carbohydrates

Question 1

Carbohydrates: elements, monomer, function

Answer 1

CHO, monosaccharides e.g. glucose, provides energy

Question 2

what are macromolecules

Answer 2

Macro molecules are large complex molecules with a large molecular mass
they are polymers made of similar or different molecules bonded together e.g. lipids

Question 3

explain Hydrolysis

Answer 3

A water molecule is used to hydrolyse the specific chemical bond in the two monomers which produces two separated monomers

Question 4

Definition of hydrolysis

Answer 4

Breakdown with the addition of water

Question 5

What is Condensation

Answer 5

A chemical Bonding between two molecules which produces a water molecule that is lost from the two molecules

Question 6

what is the glycosidic bond?

Answer 6

It is the covalent bond in carbohydrates found between 2 monosaccharides

Question 7

Examples of monosaccharides (one sugar)
Fruits, vegetables, honey, and nuts

Answer 7

Hexose(6 carbons) - glucose (alpha or beta) galactose fructose
Pentose(5 carbons) - deoxyribose ribose

Question 8

Examples of disaccharides (two sugar molecules linked by glycosidic bond) milk & sugar

Answer 8

Sucrose = alpha glucose + fructose
lactose = glactose + inverted beta glucose (1-4 beta glycosidic bond)
Maltose = alpha glucose + alpha glucose

Question 9

Examples of polysaccharides (many sugar molecules linked) rice, potatoes, corn wheat

Answer 9

Starch made of alpha glucose
Glycogen made of alpha glucose
Cellulose made of beta glucose

Question 10

Starch

Answer 10

• It is an energy storage molecule in plants, excess glucose from photosynthesis is stored as starch.
• It is relatively big so it’s insoluble in water so it doesn’t interfere with osmotic potential of cells.
• it contains a lot of chemical bonds which release lots of energy when broken
• is made up of two polysaccharides Amylose and amylopectin

Question 11

What is the difference between amylose and amylopectin?

Answer 11

Amylose is a long coiled chain forming a helix of alpha glucose linked by 1,4 glycosidic linkage
Amylopectin is a long branched chain of alpha glucose linked by 1,4 glycosidic linkage then 1,6 every 24 units
Combined, they give the appearance of a tightly wound molecule

Question 12

Glycogen

Answer 12

• Energy storage molecule in mammals and fungi - excess glucose from digestion is stored as glycogen.
• Insoluble in water so doesn’t interfere with osmotic potential of cells.
• more branches means it’s compact so energy dense to meet high respiratory demand and other metabolic processes like movement and digestion of large organisms e.g. animals.
• More branches also means there are more sites where enzymes attach and can hydrolyse the glycosidic bonds to release energy faster
• Consist of highly branched chains of alpha glucose with 1,4 glycosidic bonds and 1,6 glycosidic bond every 10 units which release lots of energy when broken

Question 13

How is chitin different to glycogen

Answer 13

• Is the exoskeleton of some insects
• Contains beta 1,4 glycosidic bonds
• Contains nitrogen
• No branching/ 1,6 bonds

Question 14

Cellulose

Answer 14

• Structural molecule in plant cell wall.
• Insoluble in water so doesn’t interfere with osmotic potential of cell.
• Consists of long chains of beta glucose , alternate molecules of beta glucose are inverted (because of the positioning of the OH on carbon 1 (it wouldn’t be adjacent to the OH on carbon 4 of a different molecule)) and bonded by 1-4 glycosidic bonds.
• Hydrogen bonds occur between separate straight chains of cellulose to form microfibrils that have high tensile strength and allow flexibility

Question 15

What is the monomer?

Answer 15

A small simple molecule which is produced by hydrolysis of a polymer eg monosaccharide/ amino acids / nucleotides

Question 16

What is polymer?

Answer 16

A large chain complex molecule made of similar monomers bonded together and formed by condensation

Question 17

Name the elements present in carbohydrates

Answer 17

Carbon hydrogen oxygen
(Cho) is wrong

Question 18

What is the molecular formula of a triose

Answer 18

C3H6O3

Question 19

Where is the Pentose sugar ribose found?

Answer 19

It is the sugar in RNA

Question 20

Where is the Pentose sugar deoxyribose found

Answer 20

It is the sugar in DNA

Question 21

Where is glucose found? what is it used for

Answer 21

Throughout the body as a store and it is used for energy during respiration

Question 22

Where is fructose found?

Answer 22

fruit and sweet food

Question 23

What is the general formula of a disaccharide?

Answer 23

Cn(H2O)n-1

Question 24

When the glycosidic bond is broken, which atoms would need to be replaced in order to produce complete monosaccharides?

Answer 24

O H2

Question 25

What does the prefix glyco mean?

Answer 25

Sugar

Question 26

How is fructose different from glucose? Although they are both hexose sugars?

Answer 26

Fructose has a five membered ring structure

Question 27

Name the bonds within a microfibril of cellulose

Answer 27

1,4 beta glycosidic between beta glucose, Hydrogen between two chains

Question 28

What are the properties of cellulose that make it perfect to be a plant cell wall

Answer 28

It’s insoluble Has high tensile strength Is flexible Unreactive

Question 29

Are polysaccharide soluble? Why

Answer 29

They are insoluble Because there are less free OH- groups

Question 30

Name the number of carbon atoms in the disaccharide

Answer 30

12

Question 31

How to test for reducing sugars

Answer 31

Add Benedict Regent to the sample and heat in a water bath at 100° for less than 5 mins, A positive result goes from blue to yellow/red

Question 32

Why is forming long beta glucose chains with hydrogen bonds between the chains useful for cellulose

Answer 32

it allows cellulose molecules to form strong but flexible microfibrils which provide structural support for the cell wall

Question 33

What is the advantage and disadvantage of using amylose as a storage instead of amylopectin

Answer 33

It has a coiled structure so is more compact which allows more of it to be stored in a cell but it has no 1 to 6 bonds so it is broken down slower so the glucose is less readily available

Question 34

what is the physical property of glucose that allows it to be easily transported in the bloodstream

Answer 34

its soluble in water

Question 35

what's the difference between alpha and beta glucose

Answer 35

The OH on the 1st C in beta is On top whereas in Alpha it's below

Question 36

What is the precise bond between the two glucoses to form a Maltose

Answer 36

1,4 alpha glycosidic

Question 37

Rank in an order of most soluble to lease soluble amylose ribose amylopectin glucose

Answer 37

Glucose (most FREE OH- groups) Ribose Amylose Amylopectin (has less free oh- than amylose due to branching)

Question 38

How does the structure of galactose allow it to be a good respiratory substrate?

Answer 38

Bonds in galactose contain energy which can be broken by respiratory enzymes to release energy It is soluble because of the polar OH-groups forming hydrogen bonds with water so it can be transported to where energy is needed