Carbohydrates Flashcards
What three elements make up a carbohydrate?
Oxygen
Hydrogen
Carbon
What is a monosacaride?
1 sugar molecule
What is a disaccharide?
made of 2 monosaccarhides
What is a polysacaride>
Many monosacarides joined together.
What is the bond named in chitin?
Beta glycosidic bond
What is one similarity of the structure between chitin and cellulose?
Sugars rotated 180 degrees
What is one difference of the structure between chitin and cellulose?
OH on C2 of cellulose replacing NHCOCH2 in chitin.
How does chitin and celulose differ from starch?
( cellulose and chitin) Hydrogen bonds form to cross link adjacent polyacrylamide chains. But in starch hydrogen bonds will coil the polysaccharide to form an α helix.
What is the difference between alpha glucose and beta glucose?
α: the H is above the OH
Beta: the H is bellow the OH
Name the reaction involved when a disaccahride is formed and the type of bond formed
Condensation reaction
glycosidic bond
Give 3 examples of a monosacaride
Glucose (fruit)
Fructose (nectar)
Galactose (milk)
Give the example of the disacadirde for maltose
α glucose + α glucose = maltose
Give the example of the disaccaride sucrose
Glucose + frutose = sucrose
Give the example of the disaccaride for lactose
glucose + galactose = lactose
What is the purpose of maltose?
Germation of seeds
What is the purpose of sucrose?
Phloem tissue
What is the purpose of lactose?
Milk
What 2 polymers of alpha glucose make up starch?
-Made up of 2 polymers of α glucose: amylose and amylopection.
Insoluble in water
good storage
compound e.g. in stroma of chloroplasts
What is the structure of amylose?
- chain of glucose molecules joined by α-1,4-glycosidic bonds
- hydrogen bonding, form a helix.
- It’s this helix which holds and forms a
complex with iodine when we test for starch
What is the structure of amylopectin?
glucose molecules joined by α-1,4-glycosidic bonds
every 25 glucose molecules adjacent chains are connected by α-1,6-glycosidic
bonds i.e. amylopectin is branched.
What is the structure of glycogen?
Similar structure to amylopectin (in that it is a polymer of α-glucose) of starch
but has many more branches and the branches are shorter. Glycogen is even more
compact than amylopectin.
What is the structure of celulose?
Long unbranched chains of glucose linked by β-1,4-glycosidic bonds. The individual
chains are then linked to each other by hydrogen bonds. These are formed into
strong microfibrils.
Structure of Chitin
Made of glucosamine units (glucose + amino acid) and is linked by β-1,4-glycosidic
bonds
What is the test for starch?
1) iodine (2-3 drops)
2) Blue—> black precipitate
