Lipids as pigments in plants and bird feathers.

Birds acquire the pigments that color their feathers red or yellow by eating plant materials that contain carotenoid pigments, such as canthaxanthin and zeaxanthin.

The differences in pigmentation between male and female birds are the result of differences in intestinal uptake and processing of carotenoids.

TLS Online TPP Program

#Id: 8132

#XL - Q Biochemistry

Lipids as pigments in plants and bird feathers.

Birds acquire the pigments that color their feathers red or yellow by eating plant materials that contain carotenoid pigments, such as canthaxanthin and zeaxanthin.

The differences in pigmentation between male and female birds are the result of differences in intestinal uptake and processing of carotenoids.

TLS Online TPP Program

#Id: 8132

#XL - T Zoology

Lipids as pigments in plants and bird feathers.

Birds acquire the pigments that color their feathers red or yellow by eating plant materials that contain carotenoid pigments, such as canthaxanthin and zeaxanthin.

The differences in pigmentation between male and female birds are the result of differences in intestinal uptake and processing of carotenoids.

TLS Online TPP Program

#Id: 9469

#XL - T Zoology

IL-2 receptor complex activates

STATs 1, 3, and 5 but not STATs 2 or 4

TLS Online TPP Program

#Id: 9470

#XL - T Zoology

Phosphorylated STAT dissociates spontaneously from the receptor, and two phosphorylated STAT proteins form a homodimer.

TLS Online TPP Program

#Id: 9471

#XL - T Zoology

STAT5 becomes activated in erythroid progenitor cells and induces expression of the protein Bcl-xL.

TLS Online TPP Program

#Id: 9472

#XL - T Zoology

Two mechanisms for terminating cytokine signaling:

1. Short-term regulation: SHP1

2. Long-term regulation: SOCS proteins

TLS Online TPP Program

#Id: 9473

#XL - T Zoology

SHP1 a phosphotyrosine phosphatase, contains:

SH2 domain  & Phosphatase domain

TLS Online TPP Program

#Id: 9474

#XL - T Zoology

SHP1 

Binding of an SH2 domain to a phosphotyrosine in the activated receptor unmasks its phosphatase catalytic site