Using Molecules to Build a Barrier Flashcards
RG 1
functional groups
(1) amino - NH2
(2) carboxyl - CO2H
(3) carbonyl - CO or COH
(4) hydroxyl - OH
(5) phosphate - PO4
(6) sulfhydryl - SH
cell membrane
surrounds cell
- regulates molecules/ions travelling btwn inner cell & environment
- protects cell
- thin, flexible
(aka plasma membrane)
“life’s defining barrier “
atom
smallest particle that retains its ID during chem change
- building blocks of matter
molecule
result of 2+ atoms bonded juntos by IM forces
- chem formula
covalent bond
sharing e-
- nonmetal & nonmetal
- same
- polar or nonpolar covalent bonds
- essential for making life stable
SAME
ionic bond
e- completely transfer from 1 atom to another
- donate & accept
- metal & nonmetal
- 1 (-) atom, 1 (+) atom
DIFF
hydrocarbon
molecule containing only C & H
- nonpolar
- hydrophobic
- related to permeability
types of lipids
(1) steroid
(2) phospholipid
(3) fat (triacylglycerols or triglycerols)
(4) oils
(5) waxes
steroid
type of lipid
component of plasma membrane in orgs
- amphipathic
4 bulky rings + (distinguished) R group
(ie) cholesterol
phospholipid
type of lipid
- (Bacteria & Eukarya) composed of fatty acids
- (Archaea) found w/ iosprenoid chains
- amphipathic
glycerol + charged R group + 2 fatty acids
fat (triacylglycerols or triglycerols)
type of lipid
- nonpolar
- responsible for energy storage
- may be saturated or unsaturated
glycerol + 3 fatty acids
lipid
organic substance
- no dissolve in H2O
- dissolves in polar organic solvents
amphipathic
compounds that contain hydrophilic & hydrophobic elements
- responsible for plasma membrane
membrane permeability
tendency to allow a given substance to pass through
properties of substance that can cross lipid bilayer
(1) small & nonpolar molecules
(2) very small & uncharged, yet polar, molecules
(ie) O2 & H2O
properties of substance that cannot cross a lipid bilayer
(1) large & uncharged substance
(2) ions, unless helped - charged compounds & large polar molecules dissolve in H2O
hydrophilic
“water loving”
substances that interact w/ H2O
hydrophobic
“water fearing”
substances that ≠ interact w/ H2O
interact w/ each other instead
lipid bilayer
basic strucutural element of all cellular membranes
- two sheets of phospholipid layers align
- hydrophobic tails oriented toward inside
- hydrophilic heads oriented toward outside
- selectively permeable (small, nonpolar molecules)
cell
highly organized compartment
- contains plasma membrane & conc. chemicals (aq)
- basic unit of matter
- anything smaller than cell ≠ living
atomic #
protons
mass #
protons + # neutrons
most common elements in orgs
(1) hydrogen - H
(2) carbon - C
(3) nitrogen - N
(4) oxygen - O
(5) sodium - Na
(6) magnesium - Mg
(7) phosphorus - P
(8) sulfur - S
(9) chlorine - Cl
H C N O Na Mg P S Cl
polar covalent bond
e- ≠ shared equally
nonpolar covalent bond
e- shared equally
organic
compound containing C-H
- C bonds w/ H N O S Mg S F or Cl
- made by living orgs
lipid properties
(1) largely nonpolar
(2) hydrophobic
(3) not all polymers
(4) fluidity depends on “packing” of lipid molecules
lipid fcns
(1) energy storage
(2) insulation
(3) cell membrane
(4) hormones - testosterone, estrogen, steroids, etc.
saturated
lipids w/ all single bonds
- high melting points
C-C
straight
unsaturated
lipids w/ @ least 1 double bond + single bonds
C=C
bent/kinked
micelle
tiny droplets
- form circle
- hydrophilic heads turned outward
- hydrophobic tails turned inward
variables of permeability
(1) saturation
(2) hydrocarbon chain length
(3) temp
(4) cholesterol
saturation (permeability)
↑ saturation, ↑ permeability
- saturated = less space, stronger van der Waals interactions
- unsaturated allows more material to pass
hydrocarbon chain length (permeability)
↑ chain length, ↓ permeability
- denser membrane
- (small tail) interior < tightly held juntos
cholesterol (permeability)
↑ cholesterol, ↓ permeability
- bulky steroid rings
- cholesterol fill gaps in hydrophobic section of membrane
temperature (permeability)
↑ T, ↑ permeability
- room T = fluid physical state of phospholipids
- ↓ T, hydrophobic tails pack mas juntos
- very low T, lipid bilayers solidify
