examples of eukaryotic cells
animals, plants, fungi
examples of prokaryotic cells + how much of our bodies do they make up?
bacteria
2-3% of body mass
most are not harmful/beneficial
cell
structure containing macromolecules and organelles, surrounded by phospholipid bilayer
cell membrane
thin with hydrophobic + hydrophilic parts. has macromolecules contained in it (carbs and proteins)
what is phospholipid bilayer made of
each molecule: polar group, phosphate group, glycerol, fatty acid chains
hydrocarbon chains
what the fatty acid tails are made up of, 16-18 carbons
saturated -> only single bonds
unsaturated -> double bonds (create bends)
steroids
4-hydrocarbon ring structure
hydrophobic and hydrophilic components
- lipid micelles (hydrophobic ends converge in the middle)
-> form automatically and move around by themselves
factors that affect fluidity
- temperature: hot = more fluid
- amount of cholesterol: need a balance (in really cold temps, want less)
- number of carbons (less carbons = more fluid)
- saturated vs unsaturated fatty acids
molecules moving through cell membrane
Yes: small, uncharged molecules, hydrophobic
No: large, charged, hydrophilic
*protein channels can facilitate transport
Passive diffusion
- down the gradient
- does not require ATP
- passes through membrane directly
transport-facilitated diffusion
- down the gradient but through a channel
- still does not require ATP
active transport
- up the concentration gradient
- does require ATP
- movement through protein pumps
EX: sodium-potassium pump (for every 3 sodium leaving, 2 potassium can come in)
what is osmosis
- movement of water down a concentration gradient
- uses aquaporins (transport-facilitated diffusion)
- hypertonic: higher concentration
- isotonic: no net movement of water since same concentration
- hypotonic: less concentrated
