Chapter 6.4 Flashcards
(21 cards)
What is endocytosis?
Endocytosis is a general term for processes that bring small molecules, macromolecules, large particles, and small cells into eukaryotic cells.
What are the three types of endocytosis?
The three types of endocytosis are phagocytosis, pinocytosis, and receptor-mediated endocytosis.
What happens during phagocytosis?
In phagocytosis, part of the cell membrane engulfs large particles or entire cells, forming a food vacuole or phagosome that usually fuses with a lysosome for digestion.
What is pinocytosis?
Pinocytosis is a process where vesicles form to bring fluids and dissolved substances into the cell.
How does pinocytosis operate in the endothelium?
Pinocytosis occurs constantly in the endothelium, allowing cells to rapidly acquire fluids and dissolved solutes from the blood.
What characterizes receptor-mediated endocytosis?
In receptor-mediated endocytosis, molecules at the cell surface recognize and trigger the uptake of specific materials.
What is receptor-mediated endocytosis?
Receptor-mediated endocytosis is a highly specific process used by animal cells to capture specific macromolecules from the cell’s environment.
What role do receptor proteins play in receptor-mediated endocytosis?
Receptor proteins are integral membrane proteins that bind to specific molecules within the cell or in the cell’s external environment.
Where are receptors located in the cell during receptor-mediated endocytosis?
Receptors are located at particular regions on the extracellular surface of the cell membrane, known as coated pits.
What are coated pits?
Coated pits are membrane regions that form slight depressions on the extracellular surface of the cell membrane.
What is primary active transport?
Primary active transport is the process by which ions or molecules are moved across a cell membrane against their concentration gradient using energy.
Example: The Na+-K+ pump is a type of primary active transport.
What does the Na+-K+ pump do?
The Na+-K+ pump moves sodium ions (Na+) out of the cell and potassium ions (K+) into the cell.
This process is essential for maintaining the concentration gradient of Na+.
What energy source does the Na+-K+ pump use?
The Na+-K+ pump uses the energy from ATP hydrolysis to function.
ATP hydrolysis provides the necessary energy for the active transport process.
What is the result of the Na+-K+ pump’s action?
The action of the Na+-K+ pump establishes a concentration gradient of sodium ions (Na+) across the cell membrane.
What is secondary active transport?
It is a process where one substance moves against its concentration gradient, driven by another substance moving with its concentration gradient.
How does sodium (Na+) contribute to glucose transport?
Na+, moving with the concentration gradient established by the Na+-K+ pump, drives the transport of glucose against its concentration gradient.
What are the three types of proteins for active transport?
The three types of proteins for active transport are symporters, antiporters, and coupled transporters.
What is the function of a symporter?
A symporter moves two substances in the same direction.
Example: A symporter in the cells that line the intestine must bind Na in addition to an amino acid to absorb amino acids from the intestine.
What is the function of an antiporter?
An antiporter moves two substances in opposite directions, one into the cell and the other out of the cell.
Example: Many cells have a sodium-potassium pump that moves Na out of the cell and K into it.
What are symporters and antiporters also known as?
Symporters and antiporters are also known as coupled transporters because they move two substances at once.
How is transport directional in active transport?
In active transport, transport is directional, meaning substances are moved against their concentration gradients.
