ST2. Transport Across Cell Membranes N5 (CB) Flashcards
What do cell membranes consist of?
Phospholipids and proteins
Are cell membranes selectivley permeable?
Yes
Describe passive transport
Passive transport occurs down a concentration gradient and does not require energy
What are some examples of passive transport?
Diffusion and osmosis
What is diffusion?
The movement of molecules down a concentration gradient from a higher to a lower concentration
How do glucose and oxygen diffuse?
Glucose and oxygen diffuse into cells from a higher concentration outside the cell to a lower concentration inside the cell
How does carbon dioxide diffuse?
Carbon dioxide diffuses out of cells from a higher concentration inside the cell to a lower concentration outside the cell
What is osmosis?
The movement of water molecules from a high water concentration to a lower water concentration through a selectively permeable membrane
What is meant by selectively permeable?
membranes can choose to allow or block materials to enter or exit a cell
What happens if an animal cell is placed in a solution with a higher water concentration compared to its cytoplasm?
It will gain water by osmosis, swell up and burst
What happens if an animal cell is placed in a solution with a lower water concentration compared to its cytoplasm?
It will lose water by osmosis and shrink
What happens if a plant cell is placed in a solution with a higher water concentration compared to its cytoplasm?
It will gain water by osmosis and become turgid?
What is meant by turgid?
Swollen and hard
What happens if a plant cell is placed in a solution with a lower water concentration compared to its cytoplasm?
It will lose water by osmosis and become plasmolysed
What plasmosis?
The process of water leaving plant cells, allowing the cytoplasm and plasma membrane to shrink away from the cell wall.
