Key Area 2 - Transport Across Cell Membranes Flashcards
(14 cards)
What is the call membrane composed of?
Phospholipids (fat molecules) and proteins
What does concentration gradient mean?
The difference in concentration that exists between a region of high concentration and a region of low concentration
What does diffusion mean?
The movement of molecules from a region of high concentration to a region of low concentration
What does osmosis mean?
Osmosis is the movement of water from an area of high water concentration to an area of low water concentration through a selectively permeable membrane
When a Red Blood Cell is placed in a 5% salt solution, what happens to the cell?
The cell becomes smaller
When a Red Blood Cell is placed in a 1% salt solution, what happens to the cell?
No change
When a Red Blood Cell is placed in distilled water , what happens to the cell?
It gets bigger and bursts
In plant cells, what is it called when the cell has a high water concentration?
Turgid
In plant cells, what is it called if the cell has a lower water concentration?
Plasmolysed
What is a plasmolysed cell? (Plant)
When the cell membrane and contents have pulled away from the cell wall.
What is a turgid cell? (Plant)
When the cell membrane and contents are pushed firmly against the cell wall.
What is active transport?
The movement of molecules and ions across a membrane, from a region of low concentration to a region of high concentration (i.e. Against the concentration gradient)
Which cells must use active transport?
Cells that keep a higher concentration of solute molecules, or ions, within the cell than is present outside.
Cells that use active transport have a larger number of…
Mitochondria because active transport requires energy input to occur.
