Movement Of Substances Flashcards
what is Simple diffusion
The net random movement of particles down a concentration. It is a passive process. The steeper the gradient and the higher the temperature the greater the rate of diffusion.
Example would be oxygen
What is meant by passive transport
That no external energy is needed
what is Facilitated diffusion
The passive movement of molecules down a concentration gradient across a membrane and involves special carrier and channel proteins.
Example would be glucose
what is Osmosis
Is the net random movement of water from a region of high water potential to low water potential down a water potential gradient, across a partially permeable membrane.
What is hydrostatic pressure
Pressure created by water in an enclosed system.
The 3 types of solution in osmosis
Hypotonic - high water potential
Isotonic - equal water potential
Hypertonic - low water potential
Osmosis in plant cells
Hypotonic -> turgid
Isotonic -> flaccid
Hypertonic -> plasmolysed
Osmosis in animal cells
Hypotonic-> cytolysis
Isotonic -> normal
Hypertonic -> crenated
What is Active transport and the process.
Movement of substance against a concentration gradient. ATP is required and transport/carrier protein which acts as a pump.
- molecule binds to the receptor which is complementary.
- ATP binds on the inside of the cell. It hydrolysed so it is ADP + P. Phosphate remains bound phosphorylating it.
- energy is used to change shape and phosphates is released and recombined with ADP. Carrier protein returns to original shape.
what is Bulk transport
Another form of active transport bust substances are too large to move through channel or carrier proteins. ATP is needed to move vesicles, change shape of cells and fuse to the cell membrane. There are two types:
Exocytosis
Endocytosis
Example would be hormones
What is exocytosis
When material is passed out of a cell using a vesicle formed at the Golgi apparatus.
- vesicle buds off the Golgi apparatus and moves towards the membrane
- fuses with the membrane and substances are released
What Is endocytosis
The uptake of material into the cell by forming a vesicle with the cell surface membrane. There are two types phagocytosis (movement of solids) pinocytosis (movement of liquids).
Examples of active transport
Potassium entering the root of plants and minerals entering small intestines villi cells
