carbohydrates Flashcards
general formula for carbohydrates
cx(h20)y
types of carbohydrates
monosaccharide, disaccharide and trisacccharides
example of monosaccharides
glucose, fructose and galactose
example of disaccharides
maltose - glucose + glucose
sucrose - glucose + fructose
lactose - glucose + galactose
polysaccharides
starch, glycogen and starch
bio chemical test for presence of sugar
Benedicts test
reducing sugars
called so because they are involved in a reducing reaction. includes all monosaccharides and some disaccharides as well.
Test for reducing sugars
- add benedicts regaent to the solution and heat it in a water bath.
- if the color changes from clear blue to green, yellow, oranga and red brown due to the presence of insoluble copper oxide ppt, then it is positive.
Test for non reducing sugars
- non reducing sugar has to be broken down into monosaccharides first
- heated with hcl and then is made alkaline using an alkaline solution with sodium hydroxide.
- then is treated with benedicts reagent and heated in a water bath.
- if there is presence of red color then its positive for presence of non reducing sugars.
Test for starch
iodine test
iodine solution is orange brown in color. add a drop of iodine solution to the solid or liquid which is to be tested. if the color changes to blue black, then it indicates the presence of iodine.
why is starch suited for its role
- helix shape making it compact so it can fit a large amount of glucose in a small space.
branched structure increases the surface area for rapid hydrolysis back to glucose. - insoluble in water - doesnt affect the water potential.
- it is a large molecule so it can not cross across the membrane.
why is glycogen suited for its role
glycogen has 1-4 and 1-6 glycosidic bonds making it more branched which makes it more compact and suitable for storage.
- branching enables more free ends where glucose molecules can be added or removed.
monosaccharides
monosaccharides are the monomers from which larger carbohydrates are made.
what type of bond is formed when two monosaccharides are joined together?
glycosidic bond.
polysaccharides definition
polysaccharides are formed by the combination of many glucose units.
what is starch amde up of?
amylose and amylopectin.
amylose?
amylose is a component of starch. amylose has unbranced helix chain with 1,4 glycosidic bond between alpha glucose moleules. the helix shape makes the molecules compact for storage.
amylopectin?
amylopectin has 1,4 and 1,6 glycosidic bond between alpha glucose molecules providing a branced structure. the branches result in terminal glucose molecules which can be hydrolysed at the time of need during cellular respiration.
where is glycogen found?
in the form of granules in the liver and muscle cells as they have a very high cellular rate of respiration.
cellulose
polymer found in beta glucose.
b glucose is an inverse of alpha gluucose. so when it is inversed hydrogen bonds are formed.
what bonds are present in starch, glycogen and cellulose?
starch - 1,4 and 1,6 glycosidic bonds.
glycogen - 1,4 and 1,6 glycosidic bonds.
cellulose - 1,4 glycosidic bonds.
structure of cellulose
the polymers forms long straight chains.
the chains are held together in parallel chains by hydrogen bonds to form fibrils or micro fibrils.
why is it suited for its function?
the hydrogen bonds between parallel chains of micro fibrils gives a tensile strength to withstand the pressure.
-insoluble - doesnot affect water potential.
-cellulose fibres and other molecules combine to form a matrix which provides an additional strength.
