1.1 biological molecules carbohydrates

Question 1

what is a polymer?

Answer 1

A large molecule comprising of repeated, identical units (monomers) bonded together.

Question 2

what are monosaccharides?

Answer 2

these are monomers:
3 = triose
5 = pentose
6 = hexose

Question 3

What is the general formula for all monosaccharides?

Answer 3

Cn(H2O)n (e.g glucose C₆H₁₂O₆)

Question 4

what is the function of triose?

Answer 4

Important in metabolism. Triose sugars are intermediates in the reactions of respiration and photosynthesis.

Question 5

what is the function of pentose?

Answer 5

Constituents of nucleotides e.g. deoxyribose in DNA, ribose in RNA,ATP and ADP.

Question 6

what is the function of hexose?

Answer 6

Glucose is a hexose sugar. Glucose is a source of energy inrespiration. Carbon-hydrogen and carbon-carbon bonds are broken to release energy, which is transferred to make adenosine triphosphate (ATP).

Question 7

what is an isomer? give an example

Answer 7

An isomer is molecules with the same chemical formula but have different structures. An examples is glucose, which can be present as α glucose or β glucose.

Question 8

what are disaccharides?

Answer 8

sugars made from 2 monosaccharide units formed by a condensation reaction while joining 2 compounds

Question 9

What occurs in a hydrolysis reaction?

Answer 9

Water is chemically added to break a bond between monomers.

Question 10

What occurs in a condensation reaction?

Answer 10

Water is chemically removed to form a bond between adjacent monomers.

Question 11

glycosidic bond

Answer 11

formed by a condensation reaction in order to join two monosaccharides to create a disaccharide

Question 12

maltose

Answer 12

When two α glucose molecules are joined by condensation reaction the disaccharide maltose is formed.
-a condensation reaction occurs from the removal of C1 from 1st glucose and C4 of the second, this can be reversed by a hydrolysis reaction to break the glycosidic bond formed.
-biological role in germinating seeds

Question 13

sucrose

Answer 13

Made from the monosaccharides of glucose and fructose biological role: product of photosynthesis which is transported in the phloem

Question 14

lactose

Answer 14

Made from glucose and galactose biological role: found in mammalian milk

Question 15

What is common between all monosaccharides and some disaccharides such as maltose and sucrose?

Answer 15

all monosaccharides are reducing sugars some disaccharides are reducing sugars sucrose is a non reducing sugar

Question 16

what are polysaccharides?

Answer 16

large complex polymers. They are formed from very large numbers of identical monosaccharide units, which are their monomers

Question 17

Which properties of structural polysaccharides make them useful?

Answer 17

They are large in size so they are insoluble, they have linkages between molecules to increase strength. and they form fibres.

Question 18

What are the two main storage polysaccharides?

Answer 18

Starch (Plants) and glycogen (Animals)

Question 19

starch

Answer 19

Found in plants only and allows them to store glucose. Made up of α glucose monomers, added one at a time by condensation reaction. Starch has two types of polysaccharide: amylose and amylopectin.

Question 20

Amylose

Answer 20

Amylose is unbranched and coils; each α glucose monomer added forms a C1 - C4 glycosidic bond with the adjacent glucose molecule.
forms a helix shape

Question 21

Amylopectin

Answer 21

Amylopectin is branched, each branch point is formed by a C1 - C6 glycosidic bond.

Question 22

Why is starch a good storage molecule?

Answer 22

They are osmotically inactive (don’t effect water potential of cell)compact molecule: large amount stored in small space

Question 23

Which polysccharide is used to store glucose in animals and is especially found in muscle cells? What type of glycosidic bonds does it use?

Answer 23

Glycogen uses both 1,4 and 1,6 glycosidic bonds but has more branches than amylopectin for hydrolysis and therefore quicker energy release. glycogen is turgid because there is no cell wall

Question 24

Cellulose

Answer 24

structural polysaccharide found in plant cell walls. Cellulose consists of many long, parallel chains of β glucose units which are joined by C1 - C4 glycosidic bonds. The β bond rotates adjacent glucose molecules by 180º

Question 25

Why is it important that the β glucose is arranged in 180° rotations?

Answer 25

This allows hydrogen bonds to form between adjacent cellulose molecules - this increases the strength of the molecule

Question 26

What do many chains of cellulose create and what are it’s uses?

Answer 26

Microfibrils are bunched together in bundles to form fibres. Cellulose is unreactive and stable (due to being unbranched) and has a high tensile strength that’s used in plant cell walls (due to the formation of microfibrils and fibres).

Question 27

Chitin

Answer 27

-Made of β glucose
-Rotates 180° from previous molecule
-Hydrogen bonds between chains
-Differs from cellulose in that each monomer has a group derived from amino acids added, called an acetylamine group.
-The cross-linked parallel chains form microfibrils.
-Exoskeleton in insects + fungal cell wall

Question 28

Name one property of chitin and how this can be used.

Answer 28

Chitin is strong and lightweight, useful as exoskeletons of insects