New Carbohydrates Terms Flashcards
What are disaccharides?
they are composed of two monosaccharides (aldoses or ketoses) connected using an acetal linkage
what is an acetal linkage called?
glycoside
what is the alpha and beta config for sugars
the orientation of the acetal and the 6th carbon
trans-alpha
cis-beta
when do acetals interconvert
in the presence of acid otherwise they do no
they do not mutarotate nor are they reducing
but if one part of the molec is a hemiacetal then the whole molec collectively will mutarotate and be a reducing sugar
what is lactose
a d-galactose joined beta(1,4) to D-glucose
lactase is also known as
beta galactosidase and it can cleave the beta galactose linkage
what is sucrose comprised of
D-glucose and D-fructose
there is a alpha and beta acetal linkage
these two products together are sweeter than sucrose and are less likely to crystallize unlike sucrose
what is an invert sugar and where did the name come from
causes a chewy texture
its called that bc the first sugar rotates in one direction and the hydrolysis products rotate the opposite direction
polysaccharides
are not easily synthesized in the lab
starch
is used for energy storage in plant and can be divided into two type
amylose and amylopectin comprised of on D-glucose
amylose
unbranched d-glucs joined in an alpha 1,4 glycoside linkages and forms a helical structure where other things can fit inside
amylopectin
branched polymer of D-glucose in addition to the alpha 1,4 linkages the branching is alpha 1,6 every 24-30 units
glycogen
animal storage
humans have about 350g
similar to amylopectin but more branched
cellulose
is used for structural function
linear polymer of D-gluc linked beta 1,4
extra hydrogen bonding can occur bc its a straight chain
why can cows degrade cellulose
bc they have a simbiotic relationship with a bacteria that can digesst the cellulose into glucose where the cow then uses the glucose
