Carbohydrates (Chapter 15) Flashcards
Classify Monosacharides
trioses, tetraoses etc etc.
Aldoses or ketoses.
1) What is a polyol?
2) What are they used for?
3) Properties?
1) This is a monosaccharide where the aldehyde/ketone has been reduced to form an alcohol
2) They are used for weight reduction in food manufacturing and for diabetics.
3) Poorly absorbed. Yield half the energy of a normal monosaccharide.
How are disaccharides formed?
via condensation reactions.
What are oligosaccharides?
What is important to remember about them in regards to humans?
3-10 monosaccharides condensed together.
Oligosaccharides cannot be digested by humans.
1) What type of bond is cyclic glucose held by?
2) Which form is most thermodynamically favourable?
3) Which 3D shape is glucose?
1) Hemiacetal bond.
2) Cyclic form is most thermodynamically favourable.
3) Glucose is a chair shape…
Types of Isomerism in Carbohydrates?
- D and L isomerism
- Pyranose and Furanose
- Anomers
- Epimers
- Aldose and Ketose Isomers
Most natural form D or L?
D
Pyranose and Fyranose ring, and which is most common for glucose?
Pyran - 6 Carbon ring
Furan - 5 Carbon ring.
Pyran is most common for Glucose.
what bond joins ring of:
1) Aldose
2) ketose
1) Aldose are joint via Hemiacetal bond.
2) Ketose ring are join via Hemiketal bond.
What are the epimers of glucose?
Mannose, Galactose
Enantiomer of D Glucose?
L Glucose.
Disenantiomer of D Glucose
L galactose.
How can we test for glucose and why is it easy?
Aldoses are Reducing Agents.
Thus it is easy to test by using reduction of ALKALINE COPPER solution.
How can Glycosides form?
Glycosides formed when there is a condensation reaction between the:
-OH on the Anomeric carbon and a second compound.
What is an Algycone?
An Algycone is a glycoside where the second compound is not another sugar.
When are O-Glycosides formed?
What type of bond is it?
When the second group has an OH.
The bond is an acetal bond.
When are N-glycosides formed?
When the second group is a amine group.
What is common feature for all cardiac glycosides?
Give examples of Cardiac glycoside and what they do.
The Algycone group of a cardiac glycoside is always a STEROID.
eg: Oubain - somali poison.
Affects the Na+/K+ ATPase.
Streptomycin is another.
Which deoxy sugar do we find in glycoproteins
deoxy - L - Fructose.
Which deoxy sugar used an an inhibtor of glucose metabolism?
2 deoxyglucose.
What are glucoamines (Hexoamines) a component of?
1) Glycoproteins
2) Gangliosides
3) Glycosaminoglycans
What are invert sugars?
The hydrolysis of sucrose yields fructose which is strongly levarotary
1) What is starch?
2) What do we call the glyycosidic chain
2) which chains compose starch?
1) starch is a homopolymer of glucose.
2) We call the glycosidic chain: “Glucosan” or “Glucan”
3)It is composed of:
-AMYLOSE : non branched helical starch.
has 1-4 bonds
-AMYLOPECTIN: Branches starch.
has 24-30 glucose molecules consisting of 1-4 and 1-6(branch point) bonds.
What is the “Glycemic index”?
The glycemic index is a measure of:
-starchy foods digestibility
We see how much the blood glucose concentration rises compared to the reference.
How does glycogen differ to amylopectin?
what are the similarities?
Glycogen is more branched than amylopectin.
The similarities are that they both have the 1-4 and 1-6 bonds.
What is Inulin?
What can it be used for?
Polymer of fructose.
It’s very soluble in water so can be used to determine glomular filtration rate.
What are Dextrins?
These are “intermediates in the hydrolysis of starch”.
Type of bonds found in Cellulose?
Significance of these?
B1-4 bonds between B-D-glucose.
We have no enzymes to digest these.
However there is some bacterial metabolism of cellulose in the human colon.
What is Chitin?
Chitin is a polysaccharide in the exoskeleton of crustaceans.
It contains N-acetyl-D-Glycosamine joint via B1-4 bonds.
What is pectin?
Polymer of galacturonic acid joint by alpha1-4 bonds.
What are Glycosaminoglycans?
Carbohydrates containing:
- Amino Sugars
- Uronic acid
What are proteoglycans?
Glycosaminoglycans + protein molecule.
Examples of Proteoglycans?
- Hyaluronic Acid
- Chondroitin 4-sulfate
- Heparin
What is Hyaluronic acid made up of?
B- Glucuronic Acid
N-Acetylglucosamine
What is Chondroitin 4 Sulfate made up of?
B- Glucuronic Acid
N-Acetylgalactosamine sulfate
What is Heparin made up of?
Sulfated glucosamine
Sulfated iduronic acid.
