Using Molecules to Build a Barrier

Question 1

functional groups

Answer 1

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

Question 2

cell membrane

Answer 2

surrounds cell

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

(aka plasma membrane)

“life’s defining barrier “

Question 3

atom

Answer 3

smallest particle that retains its ID during chem change

- building blocks of matter

Question 4

molecule

Answer 4

result of 2+ atoms bonded juntos by IM forces

- chem formula

Question 5

covalent bond

Answer 5

sharing e-

• nonmetal & nonmetal
• same
• polar or nonpolar covalent bonds
• essential for making life stable

SAME

Question 6

ionic bond

Answer 6

e- completely transfer from 1 atom to another

• donate & accept
• metal & nonmetal
• 1 (-) atom, 1 (+) atom

DIFF

Question 7

hydrocarbon

Answer 7

molecule containing only C & H

• nonpolar
• hydrophobic
• related to permeability

Question 8

types of lipids

Answer 8

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

Question 9

steroid

Answer 9

type of lipid
component of plasma membrane in orgs
- amphipathic

4 bulky rings + (distinguished) R group

(ie) cholesterol

Question 10

phospholipid

Answer 10

type of lipid

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

glycerol + charged R group + 2 fatty acids

Question 11

fat (triacylglycerols or triglycerols)

Answer 11

type of lipid

• nonpolar
• responsible for energy storage
• may be saturated or unsaturated

glycerol + 3 fatty acids

Question 12

lipid

Answer 12

organic substance

• no dissolve in H2O
• dissolves in polar organic solvents

Question 13

amphipathic

Answer 13

compounds that contain hydrophilic & hydrophobic elements

- responsible for plasma membrane

Question 14

membrane permeability

Answer 14

tendency to allow a given substance to pass through

Question 15

properties of substance that can cross lipid bilayer

Answer 15

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

(ie) O2 & H2O

Question 16

properties of substance that cannot cross a lipid bilayer

Answer 16

(1) large & uncharged substance

(2) ions, unless helped - charged compounds & large polar molecules dissolve in H2O

Question 17

hydrophilic

Answer 17

“water loving”

substances that interact w/ H2O

Question 18

hydrophobic

Answer 18

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

Question 19

lipid bilayer

Answer 19

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)

Question 20

cell

Answer 20

highly organized compartment

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

Question 21

atomic #

Answer 21

protons

Question 22

mass #

Answer 22

protons + # neutrons

Question 23

most common elements in orgs

Answer 23

(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

Question 24

polar covalent bond

Answer 24

e- ≠ shared equally

Question 25

nonpolar covalent bond

Answer 25

e- shared equally

Question 26

organic

Answer 26

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

Question 27

lipid properties

Answer 27

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

Question 28

lipid fcns

Answer 28

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

Question 29

saturated

Answer 29

lipids w/ all single bonds - high melting points C-C straight

Question 30

unsaturated

Answer 30

lipids w/ @ least 1 double bond + single bonds C=C bent/kinked

Question 31

micelle

Answer 31

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

Question 32

variables of permeability

Answer 32

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

Question 33

saturation (permeability)

Answer 33

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

Question 34

hydrocarbon chain length (permeability)

Answer 34

↑ chain length, ↓ permeability - denser membrane - (small tail) interior < tightly held juntos

Question 35

cholesterol (permeability)

Answer 35

↑ cholesterol, ↓ permeability - bulky steroid rings - cholesterol fill gaps in hydrophobic section of membrane

Question 36

temperature (permeability)

Answer 36

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