The Cell Membrane Flashcards
cell membrane?
extremely pliable structure composed of back-to-back phospholipds (a bilayer)
- phosphate heads (hydrophillic) and 2 fatty accid tails (hydrophobic)
what does amphipathic mean?
molecule that contains hydrophilic and hydrophobic regions
integral protein
protein embedded in membrane
channel protein
inegral protein that allows specific materials (like ions) to pass in or out of cell
receptor
recognition protein that can selectively bind a specific molecule outside the cell
ligand
molecule that binds to and activates a receptor
glycoprotein
protein that has carbohydrate molecules attatched that extend into the EC matrix
glycocalyx
- fuzzy looking coating around the cell formed by glycoproteins and other carbs attatched onto the cell wall
- roles: has molecules that allow cell to bind to another cell, receptors for hormones, enzymes to break down nutrients
peripheral proteins
inner or outer surface of lipid bilayer but can attatch to surface of entegral protein
- perform function for cell like: act as digestive enzymes
selective permeability
allows only substances meeting specific criteria to pass through unaided
what can pass through cell mem?
- small nonpolar materials
- other lipids, oxygen and CO2 and alcohol
what needs help to go through cell mem?
water-soluble materials
- glucose
- amino acids
- electrolytes
polar molecules
- unequal amounts of electrons (singles and ready to mingle thats why theyre on the outside)
- likes water (like a polar bear)
- heads of phospholipids
nonpolar molecules
- equal pairings of electrons
- tails of phospholipids
simple diffusion
- passive transport
- moves with flow
- high conc to low conc
- no atp required
facilitated diffusion
- passive
- high to low conc
- with help of transport proteins
ATP
adenine triphosphate
endocytosis
- in
vesicles tak into the cell - phagocytosis: large particles are ingested: surround and eat
- receptor-mediated endyocytosis: process that allows cells to absorb substances from outside the cell USING cell receptors
- pinocytosis: ECF and solutes are taken into the cell via small vesicles
Exocytosis
- moving outward/ exit
- gets rid of waste
concentration gradient
difference in concentration of substance across a space
diffusion
movement of high conc to lower conc
where does O2 typically diffuse? why?
into cells bc its more conc outside of them
where does CO2 typically diffuse?
out of cells bc its more conc outside
faciliated diffusion
diffusion process used for substances that cant cross lipid bilayer due to their size, charge or polarity
osmosis
diffusion of water through a semipermeable membrane
isotonic
two solutions that have same conc of solutes (equal tension)
hypertonic
higher conc of solutes than other solution
- cell shrivesl as ater leaves cell via osmosis
hypotonic
solution that has lower conc of solutes than other solution
- will take on too much water and swell at risk of bursting
types of active transport
- require pumps
- require atp
what is the Na/K pump
- found in membranes of many types of cells
- abundant in nerve cells
electrical gradient
difference in electrical charge across a space
- inside of negatively-charged relative to the outside
- maintained bv the na/k pumps move 3 + out and 2K+ in for each ATP molecule used
symporters
secondary active transporters that move 2 substances in the same direction
antiporters
secondary active transport systems that transport substances in opposite directions
exocytosis
- taking ‘out of the cell’
- ## process of cell exporting material using vesicular transport
