Top Banner
SUPARMI, S.Si, M.Si BAGIAN BIOLOGI FAKULTAS KEDOKTERAN UNISSULA Kuliah Transport melalui membran
53

transport membrane (lengkap)

Oct 20, 2015

Download

Documents

transport membrane (lengkap)
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: transport membrane (lengkap)

SUPARMI, S.Si, M.Si

BAGIAN BIOLOGI FAKULTAS KEDOKTERAN

UNISSULA

Kuliah

Transport melalui membran

Page 2: transport membrane (lengkap)

Pendahuluan

Transport Aktifb

Struktur dan Fungsi Membran Sel1

Transport Melalui Membran2

Transport Pasifa

Cotransportc

Exocytosis, Endocytosis & Transcytosisd

Page 3: transport membrane (lengkap)

F5-1

Membran Sel

Page 4: transport membrane (lengkap)

• Bagian terluar sel

• Membatasi bagian dalam dan lingk luar

• Sebagai reseptor (penerima) rangsang dari luar seperti hormon dan bahan kimia lain, baik dari lingk luar maupun dari dalam

• Melindungi isi sel agar tidak keluar

• Mengontrol zat yang keluar dan masuk

• Sebagai tempat terjadinya kegiatan biokimia (seperti reaksi oksidasi dan respirasi)

Fungsi Membran Sel

Page 5: transport membrane (lengkap)

Struktur Membran Sel

Page 6: transport membrane (lengkap)

Struktur Membran Sel

Fosfolipid

• HYDROPHILIC heads (water liking)-Attracted to the water

• called POLAR

• HYDROPHOBIC tails (water fearing)-Not attracted to the water

• called NON-POLAR

Page 7: transport membrane (lengkap)

Struktur Membran SelEffect of temperature on the packing of the

hydrocarbons

• Low temperatures the bilayer is in a gel state and tightly packed.

• At higher (body) temperatures the bilayer actually "melts' and the interior is fluid allowing the lipid molecules to move around, rotate, exchange places. This also allows movement of other components of the membrane.

Page 8: transport membrane (lengkap)

Struktur Membran SelStruktur Membran Sel

Cholesterol • Another type of lipid in the membrane

is cholesterol. The amount of cholesterol may vary with the type of membrane. Plasma membranes have nearly one cholesterol per phospholipid molecule. Other membranes (like those around bacteria) have no cholesterol.

Page 9: transport membrane (lengkap)

Struktur Membran Sel

Fungsi Cholesterol

1. They immobilize the first few hydrocarbon groups of the phospholipid molecules.

2. This makes the lipid bilayer less deformable and decreases its permeability to small water-soluble molecules. Without cholesterol (such as in a bacterium) a cell would need a cell wall.

3. Cholesterol prevents crystallization of hydrocarbons and phase shifts in the membrane.

Page 10: transport membrane (lengkap)

Struktur Membran Sel

Glikolipid 1.protective 2.insulators3.sites of receptor binding.

Page 11: transport membrane (lengkap)

Two major types of membrane proteins

• Look at the picture and notice the integral proteins and the peripheral proteins.

Struktur Membran Sel

PROTEIN

Page 12: transport membrane (lengkap)

Transmembrane or embedded proteins allowing for passage through the membranes hydrophobic region

Struktur Membran Sel

INTEGRAL PROTEIN

PERIFERAL PROTEIN

• Appendages to the membrane or may be found attached to integral proteins

Page 13: transport membrane (lengkap)
Page 14: transport membrane (lengkap)

Transport proteins

• Usually integral

• Specific for solute

• Some hydrolyze ATP

Struktur Membran Sel

Page 15: transport membrane (lengkap)

Sifat Membran Sel

+ dapat dilewati

- Tidak dapat dilewati

Page 16: transport membrane (lengkap)
Page 17: transport membrane (lengkap)

LALU LINTAS MATERIKELUAR MASUK SEL

1. Prinsip

a. Ada pergerakan materi keluar masuk

sel.

b. Nutrisi harus masuk.

c. Sampah harus keluar.

d. Ion bergerak keluar masuk.

Page 18: transport membrane (lengkap)

2. Mekanisme

a. Transpor pasif

- Difusi

Pergerakan partikel/molekul/ion terlarut dari tempat yang konsentrasinya tinggi ke tempat yang konsentrasinya lebih rendah.

- Osmosis

Pergerakan cairan pelarut melalui membran semipermeabel dari tempat yang konsentrasinya lebih rendah, ke tempat yang konsentrasinya lebih tinggi.

b. Transpor aktifPergerakan molekul/ion melawan gradien konsentrasinya dengan menggunakan energi yang dihasilkan sel itu sendiri.Mis : Pompa Natrium

Pompa CalsiumEndo/Eksositosis

LALU LINTAS MATERI KELUAR MASUK SEL

Page 19: transport membrane (lengkap)

Cell membrane

Inside cell Outside cell

TRANSPORT PASIF

DIFUSI

Page 20: transport membrane (lengkap)

Cell membrane

Inside cell Outside cell

diffusion

TRANSPORT PASIF

DIFUSI

Page 21: transport membrane (lengkap)

Cell membrane

Inside cell Outside cell

EQUILIBRIUM

TRANSPORT PASIF

DIFUSI

Page 22: transport membrane (lengkap)

1. Oxygen – Non-polar so diffuses very quickly.

1. Carbon dioxide – Polar but very small so diffuses quickly.

2. Water – Polar but also very small so diffuses quickly.

TRANSPORT PASIF

Zat-zat yang berdifusi

Page 23: transport membrane (lengkap)

1. Gradien konsentrasi zat

2.Temperature.

3.Luas area permukaan/ ukuran molekul

4.Tipe molekul atau ion yang berdifusi

TRANSPORT PASIF

Faktor-faktor yang mempengaruhi

kecepatan difusi

Page 24: transport membrane (lengkap)

• Large polar molecules such as glucose and amino acids, cannot diffuse across the phospholipid bilayer. Also ions such as Na+ or Cl- cannot pass.

• These molecules pass through protein channels instead. Diffusion through these channels is called FACILITATED DIFFUSION.

• Movement of molecules is still PASSIVE just like ordinary diffusion, the only difference is, the molecules go through a protein channel instead of passing between the phospholipids.

TRANSPORT PASIF

Difusi terfasilitasi

Page 25: transport membrane (lengkap)

TRANSPORT PASIF

Difusi Terfasilitasi

Page 26: transport membrane (lengkap)

Cell membrane

Inside cell Outside cell

Protein channel

TRANSPORT PASIF

Difusi Terfasilitasi

Page 27: transport membrane (lengkap)

Cell membrane

Inside cell Outside cell

Protein channel

diffusion

TRANSPORT PASIF

Difusi Terfasilitasi

Page 28: transport membrane (lengkap)

Cell membrane

Inside cell Outside cell

Protein channel

diffusion

EQUILIBRIUM

TRANSPORT PASIF

Difusi Terfasilitasi

Page 29: transport membrane (lengkap)

• The cells of organisms

are surrounded by and

filled with fluids that are

made mostly of water.

• The movement of

(diffusion) of water

through cell membranes

is so important to life

processes that it has

been given a special

name- OSMOSIS

TRANSPORT PASIF

Osmosis

Page 30: transport membrane (lengkap)

• Osmosis : gerakan air dari potensial air lebih tinggi ke potensial air lebih rendah melewati membran selektif permeabel sampai dicapai keseimbangan dinamis

TRANSPORT PASIF

Osmosis

Page 31: transport membrane (lengkap)

Cell membrane

partially

permeable.

Inside cell Outside cellVERY High conc.

of water

molecules. High

water potential.

VERY Low conc.

of water

molecules. High

water potential.

Sugar molecule

DILUTE SOLUTIONCONCENTRATED SOLUTION

TRANSPORT PASIF

Osmosis

Page 32: transport membrane (lengkap)

Cell membrane

partially

permeable.

Inside cell Outside cellHigh conc. of

water molecules.

High water

potential.

Low conc. of

water molecules.

High water

potential.OSMOSIS

TRANSPORT PASIF

Osmosis

Page 33: transport membrane (lengkap)

Cell membrane

partially

permeable.

Inside cell Outside cell

OSMOSIS

EQUILIBRIUM. Equal water concentration on each side.

Equal water potential has been reached. There is no net

movement of water

TRANSPORT PASIF

Osmosis

Page 34: transport membrane (lengkap)
Page 35: transport membrane (lengkap)

• Osmosis important to cellular functions.

• RBC (red blood cells) are swimming in plasma which is mostly water with salts, sugars, and other nutrients.

TRANSPORT PASIF

The cell & Osmosis

Page 36: transport membrane (lengkap)

What is effect of immersing an animal cell in a

hypertonic or hypotonic solution?

Page 37: transport membrane (lengkap)

TRANSPORT PASIF

Effect of Water on RBC

Page 38: transport membrane (lengkap)

• Isotonic – solutions with the same solute concentration as that of the cytosol

• Hypertonic – solutions having greater solute concentration than that of the cytosol; water leaves the cell causing crenation(shrinkage)

• Hypotonic – solutions having lesser solute concentration than that of the cytosol; water enters the cell causing swelling and potential lysis

TRANSPORT PASIF

Effect of Water on RBC

Tonicity – how a solution’s osmolarity affects cell volume

Page 39: transport membrane (lengkap)

Types of Active Transport

Primary active transport:

hydrolysis of ATP

phosphorylates the transport

protein causing conformational

change

Secondary active transport:

use of an exchange pump

(such as the Na+-K+ pump)

indirectly to drive the transport

of other solutes

Symport system – two

substances move across a

membrane in the same

direction (also called

cotransport)

Antiport system – two

substances move across a

membrane in opposite

directions (also called

countertransport)

TRANSPORT AKTIFTIPE

Page 40: transport membrane (lengkap)

Active Transport – requires a cell uses energy to move molecules across the membrane.

Page 41: transport membrane (lengkap)
Page 42: transport membrane (lengkap)

Active Transport Active transport - movement of materials

AGAINST the concentration gradient from low concentration to high concentration

Requires the cell to use energy (ATP)‏

2 kinds:

1. membrane pumps

2. vesicle transports

Page 43: transport membrane (lengkap)

Active Transport

• Active transport proteins:

– Move substrates against concentration gradient

– Require energy, such as ATP

– Ion pumps move ions (Na+, K+, Ca+, Mg2+)

– Na+-K+ Exchange Pump moves both of these ions at the

same time, each in the opposite direction (called antiport or

countertransport)

– Proton Pump uses photosynthesis or food energy to create

a proton concentration gradient that then is used to

manufacture ATP

Page 44: transport membrane (lengkap)

Sodium-Potassium Exchange Pump

Active transport, carrier mediated:

1 ATP moves 3 Na+ out 2 K+ in

This creates an electrical potential across the membrane

Called the Transmembrane Potential

Page 45: transport membrane (lengkap)

Transmembrane Potential• Voltage across a membrane

• Resting membrane potential –the point where K+ potential is balanced by the membrane potential

– Ranges from –20 to –200 mV

– Results from Na+ and K+

concentration gradients across the membrane

– Differential permeability of the plasma membrane to Na+

and K+

• Steady state potential is maintained by active transport of ions

Page 46: transport membrane (lengkap)

– Expends metabolic energy to

pump protons across membranes

Proton Pump (in Mitochondrial Membranes)

Proton PumpPLAY

Page 47: transport membrane (lengkap)

Vesicular Transport

• Also called bulk transport

• Transport of large particles and macromolecules across plasma

membranes

Directional Descriptive Terms

– Exocytosis – moves substance from the cell interior to the extracellular

space

– Endocytosis – enables large particles and macromolecules to enter the

cell

• Receptor-mediated

• Pinocytosis

• Phagocytosis

Functional Descriptive Terms

– Transcytosis – moving substances into, across, and then out of a cell

– Vesicular trafficking – moving substances from one area in the cell to

another

– Phagocytosis – pseudopods‏engulf‏solids‏and‏bring‏them‏into‏the‏cell’s‏

interior

Page 48: transport membrane (lengkap)

Receptor-Mediated Endocytosis

• Receptors (glycoproteins called clathrin) bind target

molecules (ligands)

• Coated vesicle (endosome) carries ligands and

receptors into the cell

Page 49: transport membrane (lengkap)

• Pinocytosis (cell drinking)

• Endosomes‏“drink”‏extracellular‏fluid

Page 50: transport membrane (lengkap)

• Phagocytosis (cell eating)

– pseudopodia (psuedo = false,

podia = feet)

– engulf large objects in

phagosomes

Page 51: transport membrane (lengkap)

Getting the Big Stuff In and OutExocytosis

• Is the reverse of endocytosis

Page 52: transport membrane (lengkap)

Summary

Page 53: transport membrane (lengkap)