movement in and out of a cell Flashcards
What causes simple diffusion
The colliding of particles result in a net movement of particles from high concentration to low concentration .
Diffusion exists where
A concentration gradient is present
What is a concentration gradient ?
The difference in concentration between two regions.
In a closed system after a while diffusion results in
Equilibrium
The rate of diffusion increases
High concentration gradient Heat Small molecules Surface area to volume ratio is high Gas
Homeostasis
Maintenance of internal environment although external and internal environments may change
Examples of internal environment
Tissue fluid
Plasma
Lymph
The features of a cell that enable it to pass through a membrane
Size
Electrical charge
Lipid solubility
Can ions go through membrane?
No
Lipid soluble molecules ( lipophilic)
Ester
Ether
Alcohol
Chloroform
How does water go through ?
Aquaporins
Small amounts of substances could go through by these types of diffusion
Simple (passive)
Active
Large molecules could be transported through types of diffusion
Endocytosis - phagocytosis , pinocytosis
Exocytosis
Special features of facilitated diffusion
More rapid than simple
Specific
Saturated as transport increases
Competition is created due to the fact that transport if one substance will inhibit the transport of another
Channel protein
Hydrophilic
Controlled by signal systems
Three types
Three types of channel proteins
Voltage gated channels
Ligand gated channels
Mechanical gated channels
Voltage gated channels
Open and close in response to changes in voltage
Ligand gated channels
Gates activated by special substances
Mechanical gated channels
Activated by physical substances
osmosis
the net passive movement of free water molecules from an area of high concentration to an area of low concentration
what does osmosis require for it to happen?
semi permeable membrane.
what form is solute usually in? solvent?
solid, liquid
osmotic pressure
is the force that is applied to prevent water from flowing into a semi permeable membrane
osmotic potential
the ability of water to move from a hypotonic to a hypertonic solution
when making a salad you shoudn’t add salt
as salt is hypertonic compared to the vegetables’ inner environment and therefore water will diffuse out of the vegies. this is will make the salad watery.
Why is there a crunchy sound when biting into a celery?
vacuole is being broken
isotonic
solute concentration is the same as the surrounding environment of the cell
turgor pressure
the pressure AGAINST the cell wall of plants, fungi, bacteria and some protists by the water flowing in
when an animals cell is placed into a hypertonic solution the result is called
laking or crenation
when the animal cell is placed into a hypotonic solution the cell may be called
undergoing haemolysis
what is the advantage of turgor pressure for plants?
allows plants to be strong and allows stomata to be open.
why does strawberry jam not be spoilt when it is left open for a long time whereas milk is?
Strawberry jam is saturated with sugar. therefore it is hypertonic and therefore do not allow bacteria to grow on it as the cells are dehydrated.
Milk on the other hand, is not hypertonic and therefore does have a suitable environment to for bacteria to grow
what is the difference between incipient and full plasmolysis ?
incipient plasmolysis is when plant cell is able to recover from its state. only the vacuole shrink.
when is a cell flaccid?
cell shrinks when water leaves out of it.
active transport - some facts
1) carrier proteins can attach themselves to molecules and ions and convey them to the cytoplasm.
2) takes place in places where aerobic respiration happens
3) temperature, oxygen concentration may influence
What is active transport?
movement of substances across membranes that require an expenditure of energy.
molarity
concentration of a substance
the two main mechanisms that are used by active transport
1 - direct pumping coupled to ATP
2 - diffusion of one molecule down its electrogradient gradient is used to pump a second molecule against its electrochemical gradient.
bigger or smaller organisms have higher metabolic rates?
smaller
endotherms or ectotherms have higher metabolic rates?
endotherms
warm blooded
do endotherms or ectotherms have more permeable membranes?
endotherms
which fatty acids are essential to have a high metabolism?
omega 3, omega 6
reverse osmosis
pressure is applied to a highly concentrated solution to cause the solvent to diffuse to the lowly concentrated solution.
