Week 12 / Cellular Process 2 [optional] Flashcards
Q: What is the general description of passive processes in cellular transport?
A: Passive processes move substances down a concentration gradient until equilibrium is reached and do not require cellular energy in the form of ATP.
Q: What is simple diffusion?
A: Simple diffusion is the movement of a substance by kinetic energy down a concentration gradient until equilibrium is reached, without the need for energy.
Q: What is osmosis?
A: Osmosis is the passive movement of water molecules across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.
Q: What is facilitated diffusion?
A: Facilitated diffusion is the passive movement of a substance down its concentration gradient, aided by ion channels or membrane transport proteins.
Q: What is the general description of active processes in cellular transport?
A: Active processes move substances against a concentration gradient and require cellular energy in the form of ATP.
Q: What is active transport?
A: Active transport is the movement of substances across the membrane against their concentration gradient, aided by membrane proteins that act as pumps using energy from ATP.
Q: What is transport in vesicles?
A: Transport in vesicles involves the movement of substances into or out of a cell in vesicles that bud from or fuse with the plasma membrane, requiring energy from ATP.
Q: What is endocytosis?
A: Endocytosis is the movement of substances into a cell in vesicles, which can involve “cell eating” (phagocytosis) or “cell drinking” (bulk-phase endocytosis).
Q: What is phagocytosis?
A: Phagocytosis, also known as “cell eating,” is the movement of solid particles into a cell after pseudopods engulf them.
Q: What is bulk-phase endocytosis?
A: Bulk-phase endocytosis, or “cell drinking,” is the movement of extracellular fluid into a cell by the infolding of the plasma membrane.
Q: What is exocytosis?
A: Exocytosis is the movement of substances out of a cell in secretory vesicles that fuse with the plasma membrane and release their contents into the extracellular fluid.
Q: What substances are transported by each process?
Simple diffusion: Lipid-soluble molecules like oxygen, carbon dioxide, and fatty acids.
Facilitated diffusion: Polar molecules such as water and urea.
Active transport: Ions such as K+, Na+, Ca²+, and other ions like glucose and some vitamins.
Endocytosis: Bacteria, viruses, and dead or aged cells.
Exocytosis: Neurotransmitters, hormones, and digestive enzymes.
