Carbohydrates

Question 1

Monomers

Answer 1

Small, single units that act as building blocks to make larger molecules

Question 2

Polymers

Answer 2

Made up of many monomers, usually thousands, chemically bonded together in chains

Question 3

Condensation reactions

Answer 3

Involves the removal of a water molecule. This removal of water from the monomers enables a chemical bond to form between the monomers

Question 4

Hydrolysis reaction

Answer 4

A water molecule is added between 2 bonded monomers to break the chemical bond

Question 5

Monomers->polymers

Answer 5

Nucleotides(RNA and DNA)->polynucleotides
Monosaccharides->polysaccharides
Amino acids->polypeptides

Question 6

Carbohydrates

Answer 6

Store energy and can provide structural support to plants
Contain carbon, hydrogen and oxygen

Question 7

What are the 3 types of carbohydrates?

Answer 7

Monosaccharides, disaccharides and polysaccharides

Question 8

Monosaccharides

Answer 8

The monomers of carbohydrates eg glucose, galactose and fructose
They are sugars that are soluble in water which either provide energy or are building blocks to create larger molecules
General formula=cnh2n0n

Question 9

Glucose

Answer 9

C6H12O6- a monosaccharide that can provide energy or be polymerised to form a structural support molecule(cellulose) or an energy storage molecule(glycogen and starch)

Question 10

Alpha and beta glucose

Answer 10

Glucose has 2 structural isomers. Isomers are structures that have the same formula but the atoms are arranged differently. The difference in alpha and beta glucose is the hydrogen and hydroxyl group on carbon 1 swap positions ( OH is above in beta glucose) this has a significant impact on bonding and the polymers that they form

Question 11

Disaccharides

Answer 11

2 monosaccharides bonded together by a glycosidic bond that is formed by a condensation reaction

Question 12

Maltose

Answer 12

2 alpha glucoses

Question 13

Sucrose

Answer 13

Alpha glucose and fructose

Question 14

Lactose

Answer 14

Beta glucose and galactose

Question 15

Polysaccharides

Answer 15

Polymers made up of many monosaccharides via condensation reaction

Question 16

Starch

Answer 16

Found in plants not animals and is the major carbohydrate store. Starch is made from the excess glucose created in photosynthesis. Glucose is used in respiration but if more glucose is created in photosynthesis than needed, it is converted to the polymer starch for storage

Question 17

The structure of starch

Answer 17

Starch is a polymer made of alpha glucose which are joined together via condensation reactions and held in place by 1,4 and 1,6 glycosidic bonds
Starch is made up of 2 polymers -amylose and amylopectin

Question 18

Amylose

Answer 18

The glucose monomers are joined together by 1,4 glycosidic bonds. This results in a spiral shaped polymer which means it can be readily compacted

Question 19

Amylopectin

Answer 19

The glucose monomers are joined by a combo of 1,4 and 1,6 glycosidic bonds. The 1,6 glycosidic bonds result in branches which provide a larger surface area for enzymes to attach to. This means that starch is readily hydrolysed back into glucose when plant cells are running low on glucose for respiration

Question 20

Properties of starch

Answer 20

Starch is insoluble as it is a large molecule. This is an advantage as it can be stored in cells and not dissolve. Therefore it will not change the water potential and not cause osmosis to occur.

Question 21

Glycogen

Answer 21

The major carbohydrate storage molecule found in animal cells mostly in the liver and muscle.

Question 22

Making glycogen

Answer 22

Made from excess glucose that has been eaten and absorbed into the blood stream. If more glucose is eaten than the cells use for respiration it is converted to the polymer glycogen for storage

Question 23

Storing glycogen

Answer 23

As liver called are responsible for removing toxins and muscle cells are responsible for movement, glycogen is mainly stored in these cells to ensure they always have access to glucose to respire and release energy

Question 24

Structure of glycogen

Answer 24

Glycogen is a polymer made up of alpha glucose and is very similar to the structure of amylopectin in starch. The alpha glucose molecules are joined together via condensation reactions and are held in place by 1,4 and 1,6 glycosidic bonds. Glycogen contains more 1,6 glycosidic bonds than amylopectin, therefore a more branched structure.

Question 25

Properties of glycogen

Answer 25

Glycogen is insoluble as it is a large molecule. This is an advantage as it can be stored in cells without dissolving. Therefore it will not change the water potential of a cell nor cause osmosis, which would otherwise cause cell lysis

Question 26

Properties of glycogen 2

Answer 26

Glycogen is a highly branched molecule which means it had a large surface area for enzymes to attach. This means that it is readily hydrolysed into glucose when cells are low. Glycogen is even more branched than starch, therefore it can be hydrolysed back into glucose more rapidly which is essential for animals as they have a higher metabolic rate and need more glucose

Question 27

Function of cellulose

Answer 27

To provide structural strength in plants. Cellulose is located in the cell wall of plants and therefore prevents cell from bursting if they take in excess water

Question 28

Structure of cellulose

Answer 28

The only polysaccharide made up of beta glucose with monomers joined together by 1,4 glycosidic bonds. So the cellulose polymer is unbranched. These long, straight chains of beta glucose accumulate and lie parallel to each other and held together by many hydrogen bonds and the sheer number of hydrogen bonds provides strength.
This structure is called a fibril. Fibrillation then align in parallel and are held in place by even more hydrogen bonds to form cellulose fibres