Unit 1 Topic 2 - Transport Across Membranes Flashcards
What are cell membranes made up of?
Proteins and phospholipids
Name 3 ways substances can cross cell membranes
• diffusion(passive transport)
• osmosis (passive transport)
• active transport
What molecules can pass freely across membranes?
• small molecules
• oxygen
• water
• carbon dioxide
What molecules can not pass freely across membranes?
• large molecules
• glucose
What is passive transport ?
transport that doesn’t require energy, molecules pass from a high concentration to a low concentration
What is osmosis?
the movement if water molecules from an area of low water concentration to an area of high water concentration
What is diffusion?
when molecules move down the concentration gradient from a higher concentration to a lower concentration
In a pure water solution a plant cell will…
Become turgid (swell up)
In a weak sugar/salt solution plant cells will…
Not change
In a strong sugar/salt solution a plant cell will…
become plasmolised (vacuole and cytoplasm shrink)
In pure water solution animal cells will…
Burst
In a weak salt solution animal cells will…
Not change
In a strong salt solution animal cells will…
Shrivel up
