2.1.5 Biological Membranes – Active Transport Flashcards
(13 cards)
What does the term active transport mean?
The movement of substances against the concentration gradient (from a lower concentration to a higher concentration) through carrier proteins and with the use of energy in the form of ATP
Why is it called active transport?
It requires energy.
What types of substances are moved by active transport?
Substances that are in lower concentration outside the cell than inside the cell.
What is bulk transport?
The movement of large quantities of substances across the membrane, using energy/ATP.
What does the term endocytosis mean?
Bulk transport of molecules into a cell.
What are the two types of endocytosis?
Phagocytosis
Pinocytosis
Describe the process of endocytosis.
The cell surface membrane invaginates and surrounds the substance on the outside of the cell. A vesicle is formed containing the substance and pinches off from the cell surface membrane into the cell.
What does the term phagocytosis mean?
The intake of solid matter by endocytosis.
What does the term pinocytosis mean?
When cells ingest liquids by endocytosis.
What does the term exocytosis mean?
Bulk transport of molecules out of a cell.
Describe the process of exocytosis.
The substance is transported in a vesicle to the cell surface membrane. The vesicle fuses with the cell surface membrane and the substance is released out of the cell.
Give two reasons why ATP is needed in the process of bulk transport.
To provide the energy to form the vesicles and to move them using motor proteins along the cytoskeleton.
Large molecules such as enzymes, hormones and whole cells such as bacteria are too large to move into or out of the cell via carrier or channel proteins. What method do they use instead?
Bulk transport
