Active Transport Flashcards
what molecules are often transported in organisms via active transport?
ions
what is the definition of active transport?
the movement of substances against their concentration gradient (from low to high) across a cell membrane, using ATP and carrier proteins
how is the ATP necessary produced?
during aerobic respiration in the mitochondria
how are substances transported using carrier proteins?
carrier proteins of specific shape are required to transport a substance of complimentary shape against the concentration gradient
why is active transport ATP dependent?
the carrier protein changes shape, which is ATP dependent, as it transports substances in one direction
what is an example of active transport?
root hair cells use active transport to absorb minerals from the soil
what is cytosis?
mass movement of substances (energy dependent
what is ATP?
energy currency
how can substances enter and leave cells?
through cytosis
how is cytosis possible?
due to the fluid nature of the cell surface membrane
what does cytosis require?
energy
why does cytosis require energy?
as it involves breaking open the bilayer and then reforming it
what are the two types of cytosis?
endocytosis (in)
exocytosis (out)
what happens to the membrane always after cytosis?
it always reforms, due to the fluid nature of phospholipids IMPORTANT
what is endocytosis?
when substances are moved into a cell
what is an example of endocytosis?
WBC engulfing invading pathogens then digest them using enzymes in the lysosome
what are the steps of endocytosis?
- the cell surface membrane infolds (invaginates) round substances outside the cell to form a vesicle
-the vesicle then enter the cell and the membrane reforms
-ATP provides the energy to form vesicles and move them using motor proteins along the cytoskeleton microtubules
what are the two types of endocytosis?
phagocytosis
pinocytosis
what is phagocytosis?
-cell eating
vesicle traps solids (eg bacteria) or food substances to be taken into cells
what is pinocytosis?
-cell drinking
vesicle traps liquid to be taken into cells
how to remember the difference between the two endocytosis’?
pinocytosis
pino grigio —> alcoholic drink
what is exocytosis?
when solid or liquid materials are move out of cells, when vesicles fuse with the cell membrane
what is an example of exocytosis?
-insulin
it’s made in such large quantities, it must be released into the bloodstream by exocytosis
-cell wall materials are exocytosed in plat cells
what are the steps of exocytosis?
-vesicles contain isolated substances
-vesicles move towards the cell surface membrane and fuses with it, enabling the contents of the vesicle to be expelled from the cell
-the membrane then reforms due to the fluid nature of the phospholipid
