Bio Test 2 (Lecture 14 - Cell Transport)

what does the cell membrane do

***made of the phospholipid bilayer

-keeps internal and external environments separate

-controls what enters and exits the cell

-keeps the fluid inside

what are the four parts of the cell membrane

-phospholipids

• (only lets certain things enter and exit)

-proteins

• (helps things move in and out of the cell)

-cholesterols

• (keeps the cell membrane fluid)

-glycolipids/glycoproteins

• (tells the body here the cell belongs)

what is solvent

the substance that things are dissolved into (water)

what is solute

the thing that is being dissolved (salt)

what is a solution

solvent + solute

what is diffusion

movement of a substance from an area of high concentration to low concentration

what is osmisis

diffusion of water from high to low concentration

what can move across the membrane with no energy input

-water

-small fat molecules

-small gas molecules (oxygen, carbon dioxide)

what can’t move across the membrane freely

-ions (they have a charge)

-larger molecules (sugars, amino acids, nucleic acids)

what is facilitated diffusion

(includes passive and active transport)

membrane proteins help molecules move across the membrane from an area of high concentration to an area of low concentration

what is passive transport

-the movement of molecules across a cell membrane from an area of high concentration to an area of low concentration

-passive = "downhill", meaning it does not require cellular energy (ATP)

what is active transport

-the movement of molecules across a cell membrane from an area of low concentration to an area of high concentration

-active = "uphill", meaning it it requires cellular metabolic energy (ATP) and “pumps”

what are vesicles

a smaller phospholipid bilayer used for transportation within the cell

• ex: golgi appartaus or rough ER

what is exocytosis

the process of things leaving the cell by fusing a vesicle with the cell membrane to release material

what is endocytosis

the process of bringing things inside the cell by forming a vesicle