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Transport Across Membranes - Coggle Diagram
Transport Across Membranes
Passive Transport
Channel Proteins
Channel proteins can only do
facilitated diffusion
NO ATP is hydrolysed so it is
passive*
Molecules move down the concentration gradient until equilibrium is reached
Channel proteins can control facilitated diffusion if they are 'gated' (2). The 'gate' can be opened/closed in response to:
chemicals (hormones)
voltage change
Carrier Proteins
Some
carrier protiens
also perform facilitated diffusion
The molecules enter the proteins & caused
conformational change
This moves the molecules into (or out of) the cell
No ATP hydrolysis is required
Active Transport
Active Transport can only be done with carrier proteins (sometimes called pumps)
The conformational change in shape of the carrier protein is powered by ATP hydrolysis i.e. an active process
Bulk Transport
This is where molecules are transported 'en mass' together
It is complete & so
ATP Hydrolysis is required
(but it is not active transport)
In exocytosis, vesicles made from phospholipids fuse with the membrane releasing the contents
Endocytosis is the opposite of exocytosis
Exocytosis:
Endocytosis:
Diffusion
Small non polar molecules such as oxygen & carbon dioxide will diffuse through the membrane as the non-polar fatty acid tails have the same lack of changes as them
Is the movement of liquid/ions from an area of higher concentration to an area of lower concentration until dynamic equilibrium is reached
Osmosis
Movement of free water from an area of its higher concentration to an area of its lower concentration through a partially permeable membrane until a dynamic equilibrium is reached
Water molecules from Hydrogen bonds with polar solutes, putting them into solutions
These adhered molecules are not free to move through the membrane