Cell membranes Flashcards
What is proteins role in the cell membrane?
To move large or charged molecules across the membrane
What is cholesterols role in the cell membrane?
Stability and fluidity
What are carbohydrates role in the cell membrane?
Makes the cell its attached to recognisable to things outside the cell
What is the phospholipid bilayers role in the cell membrane?
It provides a barrier between the cytoplasm and outside the cell
What is a hypertonic solution?
- Low H2O outside
- H20 flows out of the cell, pressure drops
- Cell becomes dehydrated and shrivels up in animals, vacuole shrinks in plants
What is a hypotonic solution?
- High H2O outside
- H2O flows into cells
- Pressure builds up, cells burst in animals, in plants, they become turgid due to cell wall
What is an isotonic solution?
- No change in cell
- H2O moves in and out at the same rate
- the H2O concentration outside the cell is equal to the H2O concentration inside the cell
What is diffusion?
Movement of a solute from a high concentration to low concentration.
What is osmosis?
Diffusion involving water passing through a selectively permeable membrane. Moving from a high to low concentration
What molecules can diffuse across the membrane in diffusion?
Oxygen and carbon dioxide
What is active transport?
- Involves channel proteins and a source of energy/ ATP
- Requires ATP to move materials across the cell membrane against the concentration gradient
What is facilitated diffusion?
Substances are helped across the cell membrane via passive channel molecules. Moves from low to high concentration
What substances move across the membrane via facilitated diffusion?
larger molecules like sugar, amino acid, nucleotides, charged ions and nutrients
What does semipermeable mean?
Only lets some things pass and not others
What are phospholipids?
bulk of membrane, creates barrier between intracellular and extracellular fluid
