1.2 Biological Molecules 1

Question 1

How is sucrose made and what is its source?

Answer 1

It’s is made from alpha glucose and fructose
It is stored in plants such as sugar cane

Question 2

How is lactose made and what is its source?

Answer 2

Alpha glucose and beta galactose
Found in milk sugar

Question 3

How is maltose made and what is its source?

Answer 3

Alpha glucose and alpha glucose
Found in malt sugar

Question 4

What is a condensation reaction?

Answer 4

A reaction in which a molecule of water is removed from the reacting molecule and a bond is formed between them

Question 5

What bond is formed when 2 monosaccharides join together?

Answer 5

Glycosidic bond

Question 6

What is hydrolysis?

Answer 6

Reaction in which bonds are broken with the addition of water

Question 7

What is starch and what is it made up of?

Answer 7

Energy store in plants
Made up of amylose and amylopectin

Question 8

Describe the structure of amylose and how is it adapted to its function?

Answer 8

Long Unbranched polymer
Made up of alpha glucose molecules which are joined by 1,4 glycosidic bonds
As chain lengthens molecule spirals and turns into a helical shape making it more compact for storage

Question 9

Describe the structure of amylopectin and how it is related to its function?

Answer 9

Branched polymer of glucose molecules
Contain 1,4 and 1,6 glycosidic bonds
This results in branching chains which have any terminal glucose molecules that can be broken rapidly when energy is needed.

Question 10

Describe the structure of glycogen and how it is related to its function?

Answer 10

Similar to amylopectin
Contains glucose molecules which are joined by 1,4 and 1,6 glycosidic bonds
Compact for energy store
1,6 glycosidic bonds for rapid breakdown of glucose molecules

Question 11

Describe the structure of cellulose and how it is related to its function?

Answer 11

Usually seen in plant cell walls
Made up of many beta glucose monomers where every other monomer is inverted and held by 1,4 glycosidic bonds
Hydrogen bonds are bale to be formed which hold the molecules/chains/layers together
Very long, straight chains
Strong to prevent cells from bursting

Question 12

What is the difference between saturated fatty acids and unsaturated fatty acids?

Answer 12

Saturated = contains only single covalent bonds
Unsaturated = contains one or more double covalent bonds

Question 13

How is a triglyceride formed and what bond does it contain?

Answer 13

Formed via a condensation reaction with a glycerol molecule and 3 fatty acid molecules
Contains an ester bond (esterification)

Question 14

Explain the arrangement of phospholipids in a membrane.

Answer 14

They are arranged in a bilayer format
They have hydrophilic/polar/phosphate heads that are orientated outside as they can interact with aqueous environment
They have fatty acid/non-polar/hydrophobic tails within the membrane because they turn away from the water

Question 15

What bond is formed when 2 amino acids join together?

Answer 15

Peptide bond

Question 16

What other bonds are formed alongside a peptide bond?

Answer 16

Hydrogen bonds
Disulfide bonds
Ionic bonds

Question 17

Describe the primary structure of a protein.

Answer 17

The linear sequence of amino acids in a peptide

Question 18

Describe the secondary structure of a protein.

Answer 18

The folding of the primary structure
Into an alpha helix or beta pleated sheet
Due to the formation of hydrogen bonds

Question 19

Describe the tertiary structure of a protein.

Answer 19

The 3-Dimensional folding of the secondary structure

Question 20

Describe the quaternary structure of a protein.

Answer 20

The 3-Dimensional arrangement of more than one tertiary polypeptide

Question 21

Describe the structure of a fibrous protein.

Answer 21

Little or no tertiary structure
Insoluble
Made up of long polypeptide chains with cross linkages

Question 22

Describe the structure of a globular protein.

Answer 22

Has a tertiary structure
It is held by disulfide bonds
Have hydrophilic r groups on the outside of the molecule and hydrophobic r groups in the centre of the structure

Question 23

Describe the structure of collagen and how it is related to its function?

Answer 23

Contains 3 polypeptide chains
That are left hand helices joined together
The helices are hold together by hydrogen bonds
There are triple helices joined together - found together in microfibrils that help make the molecule strong

Question 24

Describe the structure of Haemoglobin and how it is related to its function?

Answer 24

Quaternary protein structure
Made up of 4 polypeptide chains containing a haem group
Held together by disulfide bonds
The arrangement determines how easily the oxygen binds or is released