Carbohydrates

Question 1

What three elements make up a carbohydrate?

Answer 1

Oxygen
Hydrogen
Carbon

Question 2

What is a monosacaride?

Answer 2

1 sugar molecule

Question 3

What is a disaccharide?

Answer 3

made of 2 monosaccarhides

Question 4

What is a polysacaride>

Answer 4

Many monosacarides joined together.

Question 5

What is the bond named in chitin?

Answer 5

Beta glycosidic bond

Question 6

What is one similarity of the structure between chitin and cellulose?

Answer 6

Sugars rotated 180 degrees

Question 7

What is one difference of the structure between chitin and cellulose?

Answer 7

OH on C2 of cellulose replacing NHCOCH2 in chitin.

Question 8

How does chitin and celulose differ from starch?

Answer 8

( 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.

Question 9

What is the difference between alpha glucose and beta glucose?

Answer 9

α: the H is above the OH

Beta: the H is bellow the OH

Question 10

Name the reaction involved when a disaccahride is formed and the type of bond formed

Answer 10

Condensation reaction

glycosidic bond

Question 11

Give 3 examples of a monosacaride

Answer 11

Glucose (fruit)
Fructose (nectar)
Galactose (milk)

Question 12

Give the example of the disacadirde for maltose

Answer 12

α glucose + α glucose = maltose

Question 13

Give the example of the disaccaride sucrose

Answer 13

Glucose + frutose = sucrose

Question 14

Give the example of the disaccaride for lactose

Answer 14

glucose + galactose = lactose

Question 15

What is the purpose of maltose?

Answer 15

Germation of seeds

Question 16

What is the purpose of sucrose?

Answer 16

Phloem tissue

Question 17

What is the purpose of lactose?

Answer 17

Milk

Question 18

What 2 polymers of alpha glucose make up starch?

Answer 18

-Made up of 2 polymers of α glucose: amylose and amylopection.
Insoluble in water
good storage
compound e.g. in stroma of chloroplasts

Question 19

What is the structure of amylose?

Answer 19

• 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

Question 20

What is the structure of amylopectin?

Answer 20

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.

Question 21

What is the structure of glycogen?

Answer 21

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.

Question 22

What is the structure of celulose?

Answer 22

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.

Question 23

Structure of Chitin

Answer 23

Made of glucosamine units (glucose + amino acid) and is linked by β-1,4-glycosidic
bonds

Question 24

What is the test for starch?

Answer 24

1) iodine (2-3 drops)

2) Blue—> black precipitate