#Question id: 221
#Unit 1. Molecules and their Interaction Relevant to Biology
Which statement is false about 5,6,7,8-tetrahydrobiopterin?
#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: 4220
#Unit 3. Fundamental Processes
A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed?
#Question id: 31151
#Unit 2. Cellular Organization
#Question id: 5668
#Unit 5. Developmental Biology
Following statements are made in relation to the five widely recognized stages of Arabidopsis embryogenesis:
A. The fusion of haploid egg and sperm takes place in zygotic stage
B. Rapid cell division in two regions on either side of the future shoot apex forms globular stage
C. The cell elongation throughout the embryo axis and further development result in Torpedo stage
D. The embryo loses water and becomes metabolically inactive in the torpedo stage
Which combination of the above statements is correct?