2.4.12~specialised cells Flashcards
what are the specilised cells for diffusion
-root hair cells
-epithelial cells
what are root hair cells adapted for
absorption of water and mineral ions form soil
how is shape of root hair cell specilised
increases surface area so rate of water uptake by osmosis is greater
how is root hair cell cell wall specilised
thinner than other plant cells so have a shorter diffusion distance
root hair cell vacuole
permanent vacuole containing cell sap which is more concentrated than soil water –> ensures a higher water potential gradient is maintained
how are epithelial cells adapted (microvilli)
have microvilli (highly folded sections of cell membrane) which increases the cells surface area so the rate of diffusion of products of digestion is greater
epithelial cells adaptation (blood supply)
has a constant blood supply which continually transports the products of digestion away from epithelial cells. this maintains a high concentration gradient across epithelial cells exchange surface
what cells are specilised fro facilitated diffusion
neurons, muscle cells and some kidney cells
how are kidney cells adapted for facilitated diffusion
-cell membranes that contain a very high number of aquaporins
-aquaporins are special channel proteins that allow the facilitated diffusion of water through cell membranes
-the aquaporins allow these kidney cells to reabsorb water, stopping it from being unnecessarily excreted from the body
how are neurons and muscle cells adapted for facilitated diffusion
-they have membranes that contain channel proteins for sodium, potassium and calcium ions
-the opening and closing of these channel proteins as well as the number of these channel proteins, plays an important tole in speed of electrical transmission, both along membranes of neurons and in muscle cells
