic vs prokaryotic cells

Prokaryotes:

• no membrane-bound nucleus • transcription and translation are coupled

Eukaryotes:

• DNA is located in membrane-bound nucleus

• Transcription and translation are separated in space and time

(17)

THE SIMILARITY BETWEEN PROKARYOTES

AND

(18)

Organelle

--

+

--

+

--

+

--

+

--

+

EUKARYOTES PROKARYOTES Endomembrane Nuclear membrane Mitochondria/Chloroplas t Golgi Apparatus Endoplasmic Reticulum

THE DIFFERENCES BETWEEN PROKARYOTES AND

EUKARYOTES

(19)

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

(20)

Eukaryotic Cell Types :

Animal vs.

Plant

(21)

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

(22)

Cell Organelles

(23)

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

(24)

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

(25)

• 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

A membrane around the cell is

necessary for many reasons

(26)

Cell Membrane

1. Integral membrane protein to active transport. 2. Trans-membrane protein/ peripheral protein Protein Transmembran Transport zat Phospolipid

(27)

•Protein tertanam pd lap lipid  protein

transmembrane

•Protein yg mengapung diantara lipid 

protein integral

•Proteins yg tdpt pd bag luar lipid bilayer 

(28)

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

(29)

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

(30)

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.

(31)

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

(32)

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.

(33)

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.

(34)

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

(35)

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

(36)

REK menghasilkan protein & menyusun

membran

• The rough ER manufactures membranes

• Ribosomes on its surface produce proteins

1 ₂ 3 4 Transport vesicle buds off Ribosome Sugar chain Glycoprotein ROUGH ER Polypeptide Secretory (glyco-) protein inside transport vesicle

(37)

REH memiliki fungsi bervariasi

• Smooth ER synthesizes lipids

• In some cells, it regulates carbohydrate

metabolism and breaks down toxins and

drugs

(38)

Ribosome

• Ribosome60S+40S

• Found attached to

rough ER or floating

free in cytosol



Site of protein

synthesis



Produced in a part of

the nucleus called

the

(39)

(40)

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

(41)

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

(42)

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

(43)

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 &

(44)

(45)

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

(46)

What does it do?

• Utk distribusi & pusat

lalulintas produk kimia

sel.

• Memodifikasi protein &

lipid & prepares them

for exportation.

• Uses sugar nucleotides

to transport the

(47)

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.

(48)

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

(49)

Golgi

Apparatus

Golgi Body



 Flattened sacs_{Flattened sacs}  Receive Receive proteins and proteins and other material, other material, package them package them

and ship them

out

(50)

(51)

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,

(52)

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?

(53)

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

(54)

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

(55)

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

(56)

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

(57)

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

(58)

Cell Wall

• Cell Wall

– rigid layer of nonliving

material

– Provide protection &

support

– Found in plant, some

bacteria, some protists

and some fungi

(59)

Chloroplast

• Chloroplast

Contains 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

(60)

Vacuoles

• Vacuole

– Store food water and

other materials

– Small in animal cell

– Large in plants

• Store H2O

• Help keep the plant upright

(61)

Vacuoles

• Large central

vacuole usually in

plant cells

• Many smaller

vacuoles in animal

cells

• Storage container

for water, food,

enzymes, wastes,

pigments, etc.

(62)

Membrane Cell Vakuola Plastida Endoplasmic R Golgi Apparatus Cell wall

PLANT CELL

Sel tumbuhan berbeda dr sel hewan, krn tdk memp.: sentriol & filamen intermediat, namun memp. Plastida, ddg sel & vakuola berukuran besar.

(63)