Unit 4 Amino acids Flashcards Preview

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Flashcards in Unit 4 Amino acids Deck (11)
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0
Q

What happens when an amino acid is placed in acidic conditions?

A

The NH2 group accepts a proton to become NH3+

1
Q

Why do amino acids have relatively high melting points?

A

As they exist as zwitter ions there are strong electrostatic forces of attraction between molecules meaning more energy is needed to melt them

2
Q

What happens when an amino acid is placed in alkaline conditions?

A

The carboxylic acid group becomes deprotonated to become COO-

3
Q

What type of bond joins consecutive amino acids within proteins?

A

Amide bonds - sometimes referred to as peptide links

4
Q

How are proteins split back into their constituent amino acids?

A

They are hydrolysed by heating with dilute acid

5
Q

What is a molecule made up of two amino acids called?

A

Dipeptide

6
Q

Do amino acids show optical activity?

A

All amino acids, except glycine, show optical activity as the central carbon is chiral as there are 4 different groups attached to it

7
Q

What is the IUPAC name for lycine - NH2CH(COOH)(CH2)4NH2

A

2,6-diaminohexanoic acid

8
Q

How can amino acids be separated?

A

Chromatography

9
Q

Why do different amino acids have different retention times?

A

Each amino acid will interact differently with the stationary phase. The stronger the interactions, the higher the retention time

10
Q

Proteins chains are often arranged in the shape of a helix (spiral). What type of bonding is responsible for this and between which elements do these bonds occur?

A

Hydrogen bonds form between the H of the N-H and the O of the C=O