Flashcards in Transport Across Membranes Deck (20):
Movement of molecules from a high to low concentration down a concentration gradient
What is meant by the term flaccid?
When a cell becomes soft and can no longer support the plant due to water loss
What does the term turgid mean?
the cytoplasm is pushed against the cell wall, making it stretched to the maximum and the vacuole is swollen
What is meant by the term plasmolysed?
When the vacuole shrinks and the cytoplasm is pulled away from cell wall as a result of excessive water loss
What type of solution makes a cell turgid?
A dilute solution
What type of solution makes a cell plasmolysed?
A concentrated solution
What is a selectively permeable membrane?
It controls the entry and exit of certain materials into and out of a cell
What is osmosis?
It is the diffusion of water molecules from a high to a low concentration through a selectively permeable membrane
What is the difference in concentration that exists between two regions, resulting in diffusion?
Movement of molecules from low to high concentration, requiring energy
What is a solution called with a higher water concentration than another solution?
What is a solution called with a lower water concentration than another solution?
What is two solutions with the same water concentration called?
What does the membrane have to let substances pass through?
What are diffusion and osmosis also know as?
What are carrier proteins?
They pick up specific molecules and move them through the cell membrane against the concentration gradient
What do cells need to provide energy to carry out active transport?
What are the types of molecules that the cell membrane is made of?
lipid (fat) and protein
What is the double layer that the lipid molecules form?
Lipid bilayer (makes the membrane strong but flexible)