Lec 2 - carb digestion Flashcards
(23 cards)
What is a carbohydrate
food that are sources of digestible carbohydrates
In chemical terms, carbohydrates are?
polyhydroxy, aldehydes, ketones, and their derivatives
what does human milk contain?
7%carbohydrate
predominantly lactose
True or False: carbs are sources of rapidly digestible energy (avg: 4kcal/g)
True
what are available carbohydrates?
humans produce enzymes capable of cleaving their bonds so that they can be absorbed
what are unavailable carbohydrates?
the type of glycosidic bond, food microparticle structure and dose of carbohydrate influences digestibility
what do carbohydrates vary in
of carbons, aldose vs ketose, stereochemistry, & degree of polymerization
Characteristics of sucrose
- alpha 1-2 glycosidic bond
- C1 of glucose & C2 fructose
- alpha bond forms between C with same stereochem
characteristics of lactose
beta 1-4 glycosidic bond
C1 of glucose & C2 of galactose
characteristics of glycogen
alpha 1-4 glycosidic bonds in linear chain
alpha 1-6 glycosidic bonds in branching carbons
storage form of glucose found in the mammalian body
what makes up sucrose
glucose + fructose
what makes lactose
galactose & glucose
name the polysaccharide
glycogen
name the 3 monosaccarides
glucose fructose galactose
name the 2 disaccharides
sucrose and lactose
how do amylose and cellulose differ
glucose can exist as an anomer
what is a starch
polysaccharide of glucose linked by glycosidic bonds
where are starches stored in
seeds roots fruits
what is starch composed of
20% amylose & 80% amylopectin
True or false: amylose is alpha 1,6-linked with no branching
False, it is alpha 1,4-linked with alpha 1,6 branch points
amylose has a _____ structure
linear
what does the tight packing of amylose result in resistance to digestion
reduced surface area
