Marine turtles and seabirds ingest seawater when consuming prey or drink it, having no access to fresh water.

These animals have specialized structures called salt glands located around the eyes and nostrils.

TLS Online TPP Program

#Id: 10116

#Unit 6. System Physiology – Plant

IAA is synthesises by tryptophan and is primarily synthesized in a two-step process 

Indole-3-pyruvate (IPyA) as the intermediate. 

The second step in the pathway is carried out by the YUCCA gene product, a tryptophan aminotransferase.

TLS Online TPP Program

#Id: 10117

#Unit 6. System Physiology – Plant

Auxins in biological samples can be determined by bioassay, mass spectrometry, or enzyme-linked immunosorbent assay (ELISA).

The Avena coleoptile curvature assay is a sensitive measure of auxin activity (it is effective for IAA concentrations of about 0.02 to 0.2 mg L–1).

TLS Online TPP Program

#Id: 10118

#Unit 6. System Physiology – Plant

Trp transaminase

Tryptophan (Trp)-----------------------→ Indole-3-pyruvic acid

IPA decarboxylase

(IPA) -----------------------→ Indole-3-acetaldehyde (IAld)

---------------------------------------→ Indole-3-acetic acid (IAA)

TLS Online TPP Program

#Id: 10119

#Unit 6. System Physiology – Plant

In plants that produce indole glucosinolate defense compounds, IAA can also be synthesized from tryptophan via a pathway with indole acetonitrile as an intermediate

TLS Online TPP Program

#Id: 10120

#Unit 6. System Physiology – Plant

In maize kernels, IAA also appears to be synthesized by a tryptophan independent pathway via indole-3- glycerol phosphate

TLS Online TPP Program

#Id: 10121

#Unit 6. System Physiology – Plant

Covalent conjugation of amino acids to IAA can also result in permanent inactivation.