Download Transport/Diffusion

Transport/Diffusion
Law of diffusion:
Kinetic energy:
(Thermal motion)
Equilibrium:
Passive Transport:
Osmosis: (dialysis)
Solution:
Solute: (
)
Solvent:
Universal Solvent:
Honors Biology
Trembly
Brownian Motion:
Cells must live in a proper water balance. Meaning, if they do not have enough water or
if they have too much water they will die. They must have the correct water concentration
to live. To study how cells live, we must consider the following 2 processes:
1) Solution concentration:
2) Membrane permeability:
The concentration of a solution involves the total concentration of all the dissolved
solutes within a solution: We do not consider the cell as part of the solution.
Ex:
Solution Concentration: If a cell lives in a beaker of water containing sodium 15%
and potassium 10% molecules, then the solution has 25% solute or salts and the rest of
the solution contains water (75% water).
Membrane permeability: This cell’s membrane has pores for sodium but not for
potassium. The cell allows sodium molecules to move in or out of the cell. However
potassium is only found outside the cell (a non-penetrating solute)
Influences on permeability:
Tonicity:
Tonic: In biology tonic means solutes in the solution. The tonic concentration is always
compared to the concentration inside the cell.
Hypotonic Solution:
Hypertonic Solution:
Isotonic Solution:
The cell itself has its own concentration of water and solutes, this is the cells cytoplasm.
Most cells cytoplasm has a concentration of about ______ solutes and ______ water.
The left side of the tube
is initially hypotonic
The right side of the tube
is initially hypertonic
Since this membrane is
impermeable to solutes, the
water will cross the membrane
to the hypertonic side.
Why does the water go to the hypertonic side?
All cells need to be in some degree of an aqueous (water) solution to maintain life.
Biology is concerned with living systems. Cells in the body are in a solution, the
extracellular solution (aka. Interstitial fluid) which is a watery fluid found just under
the skin and all the spaces outside of the body’s organs.
Below is a diagram of what happens to a blood cell in different types of solutions:
Known as cytolysis
Equilibrium
Known as plasmolysis
There are three tonic conditions
Outside-
Outside-
Outside-
Salts- high conc
Salts- low conc
Salts- equal conc
H2O- low conc
H2O- high conc
H2O- equal conc
Inside-
Inside-
Inside-
Salts- low
Salts- high
Salts- equal
H2O- high
H2O- low
H2O- equal
Hypertonic
Hypotonic
Isotonic
Environment high in salt
Environment low in salt
Cell loses water
Cell gains water
Leads to ___________
`
Plant cells in salt water
Leads to __________
Environment and cell of
equal salinity
No net gain or loss of water
No harm to cell
RBCs in freshwater
Saline solution
Osmoreguolation:
Dealing With Tonicity- Ecological Strategies
InSW-
InSW-
OutSW-
OutSW-
Saltwater Organisms
Freshwater Organisms
Problems1.
Problems1.
2.
2.
Solutions
Solutions
What about?
Anadromous fishes- ex:
Catadromous fishes- ex:
Cytolysis:
Plasmolysis:
Our blood cells need to be in an isotonic environment. Doctors often get a report on a
person’s electrolytes. Electrolytes are the solutes or salts in our blood. If the
electrolyte count is high (hypertonic condition) if the electrolyte count is low (hypotonic)
if the electrolytes are equal to the cell’s solute concentrations (isotonic).
*Plant cells have a cell wall which protects them from bursting
*Animal cell will burst when placed in a hypotonic solution.
When plant cells are placed in a hypertonic solution, water molecules will move out of
the cell. This dehydrates the cell and the cell becomes flaccid
Turgor pressure:
Protists deal with osmosis using this organelle ________________________
Water
movement
Cytoplasm
Outside
cell
Environmental Tonicity: Tonicity refers to the saltiness of the fluid environment a cell exists in. In nature a
similar measurement is salinity, such as in oceans (saltwater) and lakes (freshwater). Saltwater has more
salinity or a higher salt concentration.
Passive Transport
1. Simple Diffusion
2. Facilitated diffusion
Ex: insulin and glucose
3. Carrier Transport Across Membrane:
4. G-Protein Linked Receptors:
Name comes from ____________________________
Gated Ion Channels: Some pores open and close
1. Voltage Gated:
2. Chemical Gated:
Active Transport:
Sodium / Potassium Pump:
Diagram-
Integrated Transport SystemsHow do you get large polar molecules through the membrane when they are too
large to fit through the protein passages?
ENDOCYTOSIS: How large solutes or large amounts of solutes get into the cell.
STEPS
1.
2.
3.
4.
2 Types of Endocytosis
Phagocytosis:
Pinocytosis:
EXOCYTOSIS:
STEPS
1.
2.
3.
4.