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Cell Physiology

The structure of the cell surface membrane;

The phospholipid bilayer is the basic structure of the cell surface
membrane. There are also cholesterol molecules in among the
hydrocarbon tails. Proteins are attached to the bilayer (extrinsic),
embedded into one layer (intrinsic) or span both layers (intrinsic
and transmembrane).…

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Fluidity is influenced by temperature. The membrane at higher
temperatures is more fluid and less fluid at lower temperatures
as the phospholipid bilayer `freezes' into a `gel' state.
Cholesterol acts as a temperature stability buffer. At high
temperatures, cholesterol provides additional binding forces
and so decreases membrane fluidity. At low…

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Adding water=higher solute potential

Adding salts=lower solute potential

Pressure potential this is the effect of pressure on the solution.

A turgid cell results in higher pressure on the cell
wall. A plasmolysed cell results in lower pressure on
the cell wall (=0). Pressure potential is usually a
positive value.


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The vacuole pushes against the cell wall.

Why does the plant cell not burst?

Cell wall for protection.

If water leaves a plant cell, it becomes plasmolysed-what does this

The cell membrane shrinks away from the cell wall.

When does incipient plasmolysis occur?

Water potential inside the cell=water potential…

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The substrate binds to carrier proteins
The protein changes shape, releasing the substance on the other
side of the membrane.

What would an increase in temperature do to the rate of active

Increase-more energy would be available for the carriers to change

What organelle is…


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