If relatively small carbonaceous chondrites from space were a significant source of Earthʹs original amino acids, then which two of these would have been most important in permitting their organic materials to survive impact with Earth?

I. Carbonaceous chondrites must contain no D-amino acids.

II. Earthʹs early atmosphere must have had little free oxygen.

III. The chondrites must have arrived on Earth before 4.2 billion years ago.

IV. Earthʹs early atmosphere must have been dense enough to dramatically slow the chondrites before they impacted.

V. The chondrites must have impacted land, rather than a large body of water.

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#Question id: 12636

#Unit 6. System Physiology – Plant

Which of the following is the correct prediction about Strigolactones?

TLS Online TPP Program

#Question id: 12637

#Unit 6. System Physiology – Plant

Strigolactones are synthesized from β-carotene , in which 9-cis-β-Carotene is coverted into the 9-cis-β-apo-10‘-carotenal by sequential cleavage  in the plastids by enzyme known as,

TLS Online TPP Program

#Question id: 12638

#Unit 6. System Physiology – Plant

strigolactone biosynthesis takes place , find the correct sequence of these signal transduction pathways;

a) D14* hydrolyses strigolactone and releases the products of hydrolysis. 

b) D14 disengages from the SCFMAX2 complex and returns to its original conformation, allowing it to respond to fresh strigolactone signal.

c) D14* interacts with the F-box protein MAX2 and the other partners of the SCFMAX2 ubiquitin ligase complex.

d) The α-/β-fold hydrolase D14 binds and reacts with strigolactone, changing its conformation to the active form, D14*

e) Target protein(s) are recognized by the D14*–SCFMAX2 complex and are ubiquitinated

TLS Online TPP Program

#Question id: 12639

#Unit 6. System Physiology – Plant

Strigolactones are transported out of sites of synthesis via plasma membrane and have been shown to move in the xylem from root to shoot by which transporter?

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#Question id: 12640

#Unit 6. System Physiology – Plant

Plant species produce a which type of  defensive proteins that bind to carbohydrates or carbohydrate-containing proteins. After being ingested by an herbivore, that bind to the epithelial cells lining the digestive tract and interfere with nutrient absorption

TLS Online TPP Program

#Question id: 12640

#Unit 10. Ecological Principles

Plant species produce a which type of  defensive proteins that bind to carbohydrates or carbohydrate-containing proteins. After being ingested by an herbivore, that bind to the epithelial cells lining the digestive tract and interfere with nutrient absorption