Mononomers + carbohydrates Flashcards
Where is a glycosidic bond used
To join together glucose
How can starch be tested for ?
-add iodine dissolved in potassium iodide solution.
- if there is a starch present, the sample changes from browny-orange to a dark blue-black colour
When is a polysaccharide formed ?
Condensation of many glucose units
Describe a test for non-reducing sugar?
-Add dilute hydrochloric acid to the sample
-Heat in a water bath that has been brought to the boil
-Neutralise the solution with sodium hydrogencarbonate
-carry out benedicts test as normal
Example of non-reducing sugar?
Sucrose
4 reducing sugars
Galactose, fructose, glucose and maltose
How test for reducing sugar ?
-Add benedicts reagent to a sample and heat it in a water bath that has been brought to a boil
-Positive = form a coloured ppt from blue to red ( lowest conc. to highest )
How can you compare the results of a test for reducing sugars ?
-Compare the colour change (blue to red )
-Filter and weigh the precipitate
How can you compare the results of a test for reducing sugars ?
-Compare the colour change (blue to red )
-Filter and weigh the precipitate
How is the structure of glycogen related to its function? (4)
-Branched, so compact for storage
-Insoluble, so does not effect water potential of cells it is stored in
-Branched structure, so more ends for faster hydrolysis
-Contains glucose, so provides respiratory substrate
Briefly describe the diagrams of the polymers; cellulose, starch and glycogen.
Starch:
-amylopectin = branched
-amylose = unbranched coil/helix
-Cellulose would be in straght, unbranched rows
-glycogen - branched
How does the structure of starch help to fulfill its function?
-amylose is coiled/helix, so compact
-amylopectin is branched, so more ends for faster hydrolysis
-insoluble, does not effect water potential of cells it is stored in
-Contains glucose, so provides respiratory substrate
What is starch made up of (what two polysaccharides)?
2 different polysaccharides- amylose, amylopectin
Which monomers of glucose are; starch, glycogen, cellulose
starch-alpha
glycogen-alpha
cellulose-beta
remember as: walls are for betas, live outisde
How is starch formed
Condensation of a glucose
How is cellulose formed
condensation of b glucose
how is glycogen formed
condensation of a glucose
what are a and b glucose ?
isomers of glucose
How are dissacharides formed
Disaccharides are formed by the condensation of two monosaccharides
lactose is a __ formed by condensation of __
lactose is a disaccharide formed by condensation of a glucose molecule and a galactose molecule.
sucrose is a __ formed by condensation of __
sucrose is a disaccharide formed by condensation of a glucose molecule and a fructose molecule
maltose is a __ formed by condensation of __
maltose is a disaccharide formed by condensation of two glucose molecules
what are monosaccharides?
Monosaccharides are the monomers from which larger carbohydrates are made
What are polymers
Polymers are molecules made from a large number of monomers joined together.
Describe a condensation reaction.
-Joins two molecules together with the formation of a chemical bond
-Involves the elimination of a molecule of water.
Describe a hydrolysis reaction
-Breaks a chemical bond between two molecules
-Involves the use of a water molecule.
Describe how the structure of cellulose is related to its function(3)
-cellulose molecules are made up of b-glucose and so form long, unbranched chains
-cellulose molecular chains run parralell to each other and are cross linked by H bonds which add a collective strenght
-these molecules are grouped to form microfibriles which in turn are grouped to form fibres all of which provide more strenght
