#Question id: 5327
#Unit 8. Inheritance Biology
In the human pedigree shown here, the daughter indicated by the black circle (II-1) has a form of deafness determined by a recessive allele. What is the probability that the phenotypically normal son (II 3) is heterozygous for the gene?
#Question id: 909
#Unit 1. Molecules and their Interaction Relevant to Biology
Most proteins denature at both high and low pH. At high pH, the ionization of internal tyrosines is thought to be the main destabilizing influence, whereas at low pH, the protonation of buried histidines. A titration curve for the unfolding of the enzyme ribonuclease is shown in Figure. Given the relation between the titration curves for protein unfolding and histidine protonation, which of the following conclusion can be drawn correctly?
A. The sharp transition in graph indicates a highly cooperative process; when the protein starts to unfold, it completes the process rapidly
B. The sharp transition in graph indicates a highly noncooperative process
C. Several buried histidines can ionize when the chain starts to unfold, so that when one goes, they all go together due to cooperative behaviour of protein folding
D. Buried histidine (pK of 4 in this example) becomes accessible to solvent, its pK will shift toward its normal value of 6, significantly steepening its titration curve.
#Question id: 4569
#Unit 11. Evolution and Behavior
Which of the following must exist in a population before natural selection can act upon that population?
#Question id: 585
#Unit 1. Molecules and their Interaction Relevant to Biology
In an enzyme reaction involving one enzyme and one substrate, the rate of the reaction depends on
#Question id: 7290
#Unit 5. Developmental Biology
Following figure regarding to regulatory network in the Arabidopsis shoot meristem stem-cell niche.
A. The transcription factor WUS is synthesized in the cell A and moves via plasmodesmata into cell B, where one of its functions is to induce expression of the CLV3.
B. The transcription factor CLV3 is synthesized in the cell A and moves via plasmodesmata into cell B, where one of its functions is to induce expression of the WUS.
C. Secreted CLV3 protein from cell B binds to the receptor protein kinase on the surface of cell A; there, it activates a signal that represses WUS transcription.
D. Secreted WUS protein from cell B binds to the receptor protein kinase on the surface of cell A; there, it activates a signal that represses CLV3 transcription.
Which of the following combination is correct?