#Question id: 1275
#Unit 4. Cell Communication and Cell Signaling
The functions of the extracellular matrix include:
a. supporting differentiation.
b. inducing morphogenesis.
c. binding growth hormones.
d. repairing damaged tissue
which of the following combination is correct?
#Question id: 11644
#Unit 7. System Physiology – Animal
Seven days after ovulation, pituitary secretion of luteinizing hormone (LH) decreases rapidly. What is the cause of this decrease in secretion?
#Question id: 4108
#Unit 3. Fundamental Processes
The yeast Gal4 transcription activator comprises two domains: a DNA binding domain and an activation domain. The DNA-binding domain allows Gal4 to bind to appropriate DNA sequences located near genes that are required for metabolism of the sugar galactose. The activation domain binds to components of the transcriptional machinery (including RNA polymerase), attracting them to the promoter, so the regulated genes can be turned on. In the absence of Gal4, the galactose genes cannot be turned on. When Gal4 is expressed normally, the genes can be maximally activated. When Gal4 is massively overexpressed, however, the galactose genes are turned off. Choose correct explanation for this regulation?
A. In order for Gal4 to work properly, the DNA-bound Gal4 recruits many proteins, including RNA polymerase, to the promoter.
B. When there is too much Gal4 in the cell, the free and DNA-bound Gal4 will compete for the limited quantities of these other components.
C. In the presence of excess Gal4, those components are tied up in unproductive complexes with free Gal4, thereby preventing their recruitment to the promoter.
D. cells that massively overexpress Gal4 grow poorly because of the reduced availability of critical components of the transcription machinery.
E. Over concentration of Gal4 prevent suppressors to bind with DNA
#Question id: 27485
#Unit 1. Molecules and their Interaction Relevant to Biology
Two sugars that differ in configuration at only one chiral center are described as
#Question id: 23201
#Unit 13. Methods in Biology