Science 7 - LAND and SEA BREEZE and its Characteristics
Movement of substances
1.
2.
3. Substances needed by the cellsSubstances needed by the cells
WaterWater
OxygenOxygen
NutrientNutrient
– GlucoseGlucose
– Amino acidAmino acid
– MineralMineral
– Fatty acidFatty acid
– VitaminVitamin
The substances have to move across theThe substances have to move across the
membranemembrane
4. Substances to be eliminate fromSubstances to be eliminate from
the cellsthe cells
Carbon dioxideCarbon dioxide
UreaUrea
ToxinToxin
5.
6. Fluid Mosaic ModelFluid Mosaic Model
1972 - Singer and Nicolson called the1972 - Singer and Nicolson called the
membrane amembrane a “Fluid Mosaic Model”.“Fluid Mosaic Model”.
Mosaic:Mosaic: different proteinsdifferent proteins
embedded inembedded in thethe
phospholipids.phospholipids.
Fluid:Fluid: proteins and phospholipids canproteins and phospholipids can
move freely in themove freely in the
membrane.membrane.
7.
8.
9.
10. Components of a phospholipidComponents of a phospholipid
bilayer.bilayer.
1.1. phospholipidsphospholipids
2.2. proteins -proteins - enzymes, receptors,enzymes, receptors,
transport.transport.
3.3. glycolipidsglycolipids
4.4. glycoproteinsglycoproteins
5.5. carbohydratescarbohydrates
6.6. cholesterolcholesterol
11. Plasma MembranePlasma Membrane
Boundary that separates theBoundary that separates the living cellliving cell
from it’sfrom it’s non-livingnon-living surroundings.surroundings.
Phospholipid bilayerPhospholipid bilayer
AmphipathicAmphipathic - having both:- having both:
hydrophilic headshydrophilic heads
hydrophobic tailshydrophobic tails
~8 nm thick~8 nm thick PhospholipidPhospholipid
12.
13.
14.
15. Controls trafficControls traffic into and out of the cellinto and out of the cell
withwith phospholipidsphospholipids andand transporttransport
proteinsproteins..
Selectively permeableSelectively permeable
>>> semi-permeable>>> semi-permeable
Transport proteinTransport protein
16. What is Selective Permeability?What is Selective Permeability?
TheThe propertyproperty ofof biological membranesbiological membranes
which allows some substances to crosswhich allows some substances to cross
more easily than others.more easily than others.
18. Through phospholipids layer:
Non polar molecules = Oxygen. Carbon
dioxide, water , lipid soluble molecules
By pore – proteins : water
soluble molecules and ions
By carrier- proteins and energy : ions.
By carrier- proteins : glucose, amino acids.
19. Passive transport:Passive transport: NONO energyenergy is expended.is expended.
– Simple diffusion – gases,Simple diffusion – gases,
– Osmosis – waterOsmosis – water
facilitated diffusion:facilitated diffusion:
type oftype of passive transportpassive transport which useswhich uses transporttransport
proteins.proteins.
–– glucose and amino acidglucose and amino acid
Active transport :Active transport :
– Using carrier protein and energy – ionsUsing carrier protein and energy – ions
20. DiffusionDiffusion
The net movement of a substance
(molecules) down a concentrationconcentration
gradientgradient from an area of highhigh
conconcentrationcentration to an area of lowlow
concentrationconcentration.
21.
22.
23.
24.
25.
26. Facilitated diffusionFacilitated diffusion
Allows diffusion of large, membrane insoluble compoundsAllows diffusion of large, membrane insoluble compounds
such as sugars and amino acidssuch as sugars and amino acids
Does not require energy (passive)Does not require energy (passive)
Highly SelectiveHighly Selective
Substance binds to membrane- transport proteinSubstance binds to membrane- transport protein
Fully reversible - molecules may enter the cell and leaveFully reversible - molecules may enter the cell and leave
the cell through the transport protein.the cell through the transport protein.
Particles move from areas of high concentration to areas ofParticles move from areas of high concentration to areas of
low concentration.low concentration.
Movement rate of particles will saturateMovement rate of particles will saturate
– Maximum rate limited by number of transportersMaximum rate limited by number of transporters
– Once all transporters are operating at 100%, an increase inOnce all transporters are operating at 100%, an increase in
concentration will not increase rateconcentration will not increase rate
27.
28.
29. Active TransportActive Transport
Movement across membrane with anMovement across membrane with an
energy cost (usually against concentrationenergy cost (usually against concentration
Used to pump specific compounds in orUsed to pump specific compounds in or
out of the cellout of the cell
Requires energy to overcome theRequires energy to overcome the
concentration gradient or to allow a largeconcentration gradient or to allow a large
or charged particle to cross membraneor charged particle to cross membrane
Requires specific integral membraneRequires specific integral membrane
proteinsproteins
– Can be saturated like facilitated diffusionCan be saturated like facilitated diffusion
proteinsproteins
– The energy requirement distinguishes activeThe energy requirement distinguishes active
transport from facilitated diffusiontransport from facilitated diffusion
30.
31.
32. OsmosisOsmosis
The movement ofThe movement of waterwater acrossacross
selectively permeable membranesselectively permeable membranes..
TheThe waterwater moves from amoves from a lowlow
concentration areaconcentration area toto highhigh
concentration areaconcentration area
33.
34.
35.
36.
37. Cell membranes are
completely permeable to
water, therefore, the
environment the cell is
exposed to can have a
dramatic effect on the cell.
43. Hypertonic Solution:
• Solute concentration of solution higher than cell
• More dissolved particles outside of cell than
inside
of cell
• Hyper = more (think hyperactive); Tonic =
dissolved particles
• Water moves out of cell into solution
• Cell shrinks
44. Hypotonic Solution:
• Solute concentration of solution lower than cell
• Less dissolved particles outside of cell than
inside of cell
• Hypo = less, under (think hypodermic,
hypothermia);
Tonic = dissolved particles
• Water moves into cell from solution
• Cell expands (and may burst)
