Active transport Flashcards
What is the definition for active transport?
Transport of ions and molecules against the concentration gradient
Is active transport an active or passive transport?
Active
Where does active transport get its energy from?
The hydrolysis of ATP
Made by the cell in respiration
What happens if respiration is inhibited?
Active transport is inhibited too
E.g. by cyanide poison
What does active transport require?
An intrinsic carrier protein as in facilitated diffusion
Because transport is against the concentration gradient the process requires energy and the carrier acts as a pump
What type of particles can only be actively transported?
Only charged particles
E.g. ions and polar molecules such as glucose that are insoluble in lipid
Explain the process of active transport
Molecule or ions bind to the carrier protein on the outside of the cell membrane
ATP transfers a phosphate group to the carrier protein
Carrier protein changes shape and carries the ion or molecules across the membrane
Molecule or ion is released into the cytoplasm of the cell
Carrier protein returns to its original shape
Give some examples of processes that involve active transport
Mineral uptake by plant roots
Nerve impulse transmission
Why are cells that perform active transport packed with mitochondria?
Mitochondria undergoes aerobic respiration
Produces ATP energy that is needed for active transport
What is endocytosis and exocytosis?
Processes where the cell transports materials in bulk into or out of the cell
Is endocytosis and exocytosis passive or active transport?
Active
What is exocytosis?
Substances may leave the cell having been transported through the cytoplasm in a vesicle, which fuses with the cell membrane
Explain the process of exocytosis
Vesicle is produced in the cytoplasm (e.g. budding of at one end of the Golgi body)
Vesicle migrates to plasma membrane, fuses with it and secretes its contents to the outside of the cell (e.g. secretion of the hormone insulin or digestive enzymes)
What happens to the surface area of the cell after exocytosis?
Increases
Explain the process of endocytosis
Cell membrane folds around the particle
Folding closes off the link to the outside of the cell, so now the particle is fully trapped inside the cell is a vesicle or vacuole
Vesicle is created containing the solid material
Solid material will be destroyed by enzymes
