Unit 2 - Biological Molecules

Question 1

Three Monosaccharides

Answer 1

Glucose
Fructose
Galactose

Question 2

Three Disaccharides

Answer 2

Sucrose
Maltose
Lactose

Question 3

Three Polysaccharides

Answer 3

Starch
Cellulose
Glycogen

Question 4

What’s the difference between alpha and beta glucose?

Answer 4

Alpha glucose has the hydroxide is on the bottom and the hydrogen on the top. Opposite for beta

Question 5

define disaccharide [3]

Answer 5

Made of two monosaccharides
joined together by a glycosidic bond
formed by a condensation reaction

Question 6

What monomer is starch made from?

Answer 6

alpha glucose

Question 6

What monomer is cellulose made from?

Answer 6

beta glucose

Question 7

What monomer is glycogen made from?

Answer 7

alpha glucose

Question 8

Which polysaccharides have 1-4 and 1-6 glycosidic bonds?

Answer 8

Amylopectin (starch) and Glycogen

Question 9

Which polysaccharide have 1-4 glycosidic bonds?

Answer 9

Cellulose

Question 10

What is a feature of all polysaccharides?

Answer 10

They are large and insoluble - they won’t affect water potential

Question 11

What’s an advantage of the 1-6 glycosidic bond?

Answer 11

It has many branches and therefore and large surface area for rapid hydrolysis back to glucose

Question 12

The two types of lipids

Answer 12

Triglycerides and Phospholipids

Question 13

What is the structure of a triglyceride?

Answer 13

one glycerol and three fatty acids

Question 14

what is the structure of a phospholipid?

Answer 14

a glycerol backbone
attached to 2 hydrophobic fatty acid tails
and one hydrophilic polar phosphate head

Question 15

How are triglycerides formed?

Answer 15

Via condensation between one molecule of glycerol and three molecules of fatty acid

Question 16

What is the bond in tryglycerides called?

Answer 16

ester bond

Question 17

What’s the difference between saturated and unsaturated fatty acids

Answer 17

saturated fatty acids only have single bonds between carbons while unsaturated fatty acids have double bonds between carbons

Question 18

how are polymers made?

Answer 18

by joining smaller molecules with covalent bonds

Question 19

what type of sugar is sucrose

Answer 19

non reducing

Question 20

what type of sugars are glucose, fructose and maltose

Answer 20

reducing

Question 21

How do you test for a non reducing sugar? [3]

Answer 21

Boil test sample with HCI
Neutralise with nAHCO
Add Benedict’s solution to sample, then heat over water bath

Question 22

Define macromolecule

Answer 22

A large molecule formed by condensation reactions between smaller molecules.

Question 23

define monomer

Answer 23

a single used to build larger polymers

Question 24

how are glycosidic bonds broken?

Answer 24

water is used to break the bond in hydrolysis

Question 25

function of phospholipids

Answer 25

forms phospholipid bilayer in water - the hydrophobic tails allow for control of movement of water soluble molecules in and out of the cell

Question 26

describe common structure of an amino acid [4]

Answer 26

• Amine group (-NH2)
• Variable side chain (R)
• Carboxyl Group (-COOH)
• H atom

Question 27

how are peptide bonds formed?

Answer 27

OH is lost from the carboxyl group and a H from the amine group

Question 28

structure of a primary protein

Answer 28

a sequence of amino acids in a polypeptide held by peptide bonds

Question 29

secondary structure

Answer 29

the regular folding of a polypeptide into alpha helixes and beta pleated sheets held together by hydrogen bonds

Question 30

tertiary structure

Answer 30

further coiling of a protein into its functional 3d shape. Held by hydrogen, ionic and disulphide binds and hydrophobic interactions

Question 31

quaternary structure

Answer 31

the folding of 2 or more polypeptides into a 3d shape, which may include prosthetic (non protein) groups. held together by hydrogen, ionic and disulphide bonds and hydrophobic interactions

Question 32

describe globular proteins

Answer 32

generally soluble
have physiological roles

Question 33

describe fibrous proteins

Answer 33

• insoluble
• structural role