Biological Molecules Flashcards
What is the suffix that designates a carbohydrate?
-ose
What is the difference between oligosaccharide and polysaccharide?
oligosaccharide = neither simple nor complex carbs, usually containing 3-10 repeating monomers
polysaccharide = complex carbs, made of >10 monomers
What are the 2 classifications of open-chain or linear forms of monosaccharides?
aldoses and ketoses
What is the difference between a D (+) sugar and an L (-) sugar? (consider fisher projection structures)
D sugar: highest number chiral carbon -OH on right
L sugar: highest number chiral carbon -OH on left
The human body has enzymes that recognize ______ sugars.
a) D
b) L
a) D
TRUE or FALSE: D and L correspond to R and S.
FALSE –> no relation at all
Draw the D-glucose and L-glucose enantiomers. Pay attention to the bottom cross.
ye draw it bruh
List the following from highest to lowest priority group (when designating D or L):
carboxylic acid, alcohol, carbonyl
carboxylic acid > carbonyl > alcohol
hint: most oxidized is highest priority and least oxidized is lowest priority
What is the “bottom cross rule” in terms of designating D and L? When can this rule be applied?
bottom cross rule = the direction of OH on the bottom cross of the sugar (in a fisher projection) determines D or L (i.e. if OH on left, then L enantiomer)
*can only be applied if highest priority carbon is at the top of the fisher projection diagram
How do you determine if 2 sugar molecules are enantiomers?
OPPOSITE absolute configuration of ALL chiral carbons
How do you determine if 2 sugar molecules are diastereomers?
> /= 1 chiral carbons with OPPOSITE absolute configuration AND >/= 1 chiral carbons with SAME absolute configuration
How do you determine if 2 sugar molecules are epimers?
EXACTLY 1 chiral carbon with opposite absolute configuration AND >/= 1 chiral carbon with the SAME absolute configuration
What reagents need to be added to an aldehyde/ketone to form a hemiacetal/hemiketal?
alcohol (with desired functional (R) group) + acid
TRUE or FALSE: even if a carbonyl/hydroxy group is located on the same molecule as an aldehyde/ketone, an intramolecular nucleophile addiction cannot take place
FALSE –> intramolecular reaction can occur to yield cyclic hemiacetal/hemiketal
TRUE or FALSE: furanose (5 member ring) is more stable than pyranose (6 member ring)
FALSE –> pyranose (6 member ring) is more stable than furanose (5 member ring)
How do you identify the anomeric carbon in a cyclic structure?
anomeric carbon is the only carbon with 2 oxygen groups attached to it
What is the difference between the alpha and beta anomer of D-glucose (structurally)? Which one is the major anomer and which one is the minor anomer? Draw the structures.
alpha = minor = OH at C1 is TRANS to C2OH at C5
beta = major = OH at C1 is CIS to C2OH at C5
did you draw it lol (hint: change the configuration at C1 of glucose)
Why is the beta-anomer of D-glucose major in comparison to the alpha-anomer?
beta is more stable because all substituents are equatorial (less sterically hindered)
How is Haworth projection (for chair/planar conformation) related to Fisher projection?
OH groups pointing LEFT in Fisher go UP in Haworth
OH groups pointing RIGHT in Fisher go DOWN in Haworth
In the Haworth projection for sugars, which direction does the CH2OH on C5 point for D sugars? What about for L sugars?
D sugar: CH2OH on C5 points UP
L sugar: CH2OH on C5 points DOWN
Draw the D glucose fischer projection and the beta D glucose haworth projection.
now go check it
What reagents should be added to form an acetal/ketal from a hemiacetal/hemiketal?
alcohol (with new R group) and acid
hint: same as from acetaldehyde/ketone to hemiacetal/hemiketal
What reagents can be used to reduce a sugar?
Tollens’ reagent and Benedict’s reagent
What kind of linkage is yielded when forming disaccharides?
1,4-linkage (glycosidic)
What monomers make up lactose? What kind of bond links the monomers?
D-galactose + D-glucose
beta-1,4 glycosidic bond
What monomers make up maltose? What kind of bond links the monomers?
2 D-glucose molecules
alpha-1,4’ glycosidic bond
What monomers make up sucrose? What kind of bond links the monomers?
D-glucose + D-fructose
1,2’-glycosidic bond (between both anomeric carbons)
What monomers make up cellulose? What kind of bond links the monomers?
chain of glucose molecules
beta-1,4’ glycosidic bond
What monomers make up amylose? What kind of bond links the monomers?
chain of glucose molecules
alpha-1,4’ glycosidic bond
What monomers make up amylopectin? What kind of bond links the monomers?
BRANCHED chain of glucose
alpha-1,4’ glycosidic bonds + alpha-1,6’ glycosidic bonds (at branching points)
What monomers make up glycogen? What kind of bond links the monomers?
BRANCHED chain of glucose
alpha-1,4’ glycosidic bonds + alpha-1,6’ glycosidic bonds (at branching points)
(hint: same as amylopectin??? …unless I read the book wrong :(((( )
TRUE or FALSE: amino acids can also be designated with D or L configuration
TRUE –> look at NH2 direction instead of OH direction in Fischer projection
____ amino acids are found in animal proteins.
a) D
b) L
b) L
What is the name of the reaction for breaking down a triglyceride into its glycerol backbone and fatty acid tails? What reagent is needed for this reaction to occur?
lipolysis/saponification
H2O or -OH
What does the structure of triglyceride consist of? Draw it.
glycerol backbone and 3 fatty acid tails
yeah now draw it
What does the structure of phospholipids consist of? Draw it?
glycerol, 2 fatty acid tails, one phosphate group
did you draw it?
What does the structure of sterols consist of? Draw a steroid and then draw a sterol.
4 rings
see page 211 in chem cc for the diagrams
What is the difference between a steroid and a sterol?
steroid is very hydrophobic
sterol has an OH group (alcohol)
be able to recognize the terpene structures on page 212 of chem cc!
go look…do you recognize them?
What kind of bond forms between 2 nucleic acids?
phosphodiester link
what are the two things that carbohydrates need to be able to do in order to be a reducing sugar
- convert to the open chain form
2. have an aldehyde group
what are examples of non reducing sugars
acetals and glycosides
true or false - all aldoses are reducing sugars
true
