Cells Flashcards
What is passive transport?
Passive transport is when molecules diffuse from a region of high concentration to a region of lower concentration and does not require energy.
What are the 4 primary types of passive diffusion?
Simple diffusion, facilitated diffusion, filtration, and osmosis.
What is facilitated diffusion?
Facilitated diffusion is when molecules diffuse across a cell membrane with assistance from membrane proteins and carriers.
Examples: large and charged molecule (carbohydrates, amino acids, and ions)
What is simple diffusion?
The simplest form of diffusion is simple diffusion. Molecules diffuse through a semipermeable membrane down their concentration without assistance from transporter proteins.
Examples: oxygen and carbon dioxide
What are transport proteins?
Transport proteins are proteins that move molecules across the membrane within a cell. Transport proteins aid in facilitated diffusion and active diffusion.
Examples: channel proteins, carrier proteins, and sodium potassium pumps
How do channel proteins aid facilitated diffusion?
Channel proteins can aid in facilitated diffusion of substances by forming a hydrophilic passage through the membrane through which polar and charged substance can pass.
What is active transport?
Active transport is when molecules/ions are moved against their concentration gradients from a region with lower concentration to a region with higher concentration which requires energy (ATP)
Protein physically bind to the material during active diffusion
What is endocytosis?
Endocytosis is a cellular process in which substances are brought into the cell by engulfing them in a vesicle. The materials surrounding the membrane are internalized.
Examples: fluids, proteins, and other macromolecules.
What type of transport is endocytosis? What are the two subdivision of endocytosis?
Endocytosis is a form of active transport.
Endocytosis is divided into two subdivisions, pinocytosis and phagocytosis.
What is phagocytosis?
Phagocytosis (the cell eating) is when cells engulf and digest. It is the ingestion of large particles by a large vesicle (phagosome)
Examples: destroys a virus/infected cell often used by the immune system
What is pinocytosis?
Pinocytosis (the cell drinking) is when the cell takes in fluids along with dissolved small molecules. It described the internalization of extracellular fluid and small macromolecules by a small vesicle
Example: absorption of fat droplets
What is receptor mediated endocytosis?
Receptor mediated endocytosis is when receptor proteins on the cell surface are used to capture specific, target molecules. It is a specific process for substances recognized by a cell-surface receptor. A specialized form of Pinocytosis.
Example: The ingestion of cholesterol
What is bulk transport?
Bulk transport is a mode of transport for large quantities of materials and food particles across the membrane.
Bulk transport: phagocytosis, pinocytosis, receptor-mediated endocytosis
What is Exocytosis?
Exocytosis is when cells move large materials from inside the cell to the outside of the cell using small spheres of membranes called vesicles. It is a form of active transport.
Example: secretion of proteins like enzymes
What is the purpose of active diffusion?
The main function of active transport is to pump molecules and ions across membranes against their concentration gradients. Active transport is an energy-requiring process that can transfer substances into, out of, and between cells