Monosacchrides and disacchrides

Question 1

What is a monosaccharide?

Answer 1

It contains a single monomer, e.g, glucose, fructose and galactose

Question 2

What is a disaccharide?

Answer 2

It contains two monomers joined together, e.g, maltose (2 alpha glucose molecules), sucrose (glucose and fructose) and lactose (glucose and galactose)

Question 3

What is a polysaccharide?

Answer 3

It contains many monomers joined together, e.g, starch, cellulose and glycogen (all made of glucose joined together)

Question 4

What are the uses of carbohydrates?

Answer 4

They make up 10% of a cells organic matter and are an energy source for respiration. Starch (in plants) and glycogen (in animals) are energy stores and cellulose is used for structure in plant cell walls

Question 5

What are the elements in a carbohydrate?

Answer 5

Carbon, hydrogen and oxygen

Question 6

What is a triose monosaccharide?

Answer 6

It is a monosaccharide made of 3 carbon sugars and it’s biological importance is intermediate in respiration, e.g, triose phosphate

Question 7

What is a pentose monosaccharide?

Answer 7

A monosaccharide made of 5 carbon sugars and it’s biological importance is in nucleic acids (DNA and RNA), e.g, ribose

Question 8

What is a hexose monosaccharide?

Answer 8

A monosaccharide made of 6 carbon sugars and it’s biological importance is respiratory substrates and blood sugar, e.g, glucose

Question 9

Why are hexose monosaccharides soluble in water?

Answer 9

They are polar as the hydroxyl (OH) groups are slightly positive, forming hydrogen bonds between the hydroxyl groups and water molecules. This is important and it allows glucose to dissolve in the cytoplasm and blood stream.

Question 10

What are the two forms of glucose?

Answer 10

Alpha and beta glucose. In beta glucose, the OH is above carbon - 1

Question 11

What does beta glucose form?

Answer 11

Only cellulose, allowing for a structural polysaccharide

Question 12

What does alpha glucose form?

Answer 12

Other polysaccharides such as starch

Question 13

What are the two ways glucose can be drawn?

Answer 13

In a ring or a chain

Question 14

What is furanose?

Answer 14

A ring with 5 members?

Question 15

What is pyranose?

Answer 15

A ring with 6 members

Question 16

What are the properties of fructose?

Answer 16

It is sweeter than glucose and is found in fruit and sugar

Question 17

What are the properties of galactose?

Answer 17

It is sweeter than fructose and is found in milk and dairy products

Question 18

What is an isomer?

Answer 18

Molecules with the same chemical formula but have different molecular arrangements, such as alpha and beta glucose or fructose and galactose

Question 19

How are monosaccharides joined together?

Answer 19

They are joined by a condensation reaction where water is removed from the bond

Question 20

What is a glycosidic bond?

Answer 20

When two monosaccharides are joined together to form a disaccharide

Question 21

What kind of bond is between 2 alpha glucose molecules?

Answer 21

An alpha 1,4 glycosidic bond

Question 22

Where is maltose found?

Answer 22

It is found in germinating grains

Question 23

Where is sucrose found?

Answer 23

It is found in fruit and cane sugar

Question 24

Where is lactose found?

Answer 24

It is found in milk

Question 25

How are carbohydrates broken down in digestion?

Answer 25

Larger molecules are broken down by enzymes breaking the glycosidic bond between the monosaccharides through hydrolysis which adds water to break them.