Module 08: Polysaccharides Flashcards
These are formed by the condensation of n molecules of monosaccharides with the removal of n-1 molecules of water
Polysaccharides
How are Polysaccharides formed?
condensation of n molecules of monosaccharides with the removal of n-1 molecules of water.
Why are Polysaccharides non-reducing?
Because condensation involves the carbonyl groups of the sugars, leaving only one free carbonyl group at the end of a big molecule
Structurally, Polysaccharides can be what?
unbranched (linear) or branched molecules.
What are the two (2) types of Polysaccharides?
(1) Homopolysaccharides
(2) Heteropolysaccharides
What are some examples of Homopolysaccharides?
(1) Starch
(2) Glycogen
(3) Cellulose
What are some examples of Heteropolysaccharides ?
(1) glycosaminoglycans,
(2) glycoproteins
These polysaccharides contain one sugar type
Homopolysaccharides
These polysaccharides contain more than
one sugar type
Heteropolysaccharides
Why do polysaccharides give off a negative result in Tollen’s and Benedict’s solutions?
they are not sweet and have limited water solubility
What are some functions of Homopolysaccharides?
(1) Storage
(2) Structural Elements
This Homopolysaccharides is used as a storage in plants.
Starch
This Homopolysaccharides is used as a storage in animals.
Glycogen
This Homopolysaccharides is used as a structural element in the plants cell wall.
Cellulose
This Homopolysaccharides is used as a structural element in the animal exoskeleton.
Chitin
What are some functions of Heteropolysaccharides:?
(1) Extracellular support
This Heteropolysaccharides functions as an extracellular support for the bacteria cell envelope
peptidoglycan
This is a storage polysaccharide is a polysaccharide that is a storage form for monosaccharides and is used as an energy source in cells (plants).
Starch
What is the monomeric unit of starch?
Glucose
This is a straight chain polymer with a (1 4) glycosidic bonds
Amylose
How much starch does amylose contain?
15 - 20% of the starch
What is the molecular mass of starch?
50,000 (up to 1000 glucose units)
This form of starch is a branched chain polymer.
Amylopectin
When can Amylopectin contain 80% to 85% of starch?
a (14) glycosidic bond for straight chain and a (16) for branch
What is the molecular mass of amylopectin?
300,000 (up to 100,000 glucose units) - higher than amylose
What can humans hydrolyze?
Human can hydrolyze alpha linkage but not beta linkage
This storage polysaccharides function as storage for humans and animals and contains only glucose units.
Glycogen
What is the structure of glycogen
Branched chain polymer – a (14) glycosidic bonds in straight chains and a (16) in branches (Three times more highly branched than amylopectin in starch)
What is the molecular mass of glycogen?
3,000,000 (up to 1,000,000 glucose units)
Excess glucose in blood stored in the form of _____________.
glycogen
What is the process of converting glucose to glycogen?
Glycogenesis
What is the process of converting glycogen to glucose?
Glycogenolysis
This is a linear Homopolysaccharides with b (1 4) glycosidic bond that serves as dietary fiber in food– readily absorbs water and results in softer stools
Cellulose
How many glucose units does cellulose contain?
5000 glucose units with molecular mass of 900,000
Why can’t animals and humans digest cellulose?
Humans don’t have enzymes that hydrolyze b (1 4) - so humans can not digest cellulose – animals also lack these enzymes but they can digest cellulose because they have bacteria in their guts to hydrolyze cellulose
How much cellulose is in cotton?
95%
How much cellulose is in wood?
50%
How much cellulose dietary fiber is desired everyday?
20 - 35 g
What is the structure of chitin?
Linear polymer with all b (14) glycosidic linkages - it has a N-acetyl amino derivative of glucose
What is the function of chitin?
Function is to give rigidity to the exoskeleton s of crabs, lobsters, shrimp, insects, and other arthropods
This is the most abundant natural polymer on earth and accounts for over half of the carbon in the biosphere
Cellulose
What comprises chitin?
(1) N-Acetylglucosamine
What are the 2 components of starch
2 components: Amylose (linear polymer) and Amylopectin (branched polymer)
This is the principal energy source of plants and is deposited in the chloroplasts in the form of insoluble granule
Starch
What does the helical conformation of amylose in starch do?
Helical conformation of amylose in starch is responsible for the blue-black colored complex with iodine solution
Why does amylose have a helical conformation?
Helical conformation because of the nature of the a (1 4) bond
Explain the structure of amylopectin?
Up to 106 molecules of glucose residues
mainly a(1 4),but has branched molecules via a(1 6) every 24-30 glucose residues.
In terms of the digestion of starch, this randomly hydrolyses the a(1 4) bonds but can not act on a(1–>6)
Saliva: amylase
In terms of the digestion of starch, this is a mixture of disaccharides (maltose) and trisaccharides (maltotriose), and oligosaccharides (dextrins) containing the a(1,6) branches (hydrolyzed by a-glucosidases and a debranching enzyme).
Small Intestine: pancreatic amylase
This is the storage polysaccharide of animals (skeletal muscle and liver). It structurally it resembles Amylopectin, but is more branched
Glycogen
How is glycogen degraded?
- glycogen phosphorylase (cleaves the (1 4) bonds)
- glycogen debranching enzyme (cleaves the (1 6) bonds).
These are polysaccharides with a repeating disaccharide unit containing an amino sugar and a sugar with a negative charge due to a sulfate or a carboxyl group.
Acidic polysaccharides
These are present in connective tissue associated with joints, cartilage, synovial fluids in animals and humans
Structural polysaccharide
What is the primary function of structural polysaccharide?
(1) Primary function is lubrication necessary for joint movement
(3) These are Heteropolysaccharides - have more than one type of monosaccharide monomers is present.
This is highly viscous and serve as lubricants in the fluid of joints and part vitreous humor of the eye.
Hyaluronic acid
How is Hyaluronic acid composed?
Alternating residues of N-acetyl-b-D-glucosamine and D-glucuronic acid.
This is an anticoagulant-prevents blood clots.
Heparin
How many disaccharide residues per chain comprises heparin?
15–90 disaccharide residues per chain.
This is a lipid molecule that has one or more carbohydrate (or carbohydrate derivative) units covalently bonded to it.
glycolipid
This is a protein molecule that has one or more carbohydrate (or carbohydrate derivative) units covalently bonded to it.
glycoprotein
Foods high in carbs content constitute over _____of the diet of most people of the world
50%
a balanced dietary food should contain about _____of carbohydrate:
60%
These are dietary monosaccharides or disaccharides - sweet to taste commonly referred to as sugars - 20 % of the energy in the US die
Simple carbohydrates
These are Dietary polysaccharides constituted of starch and cellulose and is normally not sweet to taste
Complex carbohydrates
How is glycemic effect classified?
how quickly carbs are digested
how high blood glucose rise
how quickly blood glucose levels return to normal
This has been developed for rating foods
Glycemic index (GI)
These are Polysaccharide that make up the bacterial cell walls.
Peptidoglycans
What is the structure of Peptidoglycans?
It is composed of amino sugars forming the glycan strand and cross-linked polypeptides and alternating amino sugars are NAG and NAM
What is the function of Peptidoglycans?
The peptidoglycan layer is responsible for reacting with crystal violet with gram (+) bacteria
This is a linear chain of alternating N-acetyl-glucosamine (NAG) and N-acetylmuramic acid (NAM).
Murein
What does each N-acetylmuramic acid (NAM).bear in peptidoglycans?
Each NAM bears a tetrapeptide composed of alternating L and D amino acids.
These are cross linked into sheets by bonds between the tetrapeptides.
Adjacent glycan chains
These are polymers of ribose or glycerol
Teichonic acids
the gram negative cell wall is composed of what?
Bilayer with usual phospholipids in the inner leaflet but with LPS on the outer leaflet, Lipid A, core polysaccharide, O antigen polysaccharide side chains.
These are toxic antigenic determinants in the the gram negative cell wall
Lipopolysaccharide (LPS)
A group of important membrane bound oligosaccharides found on the surface of RBCs
Blood Group Antigens or ABO Antigens
What happens when individuals are infused with blood with a different antigen?
The oligosaccharide chain elicit an Ab response causing agglutination of the blood
