carbohydrates Flashcards
where are carbohydrates produced
by photosynthesis
what are carbs oxidised to produce
CO2 and H2O and energy
what is a monosaccharide
the simplest carbohydrates, no hydrolysis occurs
3 to 6 carbon atoms
a carbonyl group
several hydroxide groups
what is disaccharide
two monosaccharide units
what is a polysaccharide
many monosaccharide units
what is an olagasaccharide
3 to 10 monosaccharide units
what is an aldose
monosaccharides with an aldehyde group, also have many hydroxyl group
(triose, tetrose, pentose, hexose)
what is a ketose
monosaccharides with a ketone group with many hydroxyl group
fischer projection
used to represent carbohydrates
most oxidised group goes at the top
chiral carbons at in the middle of the structure
whats the difference between a D-glyceraldehyde and an L- glyceraldehyde
L- hydroxyl group on the left of the chiral carbon
D- hydroxyl group on the right of the chiral carbon
what determines the L or D status of a glyceraldehyde
the hydroxyl group farthest away from the chiral carbon
what is an epimer
structures that differ at one chiral centre
galactosemia
when there is a lack of enzymes reuired for galactose metabolism, results in an accumulation of galactose intermediates which has toxic effects in the liver, brain, kidneys and eyes
are cyclic or linear monosaccarides more stable
cyclic
when are cyclic monosaccharides produced
when the hydroxyl group of C-5 reacts with the aldehyde group or ketone group
whats the differnce between an alpha-D-glucose and a beta-D-glucose
alpha-below the ring
beta- above the ring
what happens when alpha-D-glucose or beta-D-glucose is in solution
clyclic structures open and close
how to test for sugars (ex. glucose) in the blood
use fehlings solution to convert a glucose into a gluconate by reducing inorganic ions such as copper
what is a reducing sugar
a sugar that will reduce inorganic ions such as Cu++
(ex. aldoses and ketoses)
what is a glucose oxidase test
‘dip stick test’ quicker way to test for glucose in the urine
whats the lifetime of red blood cells
120 days
what is lactose made up from
disaccharide between glucose and galactose
found in milk and milk products
what is a lactose intolerance
lack of lactase enzyme in small intestine which means lactose can pass onto the colon, bacteria start to ferment lactose causing stomach cramps and bloating
what class of carbohydrate is glycogen
highly branched polysaccharide composed of multiple glucose units
what does an alpha bond look like in glycogen
below the ring
what is sucrose made up from
glucose and fructose
what is maltose made up from
2 units of glucose
what is starch
plant form of carbohydrate ingested by humans
what is amylose
unbranched starch comprised of glucose units
hydrolysed by alpha-amylase secreted by salivary glands in the pancreas
amylopectin
branched form of starch
hydrolysed by alpha-amylase secreted by salivary glands in the pancreas
ratio of amylose and amylopectin in starch
20% amylose
80% amylopectin
cellulose
storage in plants
contains a beta-1,4 linkage (above the ring)
mammals lack cellulases
