chapter 5- membranes Flashcards
control the flow of substances into and out of a cell
selectively permeable
what are the structures of a cell membrane
phospholipid
proteins
cholesterol
carbohydrate
what do proteins do in a cell membrane?
transport
enzymes
attachment
receptors
junctions
glycoproteins
what does cholesterol do in a cell membrane
-maintains fluidity of membrane
-prevents packing of phospholipids and slows movement
carbohydrate structure of cell membrane
glycolipif and glycoprotein
help substances cross the membrane
transport
speed up chemical reactions
enzymes
_______________ to the extra cellular matrix and to cytoskeleton
attachment
bind to specific molecule
receptors
connections between cells
juntions
cell identity/recognition
glycoproteins
passive transport
no cellular energy required
-movement of substances from high concentration to low concentration
-tendency for particles to spread into open space (in or out of cell)
-no cellular energy required
diffusion
example of diffusion
oxygen into cell
carbon dioxide out of cell
movement of water from high concentration to low concentration across a membrane
- the solution is what’s moving, not the solutes in it
- water goes wherever they are more solutes
osmosis
solution with a solute concentration lower than that of the cell
hypotonic
a solution with a higher solute concentration than that of a cell
hypertonic
solute concentration of environment and of a cell are equal
isotonic solution
what happens to an animal cell placed in solution with higher solute concentration than the cell (hypertonic)
it shrivels
what happens to an animal cell when it is placed in a solution with lower solute concentration thst the cell (hypotonic)
it swells and may burst
what happens to a plant cell when placed in a hypotonic solution with lower solute levels
plant cell is turgid (very firm) and healthy. the cell swells but the pressure of cell wall pushes back and prevents from absorbing too much water and bursting like an animal cell would
what happens when a plant cell is placed in isotonic solution with equal concentration of solutes?
the cell is flaccid (limp) and may wilt
what happens when a plant cell is placed in hypertonic environment and there are higher solute levels outside the cell
the plant cell loses water and cell membrane pulls away from the cell wall and plant can die. (plasmolysis)
-movement of cells against concentration gradient using transport protein
-requires cellular energy
- na+ / k+
active transport
-large products of cell (proteins lipids waste) move out of cell through a transport vesicle
-required cellular energy
exocytosis
bringing larger substances against concentration gradient
endocytosis
-cell eating macromolecule
-enters cell thru a vacuole
phagocytosis
-cell drinking
- liquid enters cell through vesicle
pinocytosis
-specific molecule like a hormone binds to receptor
- enter through a vesicle
receptor mediated
