Carbohydrates Flashcards
What are polymers?
Large, complex molecules composed of long chains of monomers joined together.
What are monomers?
Monomers are small, basic molecular units.
What are some examples of monomers?
monosaccharides, amino acids and nucleotides
What elements do all carbohydrates contain?
C, H and O
What are the monosaccharides that carbohydrates and made from called?
glucose, fructose, galactose
How many carbons does glucose contain?
6 - it is a hexose sugar
What is the diffrence between alpha glucose and beta glucose?
they have a diffrent arrangement of atoms. they have the H and OH, group reversed. H on top for alpha on rightside, OH on top for beta on the riightside.
What is a condensation reaction?
two molecules join together with the formation of a new chemical bond, and a water molecule is realeased.
How are Monosaccharides join together?
condensation reaction
What is the bond called between to monosaccharides?
Glycosidic bond
What is formed when two monosaccharides join together?
A disaccharide
What do two molecules of alpha glucose form when joined up?
maltose
What does fructose and glucose form when joined ?
Sucrose
What does glucose and galactose form when joined?
Lactose
How are polymers broken back down to monomers?
By a hydrolysis reaction
What is a hydrolysis reaction?
Hydrolysis reaction breaks the chemical bond between monomers using a water molecule.
What test is used for sugars?
Benedicts reagent
What sugars are reducing sugars?
All monosaccharides and some disaccharides
What do you do after adding benedicts reagent to a sample?
heat it in a water bath that been brought to the boil.
What would happen if the test is positive for a reducing sugar?
the sample will turn coloured brick red or orange
If the result for reducing sugars is negative what can you do?
a test for non reducing sugars
How do you break up the sample into monosaccharides?
add dilute HCl and carefully heat it in a water bath thats been brought to boil. you can nuetralise it with sodium hydrogencarbonate.
What do you do after you break up the monosaccharides in a non reducing sugar test?
carry out benedicts test normally
How would you do if the test is postive for a non reducing sugar?
it will form a coloured precipitate, if the test is negative the solution will stay blue which means it does not contain a sugar( either reducing or non reducing).
