Untitled Flashcards Set

What are phospholipids and their structure?

Phospholipids are amphipathic molecules with a polar hydrophilic head (phosphate group) and two nonpolar hydrophobic fatty acid tails.

What is the Fluid Mosaic Model?

The Fluid Mosaic Model describes the plasma membrane as a dynamic structure with lipids and proteins that can move and flow, held together by hydrophobic interactions.

How do cholesterol molecules affect membrane fluidity?

Cholesterol molecules regulate membrane fluidity by restraining the movement of phospholipids at warm temperatures and maintaining fluidity at cool temperatures.

What is selective permeability?

Selective permeability is the ability of the cell membrane to allow certain substances to pass through while blocking others, influenced by the membrane's structure.

What is the difference between passive and active transport?

Passive transport moves molecules from high to low concentration without energy, while active transport moves molecules from low to high concentration and requires energy (ATP).

What are the types of endocytosis?

There are three types of endocytosis: phagocytosis (intake of large particles), pinocytosis (intake of extracellular fluid), and receptor-mediated endocytosis (intake of specific target molecules).

What is osmosis?

Osmosis is the diffusion of free water across a selectively permeable membrane, primarily through aquaporins.

What is tonicity?

Tonicity measures the concentration of solutes inside and outside a cell, affecting the cell's shape depending on whether it's hypertonic, isotonic, or hypotonic.

What is the purpose of aquaporins?

Aquaporins are channel proteins that facilitate the rapid passage of water through the cell membrane.

What does water potential indicate?

Water potential measures the tendency of water to move by osmosis, influenced by solute and pressure potentials.