Key Area 2 - Transport Across Cell Membranes Flashcards
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.
