Unit 5 CHATGPT Flashcards
(13 cards)
What is the fluid mosaic model?
It describes the plasma membrane as a dynamic structure with proteins embedded in a phospholipid bilayer, allowing lateral movement (fluid) and diverse protein components (mosaic).
What does selectively permeable mean?
It means the membrane allows some substances to pass while blocking others, helping maintain internal cell conditions.
Describe the structure of a phospholipid and its role in the membrane.
A phospholipid has a hydrophilic head and hydrophobic tails. They form a bilayer with heads facing water and tails inward, forming a semi-permeable barrier.
Define hydrophilic and hydrophobic.
Hydrophilic means water-attracting, while hydrophobic means water-repelling.
What are integral and peripheral proteins?
Integral proteins span the membrane and aid in transport and signaling; peripheral proteins attach to membrane surfaces and assist in support and communication.
What is passive transport?
Movement of substances across membranes without energy input. Includes simple diffusion, facilitated diffusion, and osmosis.
What is active transport?
Movement of substances against concentration gradients using energy (ATP), e.g., sodium-potassium pump.
Define concentration and electrochemical gradient.
Concentration gradient is a difference in substance concentration; electrochemical gradient combines concentration and charge differences across membranes.
Compare simple diffusion, facilitated diffusion, and osmosis.
Simple diffusion moves small molecules directly through membranes; facilitated uses transport proteins; osmosis is water movement across membranes.
What is primary active transport?
Transport that uses ATP directly to move substances against their gradient, like the sodium-potassium pump.
What is secondary active transport?
Uses energy from one substance moving down its gradient to move another against its gradient.
Define endocytosis and give an example.
Cell engulfs substances in vesicles, e.g., phagocytosis of bacteria by white blood cells.
Define exocytosis and give an example.
Vesicles fuse with the membrane to release substances, e.g., neurotransmitter release from neurons.
