cell transport, membrane and experiments Flashcards
passive transport
- movement of molecules without needing energy
- includes: simple diffusion, facilitated diffusion and osmosis
simple diffusion: through the lipid bilayer
facilitated diffusion: through channel and carrier proteins
osmosis: movement of water molecules across a membrane from a high concentration to a low concentration
3 ways passive transport occurs
- diffusion through lipid bilayer
- facilitated diffusion (through channel, through carrier)
diffusion through lipid bilayer
- allows free passage of some molecules
- straight through membrane
diffusion through channel
- molecules transported through central core
- e.g. H2O
- channel protein
open: are open all the time
gated: they open and close under certain conditions - like a conveyer belt
diffusion through carrier
- molecules attaches to the protein membrane
- will change shape to transport molecule
- suck in sneeze out mechanism
- carrier protein
- carries molecule across the cell membrane
active transport
- moves substances against concentration gradient
- low to high (up hill)
- requires energy
type of active transport
vesicular transport
- endocytosis
- exocytosis
endocytosis
- into the cell
- membrane folds around the particle (completely enclosed)
- vesicle suspends into cell cytoplasm
pinocytosis - taking in liquid
phagocytosis - taking in solids
exocytosis
- out of the cell
- vesicle forms inside the cell
- migrates to the cell membrane and fuses
- contents of vesicle then pushes out
cell membrane
- controls movement of materials into and out of the cell
- fluid mosaic model
- forms the boundary between the internal environment of the cell and the external environment
- selectively permeable
fluid mosaic model
- double layer of phospholipids
- mosaics made of proteins, glycoproteins, glycolipids and cholesterol
protein
- act as a carrier and receptor cities
- may control the movement of specific molecules into and out of the cell
- includes: channel protein, carrier protein, and receptor protein
glycolipids
act as a surface receptor and stabilize the membrane
- squares above the membrane
- hydrophilic tails inside the membrane
glycoprotein
- play an important role in cellular recognition and immune response
- within the membrane and has things coming out the top
cholesterol
- disturbs the closely packing of the phospholipids and regulates membrane fluidity
- hexagons within the membrane
receptor protein
- lock and key model
- specific to certain substances
internal environment
- cell membrane regulates the internal environment
- chemical reactions including respiration and photosynthesis happen here
- enzymes can perform their tasks
- toxic waste producers are removed to ensure they do not with chemical reactions in the cytoplasm
phospholipids
- water proof barrier
- phosphate head (hydrophilic)
- 2 fatty acid tails (hydrophobic)
- arranged as a bilayer
osmotic pressure
- the pressure created by the water moving across a membrane
- the more water the higher the osmotic pressure
hypertonic
high solvent outside the cells, water moves outwards, cell shrinks
hypotonic
low solvent outside the cell, water moves inwards, cell enlarges
isotonic
equal amounts of solvent and water
- cell stays the same
- numbers coming in are equal to the numbers going out
osmosis in animals
- shape of red blood cells is designs to maximize their surface area
- unicellular organisms have mechanisms that are able to remove excess water by forming pools in the cytoplasm called contractile vacuoles
- multicellular are bathed in isotonic fluid therefore can function effectively because there is no net movement of water into or out of the cell
osmosis
- from a dilute solute to a high concentration solution
- the movement of water molecules from a of low concentration to high solute concentration
- water moves into sugary things