Ch3: Important Molecules

Question 1

Amino Acids: Nonpolar, Hydrophobic

Answer 1

glycine
alanine
valine
methionine
leucine
isoleucine
proline
phenylalanine
tryptophan

Question 2

Amino Acids: Polar, Neutral

Answer 2

serine
threonine
asparagine
glutamine
cysteine
tyrosine

Question 3

Amino Acids: Polar, Acidic

Answer 3

aspartic acid

glutamic acid

Question 4

Amino Acids: Polar, Basic

Answer 4

histidine
arginine
lysine

Question 5

why is the structure of proline unique

Answer 5

proline has a ring in the side group. this ring is responsible for causing kinks in secondary structures; therefore, it is never seen in alpha-helix of protein structures.

Question 6

Diasteriomers

Epimers

Answer 6

non-superimposable, non-mirror image
Ex: D-glucose and D-galactose (different configuration at stereocenter 4)
to be more accurate, D-glucose and D-galactose are epimers(diastereomers differing in configuration at only one steroecenter)

Question 7

Enantiomers

Answer 7

non-superimposable mirror images
molecules that are exactly the same except one will have an R absolute configuration at a stereo center and the other molecule will have an S configuration at the stereocenter

Question 8

difference between absolute configuration designation and optical activity designation

Answer 8

absolute configuration: R or S
optical activity: D or L (dextro/levoROTATORY)
configuration doesn’t predict optical activity

Question 9

number of possible steroisomers

Answer 9

2^n where n=# of sterocenters

*be mindful of meso

Question 10

anomer

Answer 10

subclass of diastereomer. Epimers are non-superimposable, non-mirror images that differ at only one stereocenter. Anomers are simply that ring form of an epimer.
Ex: Epimer-linear glucose
anomer-ring glucose

Question 11

pyranose

Answer 11

six member sugar ring, five carbons with one oxygen ether bond

Question 12

furanose

Answer 12

5 membered ring; four carbons, one oxygen ether

Question 13

anomeric carbon

Answer 13

the carbon on a ringed sugar molecule that was the victim of nucleophilic attack by the deprotonated oxygen

Question 14

difference between alpha and beta sugars

Answer 14

beta sugars have their anomeric hydroxyl group cis to the terminal carbon group.
alpha sugars have their anomeric hydroxyl group on the opposite side of the ring of the terminal carbon group. further, alpha is down in the chair position. fishes in the sea

Question 15

triacylglycerol structure

Answer 15

glycerol molecule esterified to three fatty acid groups

Question 16

lipase

Answer 16

enzyme that hydrolyzes fat

Question 17

cholesterol’s effects on phospholipid membrane fluidity

Answer 17

stabilizing; keeps membrane fluidity at an optimum level

Question 18

terpene

Answer 18

molecule built from isoprenes
isoprene general formula: (C5H8)
terpenes are mutliples of the isoprene molecular formula

Question 19

steroid structure

Answer 19

polycyclic amphipath derived from cholesterol. generally tetracyclic

Question 20

linkage holding multiple phosphates together in ATP

Answer 20

anhydride

Question 21

reasons for ATP high energy

Answer 21

three phosphate groups have a great deal of negative charge in close proximity.

orthophosphate has a better resonance

orthophosphate interacts with water better than linked phosphates