According to Optimal Defense Hypothesis, 

Young tissues not only contain the highest levels of constitutive secondary compounds, they are also more responsive to herbivory. Thus, younger leaves exhibit more robust inducible defenses to herbivores than older leaves.

TLS Online TPP Program

#Id: 8035

#XL - Q Biochemistry

Negatively charged amino acids have four ionisations zones

1. 1--------pK1 – charge +1

2. pK1---------pKr charge 0

3. pKr---------pK2 charge -1

4. pK2---------14 charge -2

TLS Online TPP Program

#Id: 8034

#XL - Q Biochemistry

Nonpolar amino acids have three ionisations zones

1. 1--------pK1 – charge +1

2. pK1---------pK2 charge 0

3. pK2---------14 charge -1

TLS Online TPP Program

#Id: 8033

#XL - Q Biochemistry

Glycine & Proline are relatively polar considering negative hydropathy index (-0.4 & -1.6) comparing to other nonpolar amino acids.

TLS Online TPP Program

#Id: 8032

#XL - Q Biochemistry

Ornithine and citrulline, which are not found in proteins, are intermediates in the biosynthesis of arginine and in the urea cycle.

TLS Online TPP Program

#Id: 8031

#XL - Q Biochemistry

TLS Online TPP Program

#Id: 8030

#XL - Q Biochemistry

Desmosine is formed from four Lys residues