A cell does not want to waste energy synthesizing the amino acid arginine if arginine is present in its diet. Therefore, when arginine is present, it activates a repressor protein to prevent transcription of genes that code for enzyme to make arginine. This is an example of what type of regulation?

TLS Online TPP Program

#Question id: 12018

#Unit 10. Ecological Principles

The amount of energy entering a food chain depends on the

TLS Online TPP Program

#Question id: 12019

#Unit 10. Ecological Principles

Chickadees were given an opportunity to store seeds in 72 possible storage sites consisting of holes drilled in small trees that had been placed in an aviary. Typically, the seeds were placed in only 4 or 5 storage sites. The chickadees were then removed from the aviary, the seeds removed from the storage sites, and each hole covered. A day later, the chickadees were returned to the aviary and they spent nearly 5 times as long pulling at the covers on storage sites than at the covers on sites where they had not stored food. This experiment indicates that chickadees

TLS Online TPP Program

#Question id: 12020

#Unit 10. Ecological Principles

Bird species X stores seeds in a large number of separate caches in the summer and then locates the caches in the winter. Compared with a bird species that does not store seeds, species X can be expected to have a proportionately larger

TLS Online TPP Program

#Question id: 12021

#Unit 7. System Physiology – Animal

Nutrient-rich blood from the intestine is carried through the ________ to the liver.

TLS Online TPP Program

#Question id: 12022

#Unit 7. System Physiology – Animal

The bile salts ________.

TLS Online TPP Program

#Question id: 12023

#Unit 7. System Physiology – Animal

The absorption of fats differs from that of carbohydrates in that ________.