Chapter 2: 2.1 Amino acids

Question 1

1. How many amino acids are there?
2. What is the basic structure of an amino acid?

Answer 1

1. 20 amino acids
2. Hydrogen, Carboxylic Acid Group, Amino Group, Side Chain (R group)

Question 2

What are the ways that each amino acid can be named?

Answer 2

1. The full name
2. A three letter identifier
3. A single letter identifier

Question 3

– amino acids can be acquired through diet

Answer 3

10

Question 4

List:

The 10 amino acids can be acquired through diet

Answer 4

1. Phenylalanine (F)
2. Histidine (H)
3. Isoleucine (I)
4. Lysine (K)
5. Leucine (L)
6. Methionine (M)
7. Arginine (R)
8. Threonine (T)
9. Valine (V)
10. Tryptophan (W)

Question 5

Amino acid composition drastically impacts…

Answer 5

1. Protein function
2. Protein characteristics

Question 6

Define:

Site directed mutagenesis

Answer 6

Key amino acids are replaced with other amino acids

Question 7

What can site directed mutagenesis lead to?

Answer 7

• Eliminate protein function
• Alter structure
• Protein unfolding

Question 8

What 3 key amino acids? Describe their side chain structure

Answer 8

1. Alanine: Single methyl group side chain
2. Proline: Side chain forms a ring connected to teh amino group of the backbone
3. Tryptophan: Aromatic side chain

Question 9

Describe:

The behaviour/function of Alanine

Answer 9

Used to virtually delete amino acids during site directed mutagenesis

Question 10

Describe:

The behaviour/function of Proline

Answer 10

Much more rigid than other amion acids
* Often found in turns and the beginning of alpha helices in proteins

Question 11

Describe:

The behaviour/function of Tryptophan

Answer 11

Is fluorescent and absorbs UV light (280 nm), allowing proteins to be monitored

Question 12

Amino acids are Zwitterions.
Define Zwitterions

Answer 12

Molecules with functional groups containing both a positive and a negative charge, resulting in a net neutral charge

Question 13

Define:

pKa

Answer 13

The pH value at which a charged functional group is half protonated and half unprotonated

Question 14

State:

The pKa value of:
1. Carboxylic acid group
2. Amino group

Answer 14

1. ~2
2. ~10

Question 15

If pH < pKa…

Answer 15

Protonated form is predominant

Question 16

If pH > pKa…

Answer 16

Deprotonated form is predominant

Question 17

State the pKa values of the following side chain:

Arginine

Answer 17

12.5

Question 18

State the pKa values of the following side chain:

Lysine

Answer 18

10.5

Question 19

State the pKa values of the following side chain:

Cysteine

Answer 19

8.3

Question 20

State the pKa values of the following side chain:

Histidine

Answer 20

6.0

Question 21

State the pKa values of the following side chain:

Glutamic Acid

Answer 21

4.3

Question 22

State the pKa values of the following side chain:

Aspartic Acid

Answer 22

3.9

Question 23

State the pKa values of the following side chain:

Serine

Answer 23

13.5

Question 24

State the pKa values of the following side chain:

Threonine

Answer 24

13.5

Question 25

# State the pKa values of the following side chain: Tyrosine

Answer 25

10.5