1.2 Transport across Cell Membranes Flashcards
What is diffusion?
The movement of water molecules down the concentration gradient
From an area of high concentration to an area of low concentration
A passive process that doesn’t require energy
What is osmosis?
The movement of water molecules down the concentration gradient
From an area of high concentration to an area of low concentration
A passive process that doesn’t require energy
What is the cell membrane made of?
Phospholipids
Proteins
What chemicals move by diffusion
In: Oxygen, glucose, and amino acids
Out: Carbon dioxide
What happens to animal cells when they are put in a solution of high water concentration?
They gain water and burst
What happens to animal cells when they are put in a solution of low water concentration?
They lose water and shrink
What happens to plant cells when they are put in a solution of high water concentration?
They gain water and become turgid. They don’t burst because they have a rigid cell wall.
What happens to plant cells when they are put in a solution of low water concentration?
They lose water and become plasmolysed
What is active transport?
The movement of molecules against the concentration gradient
An active process that does require energy
From an area of low concentration to an area of high concentration
Done by the proteins in the cell membrane
What is a key feature of the cell membrane?
It is selectively permeable
