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Flashcards in Using Molecules to Build a Barrier Deck (36):
1

functional groups

(1) amino - NH2
(2) carboxyl - CO2H
(3) carbonyl - CO or COH
(4) hydroxyl - OH
(5) phosphate - PO4
(6) sulfhydryl - SH

2

cell membrane

surrounds cell
- regulates molecules/ions travelling btwn inner cell & environment
- protects cell
- thin, flexible

(aka plasma membrane)

"life's defining barrier "

3

atom

smallest particle that retains its ID during chem change
- building blocks of matter

4

molecule

result of 2+ atoms bonded juntos by IM forces
- chem formula

5

covalent bond

sharing e-
- nonmetal & nonmetal
- same
- polar or nonpolar covalent bonds
- essential for making life stable

SAME

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ionic bond

e- completely transfer from 1 atom to another
- donate & accept
- metal & nonmetal
- 1 (-) atom, 1 (+) atom

DIFF

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hydrocarbon

molecule containing only C & H
- nonpolar
- hydrophobic
- related to permeability

8

types of lipids

(1) steroid
(2) phospholipid
(3) fat (triacylglycerols or triglycerols)
(4) oils
(5) waxes

9

steroid

type of lipid
component of plasma membrane in orgs
- amphipathic

4 bulky rings + (distinguished) R group

(ie) cholesterol

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phospholipid

type of lipid
- (Bacteria & Eukarya) composed of fatty acids
- (Archaea) found w/ iosprenoid chains
- amphipathic

glycerol + charged R group + 2 fatty acids

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fat (triacylglycerols or triglycerols)

type of lipid
- nonpolar
- responsible for energy storage
- may be saturated or unsaturated

glycerol + 3 fatty acids

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lipid

organic substance
- no dissolve in H2O
- dissolves in polar organic solvents

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amphipathic

compounds that contain hydrophilic & hydrophobic elements
- responsible for plasma membrane

14

membrane permeability

tendency to allow a given substance to pass through

15

properties of substance that can cross lipid bilayer

(1) small & nonpolar molecules
(2) very small & uncharged, yet polar, molecules

(ie) O2 & H2O

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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

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hydrophilic

"water loving"
substances that interact w/ H2O

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hydrophobic

"water fearing"
substances that ≠ interact w/ H2O
interact w/ each other instead

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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)

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cell

highly organized compartment
- contains plasma membrane & conc. chemicals (aq)
- basic unit of matter
- anything smaller than cell ≠ living

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atomic #

# protons

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mass #

# protons + # neutrons

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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

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polar covalent bond

e- ≠ shared equally

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nonpolar covalent bond

e- shared equally

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organic

compound containing C-H
- C bonds w/ H N O S Mg S F or Cl
- made by living orgs

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lipid properties

(1) largely nonpolar
(2) hydrophobic
(3) not all polymers
(4) fluidity depends on "packing" of lipid molecules

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lipid fcns

(1) energy storage
(2) insulation
(3) cell membrane
(4) hormones - testosterone, estrogen, steroids, etc.

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saturated

lipids w/ all single bonds
- high melting points

C-C

straight

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unsaturated

lipids w/ @ least 1 double bond + single bonds

C=C

bent/kinked

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micelle

tiny droplets
- form circle
- hydrophilic heads turned outward
- hydrophobic tails turned inward

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variables of permeability

(1) saturation
(2) hydrocarbon chain length
(3) temp
(4) cholesterol

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saturation (permeability)

↑ saturation, ↑ permeability

- saturated = less space, stronger van der Waals interactions
- unsaturated allows more material to pass

34

hydrocarbon chain length (permeability)

↑ chain length, ↓ permeability

- denser membrane
- (small tail) interior < tightly held juntos

35

cholesterol (permeability)

↑ cholesterol, ↓ permeability

- bulky steroid rings
- cholesterol fill gaps in hydrophobic section of membrane

36

temperature (permeability)

↑ T, ↑ permeability

- room T = fluid physical state of phospholipids
- ↓ T, hydrophobic tails pack mas juntos
- very low T, lipid bilayers solidify