Organic Synthesis,NMR And Amino acids

Question 1

What do amino acid molecules consist of and what property do they share

Answer 1

An amine group
A carboxylic acid group

They are all chiral

Question 2

State the properties that the carboxylic acid and amine group have in Amino acid and state what they react with

Answer 2

Carboxylic acid has acidic properties and so react with bases

Amines have basic properties and react with acids

Question 3

What would happen when the amino acid is in a high ph(alkali)

Answer 3

The COOH would lose a hydrogen and become

COO-

Question 4

What would happen when the amino acid is in a low ph (reacts with acids)

Answer 4

The Nh2 would gain a hydrogen

Becomes NH3+

Question 5

What is is called when amino acid reacts with itself

Answer 5

It’s referred to an a zwitterion they have both a proton donar(COOH)and proton accepting group(NH3)

NH3 +
COO-

Question 6

State the bond that forms between amino acids in a protein

Answer 6

Peptide bonds

Question 7

What is the primary structure of a proteins

Answer 7

The sequence of amino acids in a chain

Question 8

What are the two secondary structures proteins can form

Answer 8

A helix

Beta plated sheets

Question 9

State why secondary structures can occur in proteins

Answer 9

As hydrogen bonds can occur between the hydrogen atom on peptide link with either a nitrogen or oxygen on another peptide link

Question 10

What is the tertiary structure and how does it occur

Answer 10

The 3D structure of a protein it occurs as a result of interactions between amino acid groups further apart in the chain

Question 11

State the 3 types of bonds that can form in the tertiary structure

Answer 11

Hydrogen bondings
Ionic bonding
Covalent sulfur Sulfur bonds (disulphides Bridge

Question 12

What are the 4 bases in DNA

Answer 12

Adenine
Cytosine
Guanine
Thymine

Question 13

What is DNA made up of

Answer 13

Phosphate ion
2-deoxyribose
One of the four bases(adenine,cystine,guanine,thymine)

Question 14

State the complementary bonding in DNA

Answer 14

Thymine pairs with adenine

Cytosine pairs with Guanine

Question 15

When a condensation reaction occurs between two nucleotides what is formed and where does the bond occur

Answer 15

It occurs between the phosphate group of one nucleotide and the deoxyribose of another it’s a covalent bond

Question 16

What is the function of cisplatin and give its structure

Answer 16

It’s anti-cancer drug

• 2(Cl)-Pt-(NH3)2

Question 17

How does cisplatin work

Answer 17

It binds to two of the Guanine bases on a strand of DNA

It undergos ligand substitution with with the Nitrogen on Guanine replacing the CL on the cisplatin and a dative covalent bond forms

This action prevents cell replication of the DNA which means cancer cells can no longer divide

Question 18

Why does the Nitrogen atom on the cisplatin replace the Chlorine on the cisplatin

Answer 18

As it’s a better ligand

Question 19

State why cancer drugs like cisplatin have side effects

Answer 19

Because it binds to DNA in healthy cells preventing them from replicating and so as a result people may lose their hair

Question 20

What are enzymes

Answer 20

That are globular proteins that catalyse reactions

Question 21

What part of an enzyme catalyses reaction

Answer 21

It’s active side

Question 22

Why are enzymes considered to be stereospefic

Answer 22

As their 3D shapes can only catalyse one individual enantiomer or pair of a chiral molecule

Question 23

What happens in enzyme inhibition.

Answer 23

drugs are designed that have a similar shape to the substrate,

It will bind to the active site of the enzyme blocking the substrate from binding it preventing a reaction occurring so the reaction won’t occur

Question 24

Why are computer models becoming useful in treating enzymes

Answer 24

They can predict the shape of the enzyme and once the shape is understood then they can design the shape of the substrate that can react with the enzyme

Question 25

Why is enzyme inhibition useful

Answer 25

As we can prevent the reaction of enzymes that may cause harmful reactions in our body

Question 26

State how the structures in a protein can be identified and give the name of the process and the reagent involved

Answer 26

By hydrolysis using 6 mol dm of hydrochloric acid

This breaks the amide bond in the protein

Question 27

Why is TMS used as standard and state it’s formula

Answer 27

It’s inert

Non-toxic
Low melting point so it
can be removed easily

Produces a single peak as all the hydrogens are chemically equivalent
Produces an intense peak

Si(ch3)4

Question 28

What is the standard used in proton nmr and why it is useful

Answer 28

CCl4,CDCL3 is the isotope

Contains no hydrogens atoms

Question 29

What is the advantages of Tlc over papar chromatography

Answer 29

It runs faster
Smaller amounts of mixture can be separated
Spots spread out less

Question 30

What is the mobile phase in chromatography

Answer 30

It’s carries the soluble components of the mixture with it

Question 31

Give the 3 types of chromatography

Answer 31

Thin layer chromatography

Column chromatography

Gas chromatography

Question 32

What happens in column chromatography

Answer 32

A glass tube (which is the column) is filled with the stationary phase (slica)in powder form to increase the surface area

A filter is used to retain the solid in the tube

The mixture to be analysed is to be dissolved in the solvent and is then add EE to the column

The solvent is then run through the column

The time for each component in the mixture to reach the column is recorded

Question 33

What is retention time and why is it useful

Answer 33

The time for each component to reach the end of the mixture

It can be used to identify a component

Question 34

What happens in gas chromatography

Answer 34

A gaseous mixture is injected into a column and is allowed to flow through under high pressure

The time it takes to control exit the coloumn is called retention time and can be used to identify the component

Question 35

In gas chromatography what is the mobile phase and stationary phase

Answer 35

Gas like helium

A liquid with a high boiling point

Question 36

State how haloalkane are formed

Answer 36

From electrophillic addition of alkenes

Question 37

State what the splitting patterns

Singlet
Doublet
Triplet
Quartet dhow

Answer 37

Singlet-shows that the adjacent carbon has no hydrogen attached(indicating possible functional group)

Doublet shows the adjacent carbon has 1 hydrogens

Triplet shows that the adjacent carbon has 2 hydrogens

Quartet shows that the adjacent carbon has 3 hydrogens attached

Question 38

What do the amount of peaks on carbon nmr tell us

Answer 38

The number of different environments carbon is in