Phosphorylation of a critical threonine residue in the activation loop, Thr-160, allowing substrates to access the active site of the CDK

TLS Online TPP Program

#Id: 8132

#Section 2: General Biology

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: 8131

#Section 2: General Biology

In most mammalian tissues, ubiquinone (also called coenzyme Q) has 10 isoprene units.

Dolichols of animals have 17 to 21 isoprene units (85 to 105 carbon atoms), bacterial dolichols have 11, and those of plants and fungi have 14 to 24.

TLS Online TPP Program

#Id: 8130

#Section 2: General Biology

TLS Online TPP Program

#Id: 8129

#Section 2: General Biology

Some other biologically active isoprenoid compounds or derivatives.

TLS Online TPP Program

#Id: 8127

#Section 2: General Biology

β-Carotene is the precursor of vitamin A1.
Oxidation at C-15 converts retinol to the aldehyde, retinal, and further oxidation produces retinoic acid, a hormone that regulates gene expression. 

TLS Online TPP Program

#Id: 8126

#Section 2: General Biology