#Question id: 11419
#Unit 10. Ecological Principles
There are more species in tropical areas than in places more distant from the equator. This is probably a result of
a) more predators and parasites
b) more dispersed annual solar radiation compared to the poles
c) more frequent ecological disturbances over a longer time span
d) a longer time frame without disturbances for evolution and speciation
#Question id: 994
#Unit 1. Molecules and their Interaction Relevant to Biology
If the 16-carbon saturated fatty acid palmitate is oxidized completely to carbon dioxide and water (via the B-oxidation pathway and the citric acid cycle), and all of the energy-conserving products are used to drive ATP synthesis in the mitochondrion, the net yield of ATP per molecule of palmitate is:
#Question id: 26947
#Unit 10. Ecological Principles
Calculate the finite rate of increase, if ecologists count the number of insects in the population, N0=200, the next year ecologists count 260 insects in the same population?
#Question id: 28597
#Unit 2. Cellular Organization
#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