Cell Structure and Function - Universitas...

Cell Structure and

Function

UMUM

• Sel unit struktural dan fungsional dr

kehidupan

• cell theory: all living things are composed of

cells, and new cells arise only from preexisting

cells

• Jenis sel berdasar internal organization

– Eukaryotes : has compartmentalized cytoplasm with

membrane-bounded organelles including a nucleus

– Prokaryotes

Cell Types

Prokaryotes:

Single cell

Eukaryote:

Single cells, colonies, multi-cellular

Eukaryotic Cell Types : Animal vs.

Plant

http://micro.magnet.fsu.edu/cells/animals/animalmodel.html

http://micro.magnet.fsu.edu/cells/plants/plantmodel.html

The CELL

Membran sel

Membran system

Membranous organella

Nonmembranous

CYTOPLASMA VS

CYTOSOL

ORGANELLA

√

Terdiri Biomembran

Cytoplasm consists of all the cellular contents

between the plasma membrane and the nucleus,

and has two components:

(1) the cytosol = (intracellular fluid), water,

proteins, lipids, carbohydrates, & electrolytes.

It contains masses of insoluble materials

known as inclusions, or inclusion bodies

(ex:glikogen)

(2) Organelles = specialized structures within

thecell that have characteristic shapes; they

perform specific functions

Membran sel

Membran system


Nonmembranous

CYTOPLASMA VS

CYTOSOL

ORGANELLA

√ Terdiri Biomembran

• The total surface area of internal membranes far

exceeds that of the plasma membrane

• ! membran internal/organel : membungkus organel

maintain discrete biochemical environments

• Komposisi membran sel ~ membran internal :

consist of lipids, proteins, and carbohydrates.

• 3 major classes of lipid: phospholipids,

glycolipids, and cholesterol

• 4 major types of phospholipid : sphingomyelin,

phosphatidylcholine, phosphatidylserine, &

phosphatidylethanolamine

Membran Sel

• Komponen :

1. Phospholipid : one polar

(hydrophilic) head and two

nonpolar (hydrophobic) fatty acid

tails = lipid bilayer

membrane surface

Unidentical membrane surface

noncovalent bonds

Cholesterol (dlm plasmalemma)

can limit lateral fluid movement

contribute to the mechanical

stability of the plasmalemma.

E-face

P-face

Lipid rafts are microdomains containing

cholesterol, sphingolipids, and certain

membrane proteinsn sites for signaling

across the plasma membrane

2. Karbohidrat :

• p.u sbg oligosakarida dlm glikoprotrein atau

glikolipid

• Glycolipids : lipids with attached sugar

residue (Sugar residues usually extend from

the external surface)

• struktur permukaan bercabang (=glycocalyx),

utk adhesi, cell-to-cell and cell-to-interstitial

matrix interactions; termasuk reaksi imun..

Membran Sel

Membran Sel 3. Protein p.u bentuk globular

Macam : * Protein membran integral

terikat erat dalam lapisan fosfolipid

* Protein membran perifer

berikatan scr longgar pada

permukaan, dg ikatan ionik

function : transport, receptors signals, attach

elements of the cytoskeleton, attach cells to the

extracellular matrix (cell adhesion molecules),

enzymatic activity when stimulated

Membran Sel

membran plasma: membungkus sel

integritas struktur dan fungsi

Memisahkan dengan lingkungan sekitar

mengatur lalu-lintas molekul keluar/masuk sel

selectively (semi) permeable

Komunikasi & interaksi antar sel

Signaling (transduksi signal ekstrasel intra)

Mempertahankan perbedaan potensial

Membrane transport

Passive transport

• difusi & osmosis

? ?

pasive

Passive

Processes of

Membrane

Transport

Active transport

• = energy-requiring process

1. Na+–K+ pump : antiport transport

2. Glucose transport : involves the symport

3. ATP-binding cassette transporters (ABC-

transporters) : transmembrane proteins that

have two domains

other

• Endocytosis membran menyelubungi

substansi extrasel sitoplasma (dalam vesikel

membran).

Cara : - fagositosis

- Pinocytosis

- Endocytosis dimediasi reseptor

specific reactions as trigger

• Exocytosis mngeluarkan substansi dr sel.

Dg vesikel fusi dg membran keluar

Microvilli

• Extensions of the

Plasmalemma

diperkuat mikrofilamen

• Terpancang pada

terminal web

Membran sel

Membran system


Nonmembranous

CYTOPLASMA VS

CYTOSOL

ORGANELLA √

Terdiri Biomembran

√

MEMBRANOUS

ORGANELLA

Mitochondria

Endoplasmic reticulum

Golgi

apparatus

lysosomes