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What two groups are considered as simple carbohydrates?
-monosaccharides
- -disaccharides
- *2 monosaccharides joined by covalent bond
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what are the 2 complex carbohydrates?
-oligosaccharides
-polysaccharides
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what are oligosaccharides?
short chains of monosaccharides (3-10)
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what are polysaccharides?
long chains of monosaccharides (>10)
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reactions between saccharides) HYdration reactions- Hydrolysis
an H2O molecule breaks a bond
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reactions between saccharides) dehydration reactions:
reverse of hydrolysis, it removes H2O to bond 2 molecules together
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what 2 consequences occur because we are mostly made up of water?
-hydrolysis happens easily
-dehydration reactions require energy to perform
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what are the 3 major dietary monosaccharides?
-glucose
-fructose
-galactose
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what form of structure does the monosaccharide take in water?
a ring structure
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how are monosaccharides often referred to depending on their functional group? (2)
-aldoses
-ketoses
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can monosaccharides be broken down through mild hydrolytic reactions?
no
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what are stereoisomers-enantiomers?
-same structure with similar chemical properties but in reverse form
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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
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Glucose+Glucose=
Maltose α(1-4) bond
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Glucose+Galactose=
Lactose β(1-4) bond
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Glucose+Fructose=
sucrose α1 β2 bond
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Oligosaccharides are made from a combination of which 3 monos?
- -glucose
- -fructose
- -galactose
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which two foods are oligosaccharides found in?
-beans and peas
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can our enzymes break down oligosaccharides bonds?
no they cannot
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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
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what is the major storage form of carbohydrates?
polysaccharides
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polysaccharides) Homopolysaccharides:
made of one type of monosaccharide
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polysaccharides) Heteropolysaccharides:
made of two or more types of monosaccharide
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polysaccharides) which 3 polysaccharides are common in homopolysaccahrides?
- -starch
- -glycogen
- -cellulose
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are homopolysaccharides abundant in foods?
yes
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Are heteropolysaccharides abundant in foods?
no they are not
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polysaccharides) what is the major storage form in plants?
starch
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polysaccharides) Starch- How are amylose formed?
glucose connected solely through alpha(1-4) glycosidic bonds
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polysaccharides) Starch- How are amylopectin?
- glucose connected through alpha(1-4) and alpha(1-6) glycosidic bonds
- *it is a branched structure
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polysaccharides) what is the major storage form for carbs in humans?
glycogen
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polysaccharides) Glycogen has similar bonds as...
amylopectin
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polysaccharides) Cellulose is a major component of..
plant cell walls
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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
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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
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digestion of polysaccharides) where does it begin?
in the mouth
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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
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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
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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
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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
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digestion of polysaccharides) what happens to the "few" alpha(1-4) from limit dextrins ?
they are removed with a debranching enzyme
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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
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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
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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.
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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
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carbohydrate inhibitor) was the research on this sufficient?
no, it was spotty and insufficient
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digestion of poly/di/mono) where does chemical digestion begin? and with what 2 things does it start with?
mouth, amylose and amylopectin
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digestion of poly/di/mono) What happens to the activity of salivary amylase in the stomach?
it is inactivated bc of pH levels
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digestion of poly/di/mono) is there carbohydrate digestion in the stomach?
no
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digestion of poly/di/mono) what occurs in the small intestines?c
carbohydrate breakdown resumes bc the pancreas release pancreatic alpha-amylase
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digestion of poly/di/mono) what occurs at the brush border?
final breakdown into monosaccharides occurs
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digestion of poly/di/mono)what do maltase do?
breaks alpha(1-4) glycosidic bonds
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digestion of poly/di/mono) what do lactase do?
breaks beta(1-4) glycosidic bonds
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digestion of poly/di/mono) what does sucrase do?
breaks the alpha1beta2 glycosidic bond
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