#Question id: 5648
#Unit 5. Developmental Biology
Use the following information to answer the question. In order to test how sea urchin sperm bind to eggs, scientists isolated the egg receptor protein that binds to the sperm acrosomal protein called bindin. Plastic beads were coated with egg receptor for bindin (ERB1) from eggs of the sea urchin Strongylocentrotus purpuratus, and then the beads mixed with sperm from S. purpuratus or from the related species, S. franciscanus. The researchers counted how many sperm were bound to each bead. The results are shown in the graph below. Treatments:
A: S. purpuratus sperm mixed with S. purpuratus ERB1 beads
B: S. purpuratus sperm mixed with beads containing no ERB1 protein
C: S. franciscanus sperm mixed with S. purpuratus ERB1 beads
D: S. franciscanus sperm mixed with beads containing no ERB1 protein
What is a broader implication from the observations of the experiment?
#Question id: 10506
#Unit 6. System Physiology – Plant
Plant growth promoting rhizobacteria (PGPRs) such as Pseudomonas aeruginosa, that alleviate plant abiotic or biotic stress in soil by releasing of
#Question id: 4715
#Unit 11. Evolution and Behavior
Claytonia virginica is a woodland spring herb with flowers that vary from white, to pale pink, to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so that Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time?
#Question id: 3878
#Unit 3. Fundamental Processes
Which of the following statements about the synthesis of rRNA and tRNA in E. coli is true?
#Question id: 10383
#Unit 6. System Physiology – Plant
The nitrogenase enzyme complex fixes N2 produces ammonia, The nitrogenase
enzyme complex catalyzes this reaction by following characteristics given
below;
a) It can be separated into two components—the Fe protein and the MoFe
protein— neither of which has catalytic activity by itself
b) Fe protein is the smaller of the two components and has two identical
subunits, each contains an iron–sulfur cluster, which participates in the redox
reactions
c) The Fe protein is irreversibly inactivated by O2 while MoFe protein is
activated by O2
d) MoFe protein has four subunits, each subunit has two Mo–Fe–S clusters
e) Ferredoxin serves as an electron donor to the Fe protein, and Fe
protein reduces the MoFe protein without any hydrolysing ATP
f) Only prokaryotes have nitrogenase enzyme
Which of the following characteristics of nitrogenase enzyme complex is incorrect?