polysaccharides

Question 1

Energy storage molecule properties

Answer 1

• compact, energy dense
• insoluble so wouldn’t effect water potential
• Easy to add glucose to (condensation)
• easy to remove glucose (hydrolysis)
• metabolically inactive so will not participate in any reactions

Question 2

where is starch found and what is its function

Answer 2

found in plants, is an energy storage molecule

Question 3

What is starch made up of

Answer 3

Repeating units of glucose

Question 4

2 Types of starch molecules

Answer 4

amylose , amylopectin

Question 5

Main difference between amylose and amylopectin

Answer 5

Form different glycosidic bonds

Question 6

amylose structure and where found

Answer 6

• found in plants, stored as starch grains
• makes up 30% of starch
• A long un-branched chain of alpha glucose molecules
• Connected by 1-4 glycosidic bonds
• chain coils up on itself into a spiral shape, compact helix, held together by hydrogen bonds
• OH group is arranged on the inside of the coil, meaning its less soluble.

Question 7

Amylopectin structure and where found

Answer 7

• makes up 70% of starch , stored as starch grains
• found in plants
• chains of glucose connected by 1-4 glycosidic bonds, forming a helical shape
• Around every 25 glucose units, a 1-6 glycosidic bond is formed by condensation, creating a branch
• highly branched structure means multiple sites fro hydrolysis, allowing glucose to be removed quickly.
• this makes it denser in energy availability

Question 8

Glycogen structure and where its found and function

Answer 8

• Found in animals and fungi
• stored in the muscle and liver cells.
• an energy storage molecule
• made up of glucose
• Branched around every 10th molecule with a 1-6 glycosidic bond.

Question 9

Key properties of amylopectin and glycogen

Answer 9

insoluble, branched and compact

Question 10

extensive branching is a benefit because

Answer 10

more free ends are available for hydrolysis and condensation reactions.

Question 11

Compaction is a benefit because

Answer 11

so that many glucose units as possible can be stored for future use

Question 12

cellulose structure

Answer 12

• long, unbranched chains of β glucose
• Alternate beta glucose molecules flip forwards 180
• Form a 1-4 glycosidic bond
• No branches or coils, a straight chain bond

Question 13

Why do cellulose chains not coil into the helical shape?

Answer 13

• due to bonding
• hydrogen bonds stop it from spiralling
• hydrogen bonds form in between the chains

Question 14

what are microfibrils

Answer 14

Hydrogen bonds that have formed between the chains create microfibrils - many chains bonded together

Question 15

what are macrofibrilis

Answer 15

many microfibrils joined together

Question 16

What are fibres

Answer 16

Many macrofibrils joined together
They have high tensile strength
insoluble
pectin supports the cellulose fibres

Question 17

functions of cellulose

Answer 17

• cell wall, provides high tensile strength
• prevents cell bursting when turgid
• fully permeable, due to space between macrofibers
• insoluble
• inert

Question 18

Why is cellulose important to humans

Answer 18

Hard to break down, forms fibre which is necessary for a healthy digestive system