Cell Membrane Transport
Cell membrane transport
There are 2 types of cell membrane transport:
Passive Transport Substance move fromHigh concentration to low concentration-no energy required
Active Transport Substance move fromlow concentration to high concentration-energy (ATP) required
Another perspective on passive and active transport
Passive Transport
DiffusionThe movement of particles from areas of high
concentration to low concentration
Diffusion
Factors that influence the rate of diffusionTemperaturePressure Electrical currentsMolecular size
Equilibrium
the concentrations of particles are the same on both sides of the membrane
Facilitated Diffusion
Particles flow from high concentration to low concentration but this time they need the help of proteins to get through the cell membrane.
Facilitated diffusion
Osmosis
The diffusion of water across a selectively permeable membrane
Important in maintaining cell homeostasis Water flows to side of membrane where the water
concentration is lower until equilibrium is reached
Osmosis
Osmosis is controlled by the amount of solutes on either side of a membrane
Osmosis – Types of Solutions
When dealing with osmosis, water can either move into the cell or out of it.
The solute cannot move to equal out the concentration of solutions, so the water has to.
We describe the solutions that cells are in as either hypotonic, isotonic, or hypertonic.
Isotonic Solution
Isotonic solution – Concentration of solute is the same in the cell and the area around the cell.
Water moves in and out at equal rates.
Isotonic solution
Hypotonic Solution
Hypotonic Solution – Concentration of solute is lower in the solution than in the cell.
Net movement of water INTO the cell.
Hypotonic solutions
Since water moves into the cell the cell, animal cells can explodeCytolysis
Plant and animal cells in a hypotonic solution
Turgor Pressure – central vacuole is full; pressure against the cell wall
Hypertonic Solution
Hypertonic solution – concentration of solute is higher in the solution than in the cell.
Net movement of water OUT of the cell.
Hypertonic solutions
Since water moves out of the cell the cell will shrink
Plant and animals cells in a Hypertonic Solution
Plasmolysis: shrinking of cytoplasm due to osmosis
Active Transport
Molecules move from low concentration to high concentrationRequires energy….why?
Active Transport
Molecular TransportProtein Pumps
Small molecules and ions carried across the cell membrane by proteins in the membrane that act like pumps (low high)
Bulk TransportEndocytosis – in!Exocytosis – out!
Sodium Potassium Pump
Other membrane transport activities that require energy
EndocytosisEngulfing of large particles or liquids from
outside the cell
2 types of Endocytosis
PhagocytosisEngulfing of large particles from outside the cell
PinocytosisEngulfing of liquids from outside the cell
Other membrane transport activities that require energy
ExocytosisRelease of large particles or liquids from
inside the cell
Inside the cell
Outside the cell
Which of the following allows cells to recognize each other as self or foreign?
Channel Pro
tei...
Cholestero
l
Phospholip
ids
glyco
prote
ins
0% 0%0%0%
1. Channel Proteins
2. Cholesterol
3. Phospholipids
4. Glycoproteins
10
The inside of the cell membrane consists of
Phosphate head
...
Fatty acid
tai...
Extra
cellu
lar ...
Carbohydrate
c...
0% 0%0%0%
1. Phosphate heads
2. Fatty acid tails
3. Extracellular Matrix
4. Carbohydrate chains
10
Which of the following components of the cell membrane affects the fluidity of the cell membrane?
Glyc
oproteins
Glyc
olipids
Cholestero
l
Extra
cellu
lar ...
0% 0%0%0%
1. Glycoproteins
2. Glycolipids
3. Cholesterol
4. Extracellular matrix
10
Which type of protein is responsible for receiving messages from hormones?
Channel pro
tei...
Carrier p
rotei...
Cell Reco
gniti...
Recepto
r Pro
te...
0% 0%0%0%
1. Channel protein
2. Carrier protein
3. Cell Recognition Protein
4. Receptor Protein
10
The movement of particles from high concentration to low concentration is called
Osm
osis
Diff
usion
Endocy
tosis
Exocy
tosis
0% 0%0%0%
1. Osmosis
2. Diffusion
3. Endocytosis
4. Exocytosis
10
The diffusion of water is called
Active
transp
ort
Endocy
tosis
Exocy
tosis
Osm
osis
0% 0%0%0%
1. Active transport
2. Endocytosis
3. Exocytosis
4. Osmosis
10
The movement of particles across a membrane that requires energy (ATP) is called
Passive
transp
...
Active
transp
o...
Aquaporins
Semi-p
ermeable...
0% 0%0%0%
1. Passive transport
2. Active transport
3. Aquaporins
4. Semi-permeable
10
This diagram is an example of what membrane transport?
Diff
usion
Fac
ilita
ted
diffus
ion
Endoc
ytosi
s
Exo
cyto
sis
0% 0%0%0%
1. Diffusion
2. Facilitated diffusion
3. Endocytosis
4. Exocytosis 10
This diagram is an example of what membrane transport?
Diff
usion
Fac
ilita
ted
diffus
ion
Endoc
ytosi
s
Exo
cyto
sis
0% 0%0%0%
1. Diffusion
2. Facilitated diffusion
3. Endocytosis
4. Exocytosis 10
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