Practical 6 - Determination of water potential by measuring changes in mass or length Flashcards
What are the different ‘solutions’ that have different water potentials in this experiment?
The cytoplasm and the cell sap of a cell
What separates cytoplasm and cell sap within in a cell?
A selectively permeable membrane
Whats the selectively permeable membrane between cytoplasm and cell sap?
The cell membrane
What is the cell membrane to the cytoplasm and the cell sap within a cell?
The selectively permeable membrane
Within a cell, where will water move through a selectively permeable membrane (between what?)?
Into the solution with the lowest water potential
(Cell sap or cytoplasm)
Which substance do we use which consists of different concentration levels?
Sodium chlorie
What do we use as our tissue sample?
A vegetable - eg potato
Why do we use potato in this experiment?
Contains millions of cells which would have an increase in mass if it gained water by osmosis
+Cells will stretch a small amount = increased length
How many cylinders of tissue do we chop in this experiment + describe these?
15, of equal length
What do we use to remove any periderm from the potato?
A scalpel
Periderm
Skin
Word for the skin on a potato
Periderm
Why do we have to remove the periderm (skin) off of the potato?
Its Suberin makes it waterproof and would prevent osmosis
What may prevent osmosis in the potato?
The periderm (skin), as its Suberin makes it waterproof
How much of each solution do we place in a test tube?
30cm^3
What do we need to do to the potato samples before placing them within the test tubes?
Either…
Measure the length to the nearest mm
Measure the mass to the nearest 0.01g
What do we measure the mass to the nearest?
0.01g