Active Transport

active trans

cell uss bond energy from ATP to move solutes across mem

active trans mechanisms

• primary active and secondary

• → solute “pumps” (proteins) that move ions uphill/against concentration gradient

  • → low to high

primary active

energy directly from hydrolysis of ATP

→ selective

→ hydrolysis of ATP= phosphorylation of tarns protein to change configuration so pump bound solute againts concentration gradient (ATP powers the pump → pump changes shape → molecule is moved against its gradient.)

primary active trans

why sodium potassium pump essential

concentration differences essential for cell to maitain fluid volume and for excitable cells

sodium potassium pump 

• primary active ver important 

• every ATP pumps 3 Na OUT and 2 K IN 

• ‘high K inside high Na outside 

  • unequal causes electrical charge 

sodium potassium pump

secondary active

• cannot happen wt out primary

• ATP used in primary to set up ability to do secondary

  • → NOT USED DIRECTLY

what energy in secondary 

energy stored in form of an ion concentration (usually Na) to drive other substances against gradient 

• AKA co trans bc 2 substances cross mem at the same time 

• 1. symporters 

  • 2. antiporters 

antiport

Na in, down gradient

Ca out, against gradient

• opposite directions

symport

glucose in, along gradient

Na in, against gradient

• same direction

secondary active 

mem pump of trans protein allows cell to be

selective abt what allows cross mem

vesicular trans

• large particles macromolecules fluids

• energized by ATP

  • endocytosis, exocytosis

vesicle 

small membranous sac formed by budding off from existing mem

exocytosis

• mem enclosed structures called secretory vesicles that form inside the cell fuse wt the plasma me and release their contents into the ECF

  • hormone secretion, neurotransmitter release, mucous secretion, ejection of wastes

exocytosis

endocytosis

cell eating

1. Phagocytosis

2. pinocytosis

3. receptor-mediated endocytosis

• surface area of plasma mem remains constant bc plasma mem removed by endocytosis is replaced by that gained during exocytosis

phagocytosis

reaching out adn grabbind smt solid

• reaching= dathern protein

• solid= bacterium or particle

  • pinch

phagocytosis 

pinocytosis

forms a pit

• liquids

pincytosis

receptor mediated 

grabs substances 

• “Y” 

receptor mediated