Carbs (mini-test 2) Flashcards
What is the most abundant macromolecule in food?
carbs
What atoms make up carbs
Cn(H2O)n
Where are good carbs found?
in nature
What are bad carbs?
processed and unnatural
ex: ice cream and cookies
Which molecules have clean energy?
fats and carbs
What are the functions of carbs?
-energy storage (most organisms obtain energy from the oxidation of carbs)
-structural components (found on cell membranes and plant cell walls, ex: cellulose of plant cell walls or chitin of insect exoskeletons)
What molecules have energy/store energy?
-fats
-AAs
-carbs
Which molecule is not “clean energy”?
proteins/AAs (so body does not like to use AAs for energy unless its desperate)
Carbohydrate classification is based on the number of monomeric units. Carbs can be classified as:
monosaccharides
-this is one sugar (simple sugar)
-this is the simplest carb molecule with the CnH2nOn formula
-monosaccharides usually have 3-7 carbons
-ex: glucose, fructose, galactose, mannose, ribose, etc
disaccharides
-this is 2 sugars (simple sugar)
-ex: sucrose is a table sugar that is made up of glucose and fructose, or lactose is a milk sugar that is made up of glucose and galactose
oligosaccharides
-this is 3-11 sugars (complex sugars)
-this is a short-chain of sugar subgroups
-ex: raffinose or stachyose
polysaccharides
-12+ sugars (complex sugars)
-long chain branched sugar subgroups
-2 types: homo and hetero-polysacchardies
-ex: cellulose, glycogen, chitin, starch
What are the simple carbs?
any sugar that is mono or disaccharide
Which sugars taste sweet?
any sugar that is mono or disaccharide (simple carbs only)
What are the complex carbs?
oligosaccharides and polysaccharides (3+ sugars)
Which sugars are usually found in foods?
polysaccharides
Natural polysaccharides are almost always…..
homo-polysaccharides
What are the 2 types of polysaccharides?
-homo polysaccharides (all sugars are the same)
-hetero polysaccharides (different sugars)
What is the 1st part of monosaccharide nomenclatures?
Is the carb an aldose or ketose? This is based on the position of the carbonyl group
What is an aldose?
C=O at C1
What is a ketose?
C=O at anywhere besides C1 (so any of the middle carbons of sugars)
If a sugar is an aldose, then where does numbering start?
at the aldehyde carbon
If a sugar is a ketose, then where does numbering start?
at the terminal carbon (closest to the carbonyl carbon)
How do you calculate the number of chiral carbons for ketoses?
total number of carbons - 3
ex: pentoketose
5-3 = 2 chiral carbons
What is the 2nd part of monosaccharide nomenclature?
number of carbons
How many carbons is a triose?
3 carbons
How many carbons is a tetrose?
4 carbons
How many carbons is a pentose?
5 carbons
How many carbons is a hexose?
6 carbons
A 4 carbon ketose would be called….
ketotetrose
A 5 carbon aldose would be called….
aldopentose
What are the different aldohexoses we talked about in class?
-glucose
-galactose
-mannose
What is an example of a ketohexose?
fructose
What is an example of an aldopentose?
ribose
What is the 3rd part of monosaccharide nomenclature?
common names
What is an example of an aldotriose?
glyceraldehyde
What is an example of a ketotriose?
dihydroxyacetone
What is this?
glyceraldehyde
What is this?
dihydroxyacetone
What is this?
ribose
What are the other names for glucose?
*there are a ton of varieties with the nomenclature
-glucoaldose
-hexoglucose
-aldohexose
-aldopyranose
-pyranhexose
-glucopyranose
How do you calculate the number of chiral carbons for an aldose?
total number of carbons- 2
ex: pentoaldose
5-2= 3 chiral carbons
Sugars naturally like which form- D or L form?
D form
Sugars are either D or L form based on the configuration of the chiral carbon furthest away from the….
carbonyl carbon
What are isomers?
same formula, different structures
How do you calculate the number of stereoisomers?
first find/calculate the chiral carbons
then take the number of chiral carbons and put it as: 2^x
x= number of chiral carbons, its an exponent of 2
example 2^2 = 4 stereoisomers
What is this?
D- glyceraldehyde
What is this?
L-glyceraldehyde
What is an isomer with glyceraldehyde?
dihydroxyacetone
(BUT they are NOT stereoisomers
ALL monosaccharides besides ______________ have at least one chiral center
dihydroxyacetone
How many stereoisomers does this molecule have?
2^3= 8
Is this monosaccharide D form or L form?
D form
How many stereoisomers does fructose have?
6 carbons- 3= 3 chiral carbons
2^3 = 8 stereoisomers
How many stereoisomers does galactose have?
6 carbons- 2 = 4 chiral carbons
2^4 = 16 stereoisomers
What is this?
D- glucose
What is this?
D-fructose
What is this?
D-galactose
What is this?
D- mannose
What are the 2 big categories for isomers?
1) constitutional (structural) isomers
2) stereoisomers (spatial isomers)
What are constitutional isomers?
-bonds/connections are different
-ex: aldose vs ketose, or galactose vs fructose
What are stereoisomers?
-same bonds
-aldose with aldose, or ketose with ketose
-ex: glucose and mannose, mannose and galactose, glucose and galactose
-stereoisomers can be further divided into diastereomers and enantiomers
What are diastereomers?
-NOT mirror image
-ex: L glucose with D galactose, both have 6 carbons and are aldoses but theyre different forms and structures
-there are 2 subcategories of diastereomers: cis/trans isomers and epimers
What are epimers?
diastereomers that are similar BUT differ by only 1 chiral carbon
ex: D glucose and D mannose differ only in one chiral carbon, so they are epimers
What are enantiomers?
-mirror images
-ex: D glucose and L glucose
Glucose and galactose are _____ epimers
C4
Glucose and mannose are ____ epimers
C2
Galactose and mannose differ in 2 chiral carbons. So they are not epimers. What are they?
stereoisomers
What is the 4th part of monosaccharide nomenclature?
carbohydrate ring structures
Monosaccharides with 5 or more carbons (mostly pentoses and hexoses) are going to form cyclic ring structures in the ___________ environment
aqueous
Aldohexoses tend to form a _________ ring structure when C1 aldehyde reacts with C5 hydroxyl
pyranose
Ketohexoses tends to form a __________ ring structure when C2 reacts with C5 hydroxyl
furanose
__________ can form both pyranose and furanose ring structures
aldopentose
How does a fisher projection turn into a ring structure?
isomerization reaction
Aldohexoses tend to form pyranose rings. A new chiral carbon is formed when a monosaccharide forms the ring structure. The new chiral carbon is called _________ carbon (the previous carbonyl carbon). 2 new stereoisomers are possible- when the hydroxyl group points down, it means alpha and when the hydroxyl group points up, it means beta
anomeric
What is it called when the hydroxyl group is pointed down?
alpha
What is it called when the hydroxyl group is pointed up?
beta
This deck does not cover all the notes!!! I got about halfway through, sorry
If you want to finish it let me know and I’ll give you editing power
