Amino acids, amides, chirality

Question 1

What two functional groups do all amino acids have

Question 2

What is the general formula for amino acids?

Answer 2

R-CH(NH2)-COOH (except from proline)

Question 3

What are a-amino acids?

Answer 3

the amino and carboxyl groups are on the same carbon atom

Question 4

how do you name amino acids?

Answer 4

amino…..acid

Question 5

What are the functional groups on an amide?

Answer 5

an acidic carboxyl group and a basic amine group.
Treat each functional group as a separate reacting centre

Question 6

What does the amine group react with?

Answer 6

The amine group is basic and can react with acids and become protonated.
H2N becomes H3N+ (+ion)

Question 7

What does the carboxyl group react with?

Answer 7

The carboxyl group is acidic and can react with bases. The –COOH group is deprotonated.
H gets removed from cooh and h2o forms (COOH—>COO-)

Question 8

What can the carboxylic function group react with?

Answer 8

alcohols in the presence of conc sulphuric acid to produce an ester.
O gets removed from OH and H gets removed from adjacent c to on one it’s on
h on cooh gets replaced by left over ch….
h2O formed

Question 9

What is a peptide bond?

Answer 9

the specific name for the amide bond that forms when alpha amino
acids react

Question 10

How do amino acids react together?

Answer 10

with the elimination of a water molecule to form a peptide (or amide) bond.
This is called a condensation reaction because a small molecule (water in
this case) is formed.
When two amino acids react together a dipeptide is made.

Question 11

How are proteins and polypeptides formed?

Answer 11

by many condensation polymerisations involving the
loss of water.

Question 12

What is a polypeptide?

Answer 12

a peptide containing more than 3 amino acid molecules (monomers)

Question 13

What is a protein?

Answer 13

a chain of 40 or more amino acids linked together by peptide linkages

Question 14

What must I do when drawing amino acids coming together by condensation reactions?

Answer 14

must start/end with NH2 or OH

Question 15

what is hydrolysis?

Answer 15

This term means the splitting of water by reaction with another compound. It means the other compound also gets split.
If you split a protein you produce amino acids.

Question 16

What does the hydrolysis of a protein require?

Answer 16

heating in aqueous acid or aqueous alkali conditions (in the body, enzymes are involved).

Question 17

What happens in acid hydrolysis?

Answer 17

(+H2O + 2H+)
-bond splits between first Nh2 and o=
-o becomes oh
-both Nh2 become nh3+
-we get the protonated form of the amino group here

Question 18

what happens in base hydrolysis?

Answer 18

-(+ 2NaOH)
-ONa gets added on the end of the 1st product
-NH becomes comes Nh2
-OH becomes ONa
+h2O

Question 19

What does an amide look like?

Answer 19

-Amides are derived from carboxylic acids.
-In an amide the −OH part of the carboxyl group is replaced by an −NH2 group.

Question 20

What is the gen form for amides?

Answer 20

O
||
RCHNH2

Question 21

what is a primary amide?

Answer 21

n/amine group attached to one m carbon (1 R group)

Question 22

What is a secondary amide?

Answer 22

n/amine group attached to two carbons (2 R groups)

Question 23

What is a tertiary amide?

Answer 23

n/amine group attached to three carbons (3 R groups)

Question 24

when do optical isomers exist?

Answer 24

when there is a chiral carbon atom; one with four different groups/atoms attached to it: the carbon atom is said to be asymmetrically substituted.

Question 25

What does the chiral carbon atom in the molecule mean?

Answer 25

-that there are two non superimposable mirror image structures possible
-These are optical isomers of each other
(often known as enantiomers).

Question 26

What are Diastereoisomers?

Answer 26

compounds with two chiral centres.

Question 27

What are the reactions of amino acids?

Answer 27

amine group with acids
carboxyl group with bases
…..