Carbohydrates Flashcards
(22 cards)
What are the elements in carbohydrates?
Hydrogen, oxygen and carbon
What is the general formula for carbohydrates?
CnH2nOn
What are single sugars called?
Monosaccharides
Name examples of monosaccharides
Glucose, fructose and galactose
What are double sugars called?
Disaccharides
What happens during a condensation reaction?
Condensation between two monosaccharides, involving the loss of a water molecule
Name examples of disaccharides
Glucose + glucose = Maltose
Glucose + fructose = sucrose
Glucose + galactose = lactose
The bond formed during this condensation is called….
Glycosidic bond (between carbon1 on one molecule and carbon4 on the other)
The reversible condensation reaction is called…
Hydrolysis
What are polysaccharides?
Long chains of monosaccharides joined together by glycosidic bonds (polymers)
The plant storage of carbohydrates is called…
Starch
Starch is made up of…
Amylose and amylopectin
What is the structure of amylose?
The long chains of glucose molecules coil up into a helix
What is the structure of amylopectin?
Strands of glucose molecules join in branches and thus can be broken down more easily
Animal storage of carbohydrates is…
Glycogen
What is the structure of glycogen?
(Similar to amylopectin) glucose molecules join in long branches
What is the frequency of glycogen branches?
A 1,6 glycosidic branch comes off the main chain every 4 glucose molecules
Where is glycogen found in the body and why is it found there?
Usually in the liver and muscle cells as the many branches means it is quickly broken down for releasing energy
What is a reducing sugar?
One that has an aldehyde group (CHO) so glucose, galactose, lactose and maltose
What is the test for starch?
Adding iodine changes the colour from brown to blue black when there is starch present
What is the test for reducing sugars?
Adding Benedict’s reagent and heating changes the colour from blue to brick red when there is a reducing sugar present
What is the test for non reducing sugars?
(So fructose and sucrose) initially there is a negative result when adding Benedict’s reagent. When heating with dilute acid, neutralizing and then heating with Benedict’s reagent, the brick red colour shows the presence of a non reducing sugar
