Ch 2: Small Molecules and the Chemisrty of Life

Question 1

Main Atoms in Bio and their Bonds

Answer 1

H: 1
O: 2
S: 2
N: 3
C: 4
P:5

Question 2

3 ways to draw organic molecules

Answer 2

all atoms/all bonds
all atoms, all bonds, expcept to H
all carbons are missing-iplied by vertices

Question 3

R–>C=O,C-O

Answer 3

carboxylic acid; carboxyl group

Question 4

R-N+–>H3 (NH3)

Answer 4

amines; amino group

Question 5

R–>OH

Answer 5

alcohols; hydroxyl group

Question 6

R–>C=O, C-H

Answer 6

aldehydes, aldehyde group

Question 7

R–>C=O–>R

Answer 7

Ketones; keto group

Question 8

R–>SH

Answer 8

Thiols; sulfhydryl group

Question 9

R–>O-P=O-O-O

Answer 9

Organic Phosphates; Phosphate group

Question 10

covalent bond

Answer 10

the overlap orbitals btw atoms and the sharing of electrons

strong in terms of energy

bonds can either be non-polar or polar

Question 11

nonpolar covalent bonds

Answer 11

atoms of similar electronegativity

C-C, C-H, C-S

Question 12

Polar covalent bonds

Answer 12

atoms of dissimilar electronegativity

atoms with high eneg is partially neg and atom with the lower eneg is partially pos

H-O, H-N, C-O, C-N, P-O

Question 13

electronegativity

Answer 13

atoms that are more likely to attract electrons and are partially neg as a result

Oxygen has a high eneg

Hydrogen has a low eneg

C and S are equal

Question 14

Neg charged (eneg)

Answer 14

O, Cl, N

Question 15

neutral charges (eneg table)

Answer 15

S, C, P, H

Question 16

positive charged (eneg table)

Answer 16

Na, K

Question 17

non-polar bonds

Answer 17

C-C, H-C, C-S, H-S

Question 18

Polar bonds

Answer 18

H-O, H-N, C-O, C-N, P-O

Question 19

non-covalent bonds

Answer 19

do not involve the sharing of electrons

Question 20

Coulombic interactions

Answer 20

charge-charge interactions (plus/minus charges)

Question 21

ionic bonds

Answer 21

a type of coulombic interaction

attractions btw atoms that have a full pos charge and a full neg charge

ex: NaCl

Question 22

Cation

Answer 22

positive ions

move toward cathode (neg terminal)

Question 23

anions

Answer 23

neg ions

move toward anode (pos terminal)

Question 24

Hydrogen bonds

Answer 24

type of coulombic interaction

sharing of an H atom

Question 25

examples of H bonds

Answer 25

H bonds between water molecules

protein backbone

glutamite

lysine

Question 26

properties of water

Answer 26

strong hydrogen bonds
high specific heat
high heat vaporization
high cohesion

Question 27

Hydrophobic interactions

Answer 27

occurs between atoms that have nonpolar bonds

ex: C-H (mostly), C-C, C-S, S-H

in water, hydrophobic regions of molecules tend to cluster

Question 28

nonpolar molecules

Answer 28

do not form hydrogen bonds with water (hydrophobic)

weak interactions

Question 29

polar moleculess

Answer 29

form hydrogen bonds with water (hydrophilic)

strong charges/interactions

Question 30

Ex of hydrophobic interactions

Answer 30

two regions of water containing a globule of oil (nonpolar)

• Hydrophobic groups are surrounded by water molecules, but when two or more hydrophobic groups cluster (oil), a number of water molecules are squeezed out
• The “squeezed out” water molecules are then free to interact with the bulk solvent water
• NON-POLAR/HYDROPHOBIC SUBSTANCES TEND TO CLUSTER, BECAUSE IT MAXIMIZES THE NUMBER OF POSITIVE WATER INTERACTIONS, GIVING AN OVERALL LOWER ENERGY STRUCTURE

Question 31

Van der waals interactions

Answer 31

due to induced dipoles
are strongest when the interacting molecules are complementary in shape

(((((((((=stronger

()()()()= weaker