Amino acids Flashcards Preview

Organic chemistry and synthesis A2 > Amino acids > Flashcards

Flashcards in Amino acids Deck (28):
1

What functional groups does an amino acid contain?

Amino group and carboxylic acid group

2

Amino acids can combine in what type of reaction?

A condensationreaction

3

If 2 amino acids combine what is produced?

A dipeptide

4

If 2 different types of amino acids combine what will be produced?

2 different types of dipeptide

5

What is produced when more than 2 amino acids combine?

A polypeptide which leads to protein formation

6

What does R represent in...
Glycine (2-aminoethanoicacid)
Alanine (2-aminopropanoicacid)
Serine (2-amino-3-hydroxypropanoicacid)

Glycine- H
Alanine- CH3
Serine- CH2OH

7

What is a primary protein structure?

The precise sequence of amino acids in the protein chain - many sequences with different amino acids

8

What is. Secondary protein structure

How parts of the protein fold up to form an alpha helix (held in shape by hydrogen bonds involving peptide link) or a beta pleated sheet (paper shape stabilised by hydrogen bonds between amino acids in different polypeptide chains)

Results in hydrogen bonding
Occurs between N-H and C=O groups of polypeptide chains

9

What is a tertiary protein structure

Proteins as a whole and the way in which alpha helices and beta pleated sheets of protein fold with respect to eachother

This structure is held together by interactions eg
Intramolecular- covalent and ionic bonds
Intermolecular - VDW and H bonds

10

Draw acids hydrolysis of peptide/amide link

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11

Draw alkaline hydrolysis of peptide/amide link

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12

What do amino acids predominantly exist as and what are these?

Zwitterions: these are internal sales and neutral molecules

13

Draw a zwitterion

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14

Draw the zwitterionic nature of amino acids in acidic conditions

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15

Draw the zwitterionic nature of amino acids in alkaline conditions

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16

What are the properties of amino acids?

High melting points- have strong ionic bonding (IMF) lots of energy to overcome bonding and melt

Soluble in water due to ionic properties

17

Reaction of amino acids with ethanoyl chloride

Has to be done in a fume cupboard as hydrogen chloride produced

Dry conditions

Produces:

CH3CONHCHRCOOH

18

Structure of an amino acid

NH2CH(R)COOH

19

How to make an amino acid into a zwitterion

Remove the far end H and put it into the N instead

20

How does a secondary structure arise from a primary?

From hydrogen bonding between N-H groups in one part and C=O groups in Another part- this is due to parts of the protein folding to form an alpha helix or a beta pleated sheet

21

Explain importance of proteins in living systems

Cotton fibres contain protein fibres

Essential in all living matter eg muscle

Enzymes are made up of them- biocatalysts in living cells carry out complex reactions. They're sensitive to changes in Temp and pH

22

Why do amino acids have high MPS?

They have strong ionic bonding(IMF) lots of energy needed to overcome bonding and melt them

23

What happens to the structure of a zwitterion under acidic conditions?

Why?

The carboxyl group is removed and replaced with a hydroxy group (OH)

Because the zwitterion acts as a base under acidic conditions so accepts H+

24

What does the zwitterion act as under acidic conditions?

A base- accepts H+

25

What happens to the structure of zwitterion under alkaline conditions?

Why?

A H is removed

Because under alkaline conditions the zwitterion acts as a acid so donates H+

26

What happens to structure of an amino acid in formation of a zwitterion?

a H is moved from the end to the N

Positive charge put in the N
Negative charge on the Oxygen that's left on the end

27

What is a zwitterion

An internal salt which is a neutral molecule

28

If you have a secondary protein structure: what bonding will occur between molecules?

Hydrogen bonds