An ion gradient is a concentration gradient of ions, it can be called an electrochemical potential gradient of ions across membranes. Ionophores are important for ion gradients.
The movement of solutes along a concentration gradient is common in many biological processes. For a more elaborated discussion, read the Tutorial in Cell Biology where various ways substances pass through a cell membrane are described.
An Ion gradient has potential energy and can be used to power chemical reactions when the ions pass through a channel (red).
The diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential.
electrogenic pump ...
concentration gradient The difference in concentration in two parts of a system.
A hydrogen ion gradient is also used to produce ATP in the chloroplast (diagram below). In this case, sunlight provides energy to pump hydrogen ions into the thylakoid.
a concentration gradient (20/0.1 = 200) and a
electrostatic gradient (moving a negative charge against a voltage of − 70 mV).
ΔG = (R)(T) x ln(20/0.1) + (z)(F)(Vm) ...
Remind them of the good Îol selectively permeable membrane (the phospholipid bilayer) and how the hydrophobic tails are responsible for making the ion gradient possible. Maintaining this ion gradient is essential to life. 3.
Some of these proteins can move materials across the membrane only when assisted by the concentration gradient, a type of carrier-assisted transport known as facilitated diffusion.
Like many of the other coordinate genes, bicoid encodes a transcription factor; thus, there is a concentration gradient of a transcription factor.
Many times, proteins have to work against a concentration gradient. That term means they are pumping something (usually ions) from areas of lower to higher concentration. This happens a lot in neurons.
Water moves down its concentration gradient
When pressure is equal on both sites net flow ceases (equilibrium)
The pressure is said to be hydrostatic (water-stopping)
Water potential ...
Active transport The transport of an ion or a molecule against a concentration gradient, where DG for the transported species is positive; the process must be coupled to an input of free energy from a source such as ATP, ...
Simple diffusion can only move material in the direction of a concentration gradient; facilitated diffusion moves materials with and against a concentration gradient.
C.
active transport Transport of molecules against a concentration gradient (from regions of low concentration to regions of high concentration) with the aid of proteins in the cell membrane and energy from ATP. PICTURE ...
Movement of a molecule through a membrane against its concentration gradient, using a carrier protein and energy from ATP
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ...
Phosphorylation of ADP to ATP occurring when protons that are following a concentration gradient contact ATP synthase.
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passive transport (facilitated diffusion) - movement of a molecule across a membrane down its concentration gradient
peripheral membrane proteins-proteins that can be released from the membrane ...
energy-expanding process in which cells transport materials across the cell membrane against a concentration gradient.
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Energy in the form of ATP is required when the cell is pumping molecules in or out against the concentration gradient. This is called active transport.
 See also: Concentration gradient, Trans, Membrane, Cell, Protein
  
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