Carbohydrates Flashcards
What is the principal role of carbs?
to provide energy
What are carbs made of?
carbon, hydrogen and oxygen groups
True or False:the nature of covalent bonds linking monoscchriades into polysaccharides is much more varied than that of peptide bonds
True
What is maltose
glucose glucose
What is sucrose
glucose and fructose
What is lactose
glucose and galactose
What is the proper formula for a carb besides CHO?
CH2O
How are aldehydes or ketones referred to when in a sugar?
Aldose or ketose
How is fructose use in the cell?
converted to usable glucose derivatives
How are monosacchirdes referred to when speaking about the amount of carbons?
3; Triose
4: Tetros
5: pentose
6: hexose
7: heptose
What is glyceraldehyde?
3c-carbon aldotriose molecule
Dihydroxyacetone
this is a ketotriose. the ketone is in the middle and there are three carbons
enantiomer
non-superimposable mirror images
How is the D or L CONFIGURATION determined?
it depends on what side the final OH group is on- look farthest away from carbonyl
What if the rotation value is 0?
the molecule is optically inactive and there is a racemic mixture occring and it is designated as +/-
True or false: Fischer projections show sticks coming out of the central molecule
False: The projections show if the bond is coming forward or backward.
What is the difference between d-glucose and d-galactose?
The placement of the -OH is different in the molecule. They are c-4 epimers
What is a epimer?
pair of carbohydrates that differ in configuration at only one asymmetric center
What is a hemiacetal?
a molecule that has a central carbon with one -OH group, one -OR group, one R group and a H.
What is a hemiketal?
a molecule with two r groups, one -OH group and one -OR group
True or False: glucose and fructose are in open chain structures
False: they are usually in cyclic structures
Which carbons react with each other to create intramolecular hemiacetal?
C-1 aldehyde and the C-5- OH group
What is the 6-member ring called ?
pyranose
Which is the anomeric carbon?
It is carbon 1 or the carbon next to the O that has a oh and H group on it.
What is the cyclic form name of alpha d glucose?
d-glucopyranose
What carbons react in a hemiketal to form a ring?
C-2 keto group reacts with the C-5 OH group
What is the hemiketal referred to as?
fructofuranose
What are Haworth Projections?
provides a 2-d structure of the ring
What are the two classifications of cyclic ring structures?
Chair and boat
What produces a color change when testing sugars?
the reducing of the carbohydrate
Fehling’s solution
monosaccharides in solution change from blue to red (both aldehyde and ketone essentially)
Benedict’s Reagent
blue-copper containing solution gives a very distinct brick red (copper II oxide)
Tollen’s Reagent
creation of a ‘silver mirror’ on the inside of a test tube
Which reagents produce a redox reaction because they are oxidizing reagents?
Fehlings, Benedicts, and Tollen’s
What is formed when the aldehyde form of a carbohydrate joins with a amino group in a protein?
creation of an advanced glycation end product
Are all mono and disaccharides (With the exception of glucose) reducing sugars?
Yes
What can an aldehyde group be reduced to?
an alditol
Why is NADH needed in the body?
it is needed as a coenzyme for aldose reductase to change glucose to sorbitol
Where and how is excess glucose stored?
In muscle and liver and in the form of glycogen
True or false: sorbital is NOT a epimer of glucose
False, it is an epimer of glucose
What are the other names for fructose?
levulose or fruit sugar
What reaction can fructose undergo?
The Maillard reaction
What happens when fructose is malabsorbed?
the fructose builds up in the liver and can cause IBS
What is inulin?
the form in which some plants store fructose
How is galactose metabolized to glucose?
through the Leloir pathway
Glucose is converted to galactose in the body how?
by hexogenesis
What is galactosaemia
defects in galatose metabolism
What linkage does Maltose have?
alpha 1-4 glycosidic linkage
Glucose- glucose
What linkages does lactose have?
beta 1-4 glycosidic linkage
glucose and galactose
What linkages does sucrose have?
alpha 1,2 glycosidic bonds between alpha d glucose and beta- d fructose. ( not on anomeric carbons)
Is sucrose a reducing sugar?
no
What are homopolysaccharides?
Sugars composed of a single type of sugar
What are Heteropolysaccharides?
sugars made of more than two types of sugar units.
What are the 5 features that define polysaccharides?
- Monomeric units making it up
- Sequence of sugar units
- Types of glycosidic binds linking monomeric units
- Approximate # of sugar units
- Degree of structural branching
What are the two storage forms of polysaccharide?
amylose and amylopectin
What is amylose?
a linear, unbranched chain of alpha-d glucose with 1,4 bonds. It contains a reducing and non-reducing end
What kind of backbone does Amylopectin have?
a glucose backbone
Is glycogen a highly branched molecule?
yes, it alpha 1,6 linkages
What does glycogen have in common with amylopectin?
it has a single reducing end and numerous non-reducing ends
How is glycogen hydrolysed?
by alpha amylase
What is cellulose made up of
beta d- glucose
What specific molecule is in Chitin?
N-acetylglucosamine linked by beta 1-4 linkage
