Carbohydrates Flashcards
What is the role of carbs in plants?
E transformation; tissue synth.
E reserves.
Structureal support for living plant
–> Fiber. Cellulose and hemicellulose.
Carbs are how much of animal diets (%)?
Up to 70% in animal diets.
Primary source of animal E
What are the carb tpyes in plant tissue?
Starch, cellulose.
WHat are the carbs in animal tissue?
Glycogen and glucose.
(<1%) in animal tissues.
Glycogen is most important stoage carb. Where is it kept?
Glycogen is kept in liver and skeletal. Glycogen in liver to be used anywhere in the body. Glycogen in the muscle can only be used in the muscle. No transport mech for it to leave the muscle.
What are the two major classes of carbohydrate and their two classes?
Which group of carbs occur in nature and are the end products/intermediates of digestion?
Monosaccarides
(glucose, fructose and galactose).
Sterioisomers
–> Which isomer can be metabolized in the animal body? D or L
Only D form can be metabolized in the body.
(animals want to get that D)
What is the most important hexose?
Glucose (6C).
What are other hexoses? (3)
Glucose, Galactose, Fructose.
Which hexose?
It is major end-prod of CH2O digestion in monogastrics some in ruminants. Commercially produced by hydrolysis of corn starch.
Glucose
Which hexose?
Combines with glucose to form lactose.
Componen of galactolipids found in plants…
Galactose
Which hexose?
Sweetest of all sugars.
Component of sucrose
Fructose
What are the important pentose sugars?
Ribose and deoxyribose.
Why are the pentose sugars important?
Backbone of DNA.
Ribose + adenine = adenosine.
–> ADP (constitent of E), AMP, cAMP.
Structural component of NAD and NADH ( accept or donate e- in REDOX runs).
What are some functions of Ribose?
Ribitol is a component of ribolfavin (B2 vitamin).
Series of runs.
Conversion of tryptophan into niacin (B3 vit).
What simple carb are Sucrose, lactose and maltose an example of?
hint:
2 monosaccharides attached by glycosidic bonds.
Disaccarides
What are the constituents of lactose?
Glucose and galactose
What are the consitients of sucrose?
Glucose and Fructose
What are the consitients of maltose?
Glucose and glucose!
Which is the anomeric carbon?
The one with the ketone group attached (CH=O)
How can you tell if it is an alpha or beta molecule?
Orientation on the ring. Alpha, the OH is on bottom of the ring.
Beta the OH on same side of the ring.
For disaccarides, if the anomeric carbon is alpha the linkage will also be alpha
Which disaccharide?
Only found naturally in milk. Glucose + Galactose in B(1-4) glycosidic bond.
Broken down by lactase; lactase expression
Lactose
Which disaccharide?
Most widely distributed disaccharide. Glucose + Fructose molecules.
Sucrose
Which disaccharide?
Two molecules of A (1-4)-linked glucose.
Partial hydrolysis of starch yields _____. Contained in malt beverages (beer).
Maltose
Which type of complex carb?
Monay monosaccharide units joined by glycosidic bond to form high molecular weight polymers.
ex) Stach, cellulose and glycogen
Polysacchardies
Which polysaccharide?
Reserve E in plants.
Two types of granules.
Alpha 1-4 linkage
Starch
Granules (amylose and amylopectin).
Cereal grians up to 70% starch.
Tubers, roots up to 30%
Which linkage type is starch?
Alpha 1-4 linkage
Which starch granule type?
Long unbranched chains of glucose connected by A(1-4) linkages.
UNBRANCHED!
SOluable in water
AMYLOSE
unbranched a(1-4).
Slowly digested b/c it is more compact.
Which starch granule type?
Branched-chain polymer with a(1-4) and a(1-6) linkages.
De-branching enzyme a(1-6), glucosidase for digestion
AMYLOPECTIN
Branched, so bigger and more SA so more rapidly digested.
Side chain branched are the a(1-6) linkages.
WHich polysaccharide?
Storage from of glucose in animals. Readily available E source.
Very similar to amylopectin, more highly branched.
A(1-4) and A(1-6) linkages
Glycogen
Found in liver and skeletal muscles. Mobilizes during fasting.
What type of insoluable fiber?
Mono-polysaccharide made up of only glucose.
Long linear repeating glucose units. B(1-4) linkages.
Insoluable in water
Indigestion by mammalian enzymes
Cellulose
Cellulose and hemicellulose are carbs.
Difference between cellulose and starch is the linkage.
What type of insolubale fiber?
Heteropolysaccharide substances. Sugars in backbone, side chains.
ex) Xylose, mannose, galactose.
B-(1-4) linkages. Indigestible by mammalian enzymes.
Hemicellulose
What type of insoluable fiber?
The plant content increases a plant matures.
Indigestable by mammalian enzymes; resistant to microbal enzymes.
Highly-branched poly-phenolic polymer composed of phenol units with strong bonding.
Lignin
What the the tree components of NDF?
Which type of soluable fibre?
Has an A(1-44) linked galatacturonic acid units?
Sugar (xylose, galactose etc.) side chains.
Microbal ferm
Pectin
What type of soluable fiber?
Homo-polymer of glucopyranose. Units with B(1-4), B(1-3) linkages.
Becomes very viscous in solution, which interferes with enzyme digestion.
Water soluble, very fermentable.
Commercially use as functional fibre.
B-Glucans
B-Glucans are added to poultry diets containing barely or oats.
B-glucanse breaks down B-Glucans
What type of soluable fiber?
B-linked xykise back, arabinose side chains. Causes poor digestibility in poultry.
Rye, wheat major sources.
It is added to poultry diets
Soluable Xylans
Xylanase breaks down Xulan into Xylose
What is the role fo soluable vs insolualbe fiber?
Soluable: Viscous env. (for humans) slows down digestion and gastric emptying. Decreasing intake.
Insoluable: Speed up gastric emptying. But increase stool bulk.
Dietary vs function fiber?
Dietary: Natural ingredients in the diet. Fiber is carrots, constituent of the plant.
Functional: Cellulose, pectin, isolated or extracted from plant and added to diet and supplement. Comercially produced.
What are some physiological effects of fiber?
Solubility in water.
Water-holding capacity and viscosity (in small intestine).
Absorption or binding ability
Degradability/fermentability. (in handout for microbes to produce VFAs).
Fiber has major roles in disease prevention and management.
What is the nutritional significance of stereoisomers?
a) Some isomers have not anomeric carbon
b) Some isomers cannot cyclize
c) Certain metabolic enzymes require a particular structure for metabolism
d) Certain isomers cannot polarize light
What is the nutritional significance of stereoisomers?
c) Certain metabolic enzymes require a particular structure for metabolism
A heteropolysaccharide that can be found in a forage diet fed to ruminants is ______ and it contains ______ linkages
A heteropolysaccharide that can be found in a forage diet fed to ruminants is Hemicellulose and it contains B(1-4) linkages
A homopolysaccharide that is important as a storage compound in plants is glycogen and glucose is its building block
Starch
or
Glucose
When ruminants are fed a diet containing a buffer (ex. Sodium Bicarb), the relative proportion of acetate in the rumen _______ primarily because feeding a buffer promotes a more neutral rumen pH, which favours the growth of cellulolytic bacteria.
Increases.
Feeding a buffer promotes a more neutral rumen pH, which favours the growth of cellulolytic bacteria
When ruminants are fed diets with a large particle size, the relative proportion of propionate in the rumen __________ primarily because feeding a diet with a large particle size reduces the risk of rumen acidosis which favours the growth of cellulolytic bacteria.
Decreases.
Feeding a diet with a large particle size reduces the risk of rumen acidosis which favours the growth of cellulolytic bacteria
After carbohydrate digestion has been initiated in the mouth of a pig consuming a typical carbohydrate-rich diet, which of the following types of carbs or intermediates of carb digestion flowing into the stomach?
a) Starch, cellulose and maltose
b) Acetate, prop, glucose
c) Galactose, Glucose, lignin
d) Cellulose, dextrins, starch
e) Starch, fructose, galactose.
d) Cellulose, dextrins, starch
Can’t be a) b/c it wouldn’t have been broken down maltose yet?
T/F
Glucose is transported form the intesinal lumen into the enterocyte by active transport using the Na-dependant glucose transporter 1 (SGLT-1) Protein, which requires the co-transport of NA into the cell.
T
T/F
All glucose transporters that are expressed in skeletal muscle in animals are insulin-dependaent, except GLUT-4.
F.
Only GLUT-4 is insulin dep.
T/F
Maltase is a brush-border enzymes that is required to complete the intestinal digestion of amylopectin in the small intestine in both monogastrics and ruminants
F
Match:
Sucrose-
Amylose-
Amylopectin-
a(1-4) linkage
a(1-6) linkage
Fructose, glucose
Sucrose- Fructose, glucose
Amylose- a(1-4) linkage
Amylopectin- a(1-6) linkage
Match:
Lactose-
Lignin-
Butyrate-
Ketone bodies
Indigestable
B(1-4) linkage
Lactose- B(1-4) linkage
Lignin- Indigestable
Butyrate- Ketone bodies
–> in the rumen epithelial to produce ketone bodies (B-hydroxybutyrate, acetoacetate)
Match:
Acetate
Glucose absorption
a-dextrinase
Liver energy storage
Digests limit dextrins
Glycogen
-Major circulating E substrate in ruminants-
Small intestine
Acetate -Major circulating E substrate in ruminants-
Glucose absorption- Small intestine
a-dextrinase- Digests limit dextrins
Liver energy storage- Glycogen
T/F
As a proportion of total starch, corn starch contains 25-30% amylose whereas pea starch contains 60 to 88% amylose. Therefore, pea starch is more slowly digested when compare to corn starch.
F
Amylose is more slowly digested.