Card Set Information
Carbohydrates: part 1
What two groups are considered as simple carbohydrates?
*2 monosaccharides joined by covalent bond
what are the 2 complex carbohydrates?
what are oligosaccharides?
short chains of monosaccharides (3-10)
what are polysaccharides?
long chains of monosaccharides (>10)
reactions between saccharides) HYdration reactions- Hydrolysis
an H2O molecule breaks a bond
reactions between saccharides) dehydration reactions:
reverse of hydrolysis, it removes H2O to bond 2 molecules together
what 2 consequences occur because we are mostly made up of water?
-hydrolysis happens easily
-dehydration reactions require energy to perform
what are the 3 major dietary monosaccharides?
what form of structure does the monosaccharide take in water?
a ring structure
how are monosaccharides often referred to depending on their functional group? (2)
can monosaccharides be broken down through mild hydrolytic reactions?
what are stereoisomers-enantiomers?
-same structure with similar chemical properties but in reverse form
Do stereoisomers-enantiomers react the same? If yes/no why?
no, they react completely different in the body due to stereo-specific receptors in the body
*D-glucose vs. L-glucose
*bodies can digest D-glucose but not L-glucose
Maltose α(1-4) bond
Lactose β(1-4) bond
sucrose α1 β2 bond
Oligosaccharides are made from a combination of which 3 monos?
which two foods are oligosaccharides found in?
-beans and peas
can our enzymes break down oligosaccharides bonds?
no they cannot
what type of enzymes can break down oligosaccharides? and what does this lead to?
microflora's enzymes, this leads to gas from bean and pea consumption
what is the major storage form of carbohydrates?
made of one type of monosaccharide
made of two or more types of monosaccharide
polysaccharides) which 3 polysaccharides are common in homopolysaccahrides?
are homopolysaccharides abundant in foods?
Are heteropolysaccharides abundant in foods?
no they are not
polysaccharides) what is the major storage form in plants?
polysaccharides) Starch- How are amylose formed?
glucose connected solely through alpha(1-4) glycosidic bonds
polysaccharides) Starch- How are amylopectin?
glucose connected through alpha(1-4) and alpha(1-6) glycosidic bonds
*it is a branched structure
polysaccharides) what is the major storage form for carbs in humans?
polysaccharides) Glycogen has similar bonds as...
polysaccharides) Cellulose is a major component of..
plant cell walls
polysaccharides) what is the main difference in structure that differ between starch and cellulose?
CEllulose has beta(1-4) instead of alpha(1-4) connecting the monosaccharides
polysaccharides) why is it significant that cellulose has beta bonds connecting monosaccharides instead of alpha?
our alpha-amylase can only digest alpha bonds thus makes cellulose indigestible by humans
*considered as indigestible fiber
digestion of polysaccharides) where does it begin?
in the mouth
digestion of polysaccharides) what are 2 things that salivary alpha-amylase do?
-breaks alpha(1-4) bonds to release glucose from starch and glycogen
-follows bolus into the stomach, then it is deactivated by pH level change
digestion of polysaccharides) which 2 types of bonds are resistant to salivary alpha-amylase?
-beta(1-4) bonds of cellulose
-alpha(1-6) bonds of amylopectin and glycogen
digestion of polysaccharides) what does pancreas do when bolus arrives at intestines? (2)
-release bicarbonate to increase pH
-releases pancreatic alpha-amylase to continue liberating glucose
digestion of polysaccharides) what are the limit dextrins?
1 alpha(1-6) + a few alpha(1-4)
*these were the ones that were left off because alpha-amylase could not break these down
digestion of polysaccharides) what happens to the "few" alpha(1-4) from limit dextrins ?
they are removed with a debranching enzyme
digestion of polysaccharides) after the few alpha(1-4) from limit dextrins are removed, whats left and what is it called?
Isomaltose, which is a 3-glucose triose with a 1 alpha(1-6) bond
digestion of polysaccharides) Finally what cleaves the alpha(1-6) bond to complete the breakdown to monosaccharides? and where can it be found?
alpha-dextrinase or isomaltase, which can be found at the brush border
carbohydrate inhibitor) what can beans with amylase inhibitors do?
-sugar and starch are absorbed as monosaccharides because it would inhibit their breakdown from poly to mono.
carbohydrate inhibitor) what can the concept of beans having amylase inhibitors theoretically present?
it could inhibit the digestion of carbohydrates and lead to weight loss
carbohydrate inhibitor) was the research on this sufficient?
no, it was spotty and insufficient
digestion of poly/di/mono) where does chemical digestion begin? and with what 2 things does it start with?
mouth, amylose and amylopectin
digestion of poly/di/mono) What happens to the activity of salivary amylase in the stomach?
it is inactivated bc of pH levels
digestion of poly/di/mono) is there carbohydrate digestion in the stomach?
digestion of poly/di/mono) what occurs in the small intestines?c
carbohydrate breakdown resumes bc the pancreas release pancreatic alpha-amylase
digestion of poly/di/mono) what occurs at the brush border?
final breakdown into monosaccharides occurs
digestion of poly/di/mono)what do maltase do?
breaks alpha(1-4) glycosidic bonds
digestion of poly/di/mono) what do lactase do?
breaks beta(1-4) glycosidic bonds
digestion of poly/di/mono) what does sucrase do?
breaks the alpha1beta2 glycosidic bond