Carbohydrates

Question 1

What are Carbohydrates made up of?

Answer 1

Carbon
Hydrogen
Oxygen
Made from monosaccharides, simple sugars containing three to seven carbon atoms

Question 2

Monosaccharides: Example

Answer 2

Glucose
Galactose
Fructose

Question 3

What is Glucose?

Answer 3

A hexose sugar - C6 H12 O6
An important source of energy in humans
During cellular respiration, the energy released from glucose helps to make adenosine triphosphate ( ATP )

Question 4

Isomers of glucose

Answer 4

Alpha
Beta
Isomers have the same molecular formula but different structural formula
The carbon atoms are numbered from 1-6 and the OH (hydroxyl) groups are in a different orientation around C1

Question 5

Glucose + Glucose

Answer 5

Maltose

Question 6

Glucose + Fructose

Answer 6

Sucrose

Question 7

Glucose + Galactose

Answer 7

Lactose

Question 8

What are Polysaccharides made up of?

Answer 8

Polysaccharides are made up of three or more monosaccharides joined together by glycosidic bonds.
The chain may be branched or unbranched
The chain may contain different types of monosaccharides

Question 9

Polysaccharides: Examples

Answer 9

Starch
Glycogen
Cellulose
Chitin

Question 10

What do Straight chain polysaccharides consist of?

Answer 10

Beta glucose
Beta- 1,4- bonds

Question 11

What do coiled chain polysaccharides consist of?

Answer 11

Alpha glucose
Alpha-1,4- bonds

Question 12

What do coiled branched chain polysaccharides consist of?

Answer 12

Alpha- 1,6 - glycosidic bonds
Alpha- 1,4 - glycosidic bonds

Question 13

what type of polysaccharide is cellulose?

Answer 13

long, straight polysaccharide

Question 14

what is cellulose made up of?

Answer 14

Beta-1,4- glycosidic bonds

Question 15

Why does cellulose provide the plant cell wall with structure?

Answer 15

The straight linear cellulose chains lie parallel to each other, resulting fin hydrogen bonds forming between them. Although, individually, hydrogen bonds are weak intermolecular forces, together they are strong adding to the rigidity of the cellulose. The grouped chains are called microfibrils. Many parallel microfibrils are called macrofibrils. Many macrofibrils make up the plant cell wall.

Question 16

what is glycogens main function?

Answer 16

energy storage molecule in animals

Question 17

how is glycogen adapted to its role as an energy storage molecule?

Answer 17

It cannot cross cell membrane as it is too large
It is compact due to its coiled nature
It doesn’t affect water potential as it is insoluble

Question 18

what is starch’s main function?

Answer 18

Energy storage in plants

Question 19

Where is glycogen stored?

Answer 19

in liver and muscle cells

Question 20

where is starch stored?

Answer 20

As granules in plastids such as chloroplasts

Question 21

what is starch constructed from?

Answer 21

Amylose: 10-30%
unbranched helix-shaped chain with 1,4 glycosidic bonds between a-glucose molecules
the helix shape enables it to be more compact and thus resistant to digestion.

Amylopectin: 70-90%
1,4 glycosidic bonds between a-glucose molecules
1,6 glycosidic bonds between glucose molecules creating branches
the branches result in many terminal glucose molecules that can be easily hydrolysed during cellular respiration

Question 22

which saccharides are reducing sugars?

Answer 22

some disaccharides
some polysaccharides
all monosaccharides

Question 23

which saccharides are non reducing sugars?

Answer 23

disaccharides
polysaccharides

Question 24

Reducing Sugars: Examples

Answer 24

monosaccharides:
glucose
fructose
galactose

disaccharides:
maltose
lactose

Question 25

Non reducing sugar: Example

Answer 25

Sucrose

Question 26

A student applied the Benedict’s test to a sample. The resulting solution has a colour somewhere between blue and orange- brown.
The student wants a quantitative measure to represent how much reducing sugar was present in their testing sample.

Answer 26

Filter the solution for orange- brown precipitate, then dry the precipitate and measure it’s mass.