Movement into and out of cells Flashcards iGCSE Biology

[q] How does Active transport works?

[a] Active transport works by using carrier proteins embedded in the cell membrane to pick up specific molecules and take them through the cell membrane against their concentration gradient:

[q] What is Diffusion?

[a] The net movement of particles from a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of their random movement is called Diffusion.

[q] What are the Functions of Active transport?

[a]

• Uptake of glucose by epithelial cells in the villi of the small intestine and by kidney tubules in the nephron.
• Uptake of ions from soil water by root hair cells in plants.

[q] What is Osmosis?

[a] The net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential(concentrated solution), through a partially permeable membrane is called Osmosis.

[q] How are Plant cells supported?

[a] The turgor pressure within cells exerted by water pressure in vacuole. Turgor pressure causes cell membrane to push against an inelastic cell wall.

[q] State 4 factors of diffusion

[a]

• Temperature;
• Surface area;
• Concentration (gradient) / water potential;
• Size of molecule;
• Distance across membrane / permeability (of membrane);
• Pressure;
• (Number of) protein, channels / pumps / AW;
• Energy / number of mitochondria;

[q] What is this effect called?

[a] Turgidity

[q] What is this effect called?

[a] Plasmolysis

[q] Plasmolysis is the result of?

[a] Loss of water from the plant cell. There is higher water potential in the cell and lower water potential outside the cell. Water diffuses out of vacuole by osmosis.