Chapter 7

Hydrophobic tail +hydrophilic head (ex. phospholipids)

A membrane is a fluid structure with a “mosaic” of various proteins embedded in it

Penetrate hydrohobic interior

Span across membrane

Ability of cell to distinguish nearby cells from each other (important for organizing cell tissues + rejecting foreign cells)Facilitates passage of water through membrane

Carbs covalently bodned to lipids

Carbs covalently bonded to proteins

Cell membrane allows some substances easier entrance than others

Have a hydrophilic channel that can be used as a tunnel through membrane

Facilitates passage of water through membrane

Hold passengers + change shape to carry across membrane

Selective of substances they carry (important for selective permeability)

Movement of particles of any susbtance so that they spread out into available space (spontaneous + follows concetration gradient)

Substance moves from more concetrated area to less concetrated area

Diffusion of substance across membrane requiring no energy

Diffusion of free water across a selectively permeable membrane

Ability of surrounding solution to cause a cell to gain or lose water

Causes no net movement of water across membrane (same amount of water)

More nonpenetrating solutes, more tonicity (more water)

Less nonpenetrating solutes, less tonicity (less water)

Control of solute concetrations and water

In hypotonic solutions

In isotomic solutions because no water movement occurs

Occurs in hypertonic solutions - plant cell shrivels and dies

Polar molecules and ions diffuse passively with transport proteins

Channel proteins that transpor ions - can function as gated channels (open or close in response to a stimulus)

Can move solutes against the concetration gradient - from low to high concetration

Voltage (electrical porteintial energy) across a membrane

The chemical and electrical forces that power the diffusion of ions across a membrane = ions diffuse along electrochemical gradient

Transport protein that generates voltage across a membrane

Transport protein combines "downhill" diffusion of solute with "uphill" transport of another substance against its concetration gradient

Secretion of certain molecules from cell by the fusion of vessicles with plasma membrane

Cell takes in molecules and particulate matter by forming new vesicles from plasma membrane

Transport
Enzymatic activity
Signal transduction
Cell-cell recognition
Intercellular joining
Attachment to the cytoskeleton and extracellular matrix (ECM)