Anatomy Crossing Cell Membrane Using Cellular Transport

electromechanical gradient

keeping ions where they belong

gradient

-basically a difference

-pressure gradients (pressure differences)

-electromechanical gradients (part electrical/part mechanical)

ATPase pump

exchanges sodium for potassium

-for every three sodium passed out, two potassium come in

osmosis

-movement of water

-jitteriness of liquid molecules is called kinetic energy

energy system

tendency of energy is to flow from areas of high energy to low energy

turgor pressure

inside pressure of cell (also referred to as hydrostatic pressure)

osmolarity

concentration of all dissolved solutes in a compartment per liter of solution

tonicity

describes water concentration between two compartments or the measurement of the effective osmotic pressure gradient

tonicity vs. osmolarity

-term of comparison b/w two separate compartments

-an absolute number that doesn’t compare itself to osmolarity of compartments separated from it

hypotonic solutions

-more dilute and have lower osmolarity

-cause water to rush into cell, bursting it

isotonic solutions

-outside the cell have same osmolarity as inside the cell

-have water entering and leaving cell equally, so no change

hypertonic solutions

-more concentrated and have higher osmolarity compared to inside of cell

-cause water to rush out, shrinking in

osmotic pressure

-pressure of enclosed biological space

-drives water across membrane

hydrostatic pressure

-opposite to osmotic pressure

-more what we see every day ex: water hose squirting out rapidly with high pressure or dripping with low pressure

diffusion

-natural physical process

-travel of molecules from high to low concentration

-requires no energy b/c its a downhill motion

cell membrane

-barrier

-nonpolar molecules that are hydrophobic cab cross it b/c membrane is hydrophobic

-polar hydrophillic molecules can not cross

facilitated difussion

-diffusion with help from high to low concentration

-requires no energy

-passive transport across membrane with help of proteins: channel and carrier proteins

channel proteins

Channels: where ions and molecules pass

-if open all the time called non-gated channel proteins

-gated channel proteins stay closed unless signal telling them to open

-one channel protein is called aquaporin which forms pores in membrane and facilitates transport of water b/w cells

carrier proteins

-need to bind to the protein first to carry across membrane

-built to bind, morph in a different shape, and change shape as it spits out the molecule

-direction is always from a high to low concentration

active transport

-also involves a carrier protein

-carries molecules in opposite direction of concentration gradient which requires energy

-primary active transport: ATP is used

-secondary active transport: uses an electromechanical gradient

ATP

-has 3 phosphate molecules and when one is removed, it makes ADP

-the metabolic processes that use ATP convert it back to ADP and recycled in mitochondria to make ATP energy

sodium-potassium exchange pump

-sodium and potassium ions need to travel from one side to other of membrane against the gradient and need a pump to do so

-called ATPase pump b/c it needs ATP energy

-uses enzyme called ATPase that takes ATP and turns it into ADP

uniport

-means one direction

-molecule goes in one direction only through use of carrier protein

symporter secondary transport

two molecules going through the carrier protein in the same direction

antiport transport

draws another molecule against its concentration gradient in the opposite direction

endocytosis

-transports proteins using vesicles

-involves cell eating (phagocytosis) and cell drinking (pinocytosis)

-process w/o needing proteins but rather uses caveolae: make caves, collect molecules to bring them inside cell

exocytosis

reverse of endocytosis where vesicles are made inside the cell and sent outside