1 - Amino acids

Question 1

What do alpha-amino acids have? What does this result in?

Answer 1

They have a basice amine group and an acidic carboxyl group. This means they’e soluble in both acids and bases.

Question 2

What’s the general formula of Amino acids?

Answer 2

RCH(NH2)COOH.

Question 3

What are the different R groups in amino acids?

Answer 3

-OH, -SH, -COOH, -NH2 - or in the case of Glycine H is the R group.

Question 4

How does a Zwitterion form?

Answer 4

Carboxyl group and basic amine group interact with each other to form a zwitterion. A proton is transferred from the acid caboxyl group to the basic amine group. Therefore there is no overall charge.

Question 5

When do Zwitterionions exist?

Answer 5

Zwitterions of all amino acids exist at the pH valuer for the isoelectric point.

Question 6

What is the Isoelectric Point?

Answer 6

The pH value at which all amino acids exist as zwitterions.

Question 7

Amino acids are amphoteric; what does this mean?

Answer 7

Amphoteric means they can react with acids and bases.

Question 8

What are zwitterions?

Answer 8

Zwitterions are dipolar ionic forms of amino acids that are formed by the donation of Hydrogen ions from the carboxyl group to the amine group - hence why there’s no overall charge.

Question 9

What happens at a pH value more than the isoelectric point?

Answer 9

More than Isoelectric Point: Amino acids act as bases and accept a proton from the acid. The amino acid is a positively charged ion.

Question 10

What happens at a pH value less than the isoelectric point?

Answer 10

Less than Isoelectric Point: Amino acids act as an acid and donate a proton to the base. The amino acid is a negatively charged ion.