membran dan transport zat2011
TRANSCRIPT
Evi Umayah Ulfa, M.Si., Apt
KULIAH BIOLOGI DASAR
Komponen Penyusun Kimia Sel,
Membran dan Transport Zat
Komponen Kimia Sel
Organik
• Gula (HA)
• Lemak
• Protein
• Nukleotida
Anorganik
• Air
• Gas : O2,N2
• Mineral : P, O, K, S, Ca, Fe, Mg, Na, Cl, Cu, Mn, Zn, dan Mo
ASAM LEMAK
Asam Amino
Protein
Evi Umayah Ulfa, M.Si., Apt
MEMBRAN SEL
Membrane Cell
Membran plasma
Membran dalam
(Internal Membrane)
Component of membrane
• Lipid
– Amfifatik
• Hidrofob : asam lemak
(jenuh, tidak jenuh)
• Hidrofil : fosfat
– Molekul penyusun lipid
membran:
• Fosfolipid
• Kolesterol
• Glikolipid
• Protein
Membrane Lipids
Characteristic of Membrane
• Membrane Lipids Are Amphipathic
Molecules
• The Lipid Bilayer Is a Two-dimensional
Fluid
The degree of bilayer fluidity depends on the
lipid composition, structure of the
phospholipid hydrophobic tails, and
temperature
• The Lipid Bilayer Is Asymmetrical
Fluiditas Membran Sel
Protein pada
Membran
• Sel yang berbeda memiliki
membran protein yang berbeda
pula
• Berbagai membran di dalam sel
memiliki kumpulan protein yang
unik
• Proteins : fusngsi spesifik pada
membran
• Tipe protein pada membran :
• Integral MP/Transmembrane
• Lipid anchored MP
• Peripheral MP
Fungsi protein pada membran
Membran fosfolipid
IMPERMEABEL ( ion,
molekul besar tidak
bermuatan, molekul
yang bermuatan)
TRANSPOR ZAT
Transpor Pasif dan Aktif
Transpor Pasif
• Difusi
– Lemak, gas permiabel
• Difusi terfasilitasi
– Dibantu oleh transporter, Channel
• Osmosis
– Difusi air
Difusi
• Perpindahan Solut Tinggi ke Rendah
• Tidak memerlukan energi
• Berhenti jika telah setimbang
Difusi Pasif
Difusi Terfasilitasi
• Two major classes of membrane transport
proteins:
– carrier proteins (carriers, permeases, or
transporters)
– channel proteins form hydrophilic pores that
extend across the lipid bilayer; when these
pores are open, they allow specific solutes
(usually inorganic ions of appropriate size and
charge) to pass through them and thereby cross
the membrane
Transporter and Channel
Transporter/Carier
Chanel Protein
Transporter
Osmosis
• Difusi air melalui
membran
semipermeabel
• Konsentrasi
Tinggi rendah
• Solut tidak
berpindah
(besar)
Transport Aktif
• Rendah Tinggi
• Butuh Energi
• Ada 3 tipe
– Pompa protein
– Endositosis
– Eksositosis
Pompa Protein
• Protein transpor
(transporter) yang
membutuhkan energi
supaya bisa bekerja
(berubah konformasi)
• Contoh :
– Pompa Na/ K
respon sistem syaraf
ATP
Simporter/Antiporter/Uniporter ????
Endositosis
• Masuknya molekul
ke dalam sel
melalui
vesikel/vakuola
• Perlu Energi
• Contoh :
fagositosis oleh sel
darah merah
phagocytosis
pinocytosis
receptor-mediated
endocytosis
fuse with
lysosome for
digestion
non-specific
process
triggered by
molecular
signal
Eksositosis
• Perpindahan keluar molekul besar dari sel
melalui vesikel/vakuola
• Perubahan sel butuh Energi
• Sekresi Hormon keluar sel
EFEK OSMOSIS BAGI
KEHIDUPAN SEL
Konsentrasi
• Hipertonis
– High solute; Low water
• Hipotonis
– Low solute; High water
• Isotonis
– Solut and Water equal
Hypotonic Solution
Result: Water moves from the solution to inside the
cell): Cell Swells and bursts open (cytolysis)!
Hypertonic Solution
Result: Water moves from inside the cell into the
solution: Cell shrinks (Plasmolysis)!
• OsmosisAnimations for
isotonic, hypertonic, and hypotonic
solutions
shrinks
Isotonic Solution
Result: Water moves equally in both directions and
the cell remains same size! (Dynamic Equilibrium)
What type of solution are these cells in?
A CB
Hypertonic Isotonic Hypotonic
How Organisms Deal with
Osmotic Pressure
•Bacteria and plants have cell walls that prevent them from
over-expanding. In plants the pressure exerted on the cell
wall is called tugor pressure.
•A protist like paramecium has contractile vacuoles that
collect water flowing in and pump it out to prevent them
from over-expanding.
•Salt water fish pump salt out of their specialized gills so
they do not dehydrate.
•Animal cells are bathed in blood. Kidneys keep the blood
isotonic by remove excess salt and water.