Carbohydrates

Question 1

What is a monosaccharide?

Answer 1

A single sugar, a basic carbohydrate monomer

Question 2

What are disaccharides?

Answer 2

Dissacharides are double sugars formed from 2 monosaccharides

Question 3

What are polysaccharides

Answer 3

Complex molecules consisting of many monomers

Question 4

What is the formula for all glucose molecules

Answer 4

C6H12O6

Question 5

Draw an α-glucose molecule

Answer 5

Question 6

Draw a β-glucose molecule

Answer 6

Question 7

What is an isomer?

Answer 7

An Isomer is two substancess that have the same molecular formula but different structural formula

Question 8

Disaccharides are formed when to monosaccharides undergo a ______ reaction

Answer 8

Condensation reaction

Question 9

The disaccharide can be broken down into two monosaccharides in a _______ reaction

Answer 9

hydrolysis

Question 10

When two monosaccharides join they form a_________

Answer 10

1,4 glycosidic bond

Question 11

Two important disaccharides are:

Answer 11

Maltose= 2 alpha glucose

Sucrose= Fructose and alpha glucose

Question 12

What is the formula for disaccharides

Answer 12

C12H22O11

Question 13

What is the general formula of polysaccharides?

Answer 13

(C6H10O5)n

Question 14

The 3 polysaccharides you need to know:

Answer 14

Starch, glycogen and cellulose

Question 15

Starch

Answer 15

mixture of amylose and amylopectin.

Amylose is is many alpha glucose molecules linked by 1-4 glycosidic bonds. Unbranched

Amylopectin is many alpha glucose molecules linked by 1-4 glycosidic bonds. It is branched every ten glucose monomers and has 1-6 glycosidic bonds.

Question 16

Why is starch such a good storage molecule

Answer 16

Starch is an excellent storage molecule because:

both amylopectin and amylose are compact containing more glucoes in a small space

Insoluble in water

Being a large molecule it will not easily pass through cell membrane

The branching nature means many terminal ends which means hydrolysis can occur quicker

Question 17

Glycogen

Answer 17

Glycogen is found in animal cells and is in the form of long aplha glucose chains. They branch every 8 units.

Question 18

Why is glycogen a good storage molecule

Answer 18

compact

soluble

more terminal ends=faster hydrolysis

Question 19

Cellulose

Answer 19

Structural role, made off monomers of beta glucose;

two chains are adjacent and are anti-parallel

they form hydrogen bond cross linkages

they group together and form microfibrils

plant cell walls= microfibrils in lattice structure in improve lattice strength

Question 20

What are lipids

Answer 20

Lipids are insoluble in water byt are soluble in organic solvents

The main types of lipids are triglycerides, phosopholids

Question 21

triglycerides

Answer 21

Triglycerides are made of glycerol and a fatty acid

In each triglyceride one glycerol molecule is joined with 3 fatty acid molecules in a condensation reaction

AN ESTER BOND IS FORMED IN EACH CONDENSATION REACTION

Excellent energy store as they release more energy per unit mass than carb. Important for insulation and protection

Question 22

Saturated and unsaturated fats

Answer 22

Saturated fats= LInked by C-C single bonds

Unsaturated fats= linked by C=C double bonds (if there is one bond it is monounsaturated if there are more it is polyunsaturated)

Question 23

Fats and Oils?

Answer 23

fats=solid at RC, animal product and usually formed of saturated chains

Oils=liquid at RC, plant products and are usually formed of unsaturated chains

Question 24

Phospholipids

Answer 24

Hydrophobic tails and hydrophilic head. They are polar molecules, important for determining their orientation

Question 25

Proteins

Answer 25

Large polymers of amino acid sub-units, the amino acids determine the shape. They differ through having alternative R-groups.

they are linked by peptide bonds, joined by condesation reactions. Two peptides=dipeptide many peptides=polypeptide

Question 26

Primary, secondary, tertiary and quarternary?

Answer 26

Primary structure= Sequence of amino acids in the polypeptide chain

Secondary structure= Amino acids form hydrogen bonds and go into either alpha helix or beta-pleated sheets shapes.

Tertiary structure= Further folding of secondary structure, many bonds form: ( hydrogen bonds, ionic bonds, disulfide bonds, hydrophobic interatictions

Quarternary= Many tertiary structures bonded together. This is called a conjugated protein, e.g. haemoglobin

Question 27

Fibrous proteins

Answer 27

Collagen= 3 identical polypeptides wound round each other

Fibres

insoluble

Question 28

Globular

Answer 28

Haemoglobin is globular

form specific shapes

Question 29

Tests

Answer 29

Benedicts= carbs blue to brick red

Clinistix=glucose, turns blue

Biuret=Protein, blue to lilac

iodine= starch, yellow-brown to blue-black