How substances cross membranes through active processes Flashcards
Define active transport.
The movement of substances against their concentration gradient (from low to high concentration of that substance) across a cell membrane.
Define endocytosis.
The bulk transport of molecules, too large to pass through a cell membrane even via channel or carrier proteins, into the cell.
Define exocytosis.
The bulk transport of molecules, too large to pass through a cell membrane even via channel or carrier proteins, out of the cell.
What two things does active transport require in order to work?
ATP and carrier proteins.
What is the energy provided by in active transport?
The hydrolysis of ATP
Give an example and describe where active transport is used.
Root hair cells. To absorb ions from the soil
If a carrier protein changes its conformation, what has it done?
Changed it’s shape.
Carrier proteins have specific regions, what are these for?
Some combine reversibly to particular solute molecules or ions. One region binds to and allows the hydrolysis of ATP.
What is ATP used for by the carrier proteins?
It helps the carrier protein to change its conformation.
In guard cells ATP made by chloroplasts provides the energy to actively transport what, into where?
Potassium ions into the guard cells.
Give an example of a common carrier protein found in neurones.
Sodium-potassium pump.
Endocytosis is used by _________ to engulf pathogens.
Neutrophil
When phagocytes do the process of endocytosis it has a different name. What is this?
Phagocytosis.
What happens during endocytosis?
A segment of the plasma membrane surrounds and encloses the particle and brings it into the cell, enclosed in a vesicle.
What is it called when cells ingest liquids by endocytosis?
Pinocytosis
