Compartmentalisation Flashcards
What are the roles of compartmentalisation?
- Keeping important things outside and bad stuff on the outside
- Segregating incompatible biological processes
- Providing specialised microenvironments
- Facilitating the formation of gradients
In order to facilitate the formation of gradients what property must a lipid bilayer have?
It must be selectively permeable
Give 3 examples where compartmentalisation plays a key role in energy generation
- Mitochondria
- Chloroplasts
- Purple Photosynthetic bacteria
Which way do ATP synthase stick out in mitochondria?
Inwards into the matrix
Which way do ATP synthase stick out in chloroplasts?
Outwards into the stroma
Which way do ATP synthase stick out in purple photosynthetic bacteria?
Gace inwards into the cytoplasm
What is associated with a concentration gradient of any chemical species?
A Gibbs free energy difference
What affects whether the ΔG for a concentration gradient has a + or - sign?
The direction of transport
What is ΔG(in-out) ?
The energy required to move 1 moled of substance A from the outside to the inside
If [A] inside the cell is smaller than [A] outside the cell will ΔG(in-out) be spontaneous?
Yes as ΔG will be negative
If [A] inside the cell is greater than [A] outside the cell will ΔG(in-out) be spontaneous?
No, as ΔG will be positive
What is the effect on ΔG of changing the direction of movement?
It changes the sign of ΔG
What does the production and maintenance of a gradient of ions between 2 compartments often require?
A source of energy
Give some uses of Ion Gradients
- Energy transduction
- Used to power transport
- Na+/K+ gradients responsible for nerve impulses
- Trigger intracellular responses (K+ and Ca2+)
- Some bacteria use ions (Na+) to power ATP synthase
What parts of the protonmotive force does E.Coli use to power lactose uptake?
Both charge difference and [H+]
