chapter 3 study guide Flashcards
define cell
the smallest unit of life that is responsible for all of life’s processes
name and describe the composition of extracellular materials
- a general term for the proteins and polysaccharides that are secreted by some cells, act as connective material
- components are collagen, proteoglycans, bronectin, and laminin
three major regions of a generalized cell
plasma membrane, cytoplasm, and nucleus
plasma membrane
the outer covering of the cell that encloses the cytoplasm
cytoplasm
the jelly like matrix within the cell that contains various organelles
nucleus
round and usually centrally placed structure that controls the various activities of the cell
the chemical composition of the cell membrane
plasma membrane, phospholipids, cholesterol
plasma membrane
composed of phospholipids, cholesterol and proteins that provide a barrier between the external environment of the cell, regulate molecules that enter the cell, and allow communication between cells via protein receptors
phospholipids
have a polar hydrophilic head and non- polar hydrophobic tails, major component in cellular membranes that allow different materials in and out of the cell
relate the cell membrane structure to passive transport mechanisms
- phospholipid bilayer allows small, non-polar molecules to diffuse freely
- protein channels allow for the passive transport of larger and charged molecules
- channel proteins- forms channels that allow ions to move down their concentration gradient through the membrane (facilitated diffusion)
- carrier proteins bind to molecules on one side of the membrane and transport them through, large molecules
simple diffusion
structure of the lipid bilayer allows small, non-polar molecules to pass through the cell membrane, down their concentration gradient
facilitated diffusion
- uses channel and carrier proteins
- channel proteins are less selective and don’t let molecules through based on size and charge
- carrier proteins are very selective and only let one particular type of molecule to cross
osmosis
diffusion of water through a semipermeable membrane down its concentration gradient. if a membrane is permeable to water but not to a solute, water will equalize its own concentration by diffusing to the side of lower water concentration
difference between primary and secondary active transport
- primary active transport uses energy directly from ATP to move molecules, uses a pump
- secondary active transport uses energy stored in the electrochemical gradient to transport a molecule
endocytosis
when a cell envelopes extracellular materials using it’s cell membrane (phagocytosis and pinocytosis)
