#Question id: 9584
#Unit 6. System Physiology – Plant
In given Relationship of oxygen production to flash energy, the first evidence for the interaction between the antenna pigments and the reaction centre, What conclusion can be drawn about based on graph;
a.) several hundred pigments are associated with each reaction centre and that each reaction centre must operate four times to produce 1 molecule of oxygen—hence the value of 2500 chlorophylls per O2
b.) low light intensity of the curve, an increase in the number of photons stimulates a proportional increase in oxygen evolution. Thus, the slope of the curve measures the quantum yield for oxygen production
c.) The quantum yield for a particular process can range from 0 →if that process does not respond to light to 1.0→if every photon absorbed contributes to the process by forming a product
d.) O2 require more than a single photochemical event to be formed, and therefore have a lower quantum yield of formation than the photochemical quantum yield. It takes about ten photons to produce one molecule of O2, so the quantum yield of O2 production is about 0.1
Which of the following statements would be correct relates with graph?
#Question id: 2255
#Unit 2. Cellular Organization
Following statements are regarding to the Na+/K+ ATPase maintains the intracellular Na+ and K+ concentrations in animal cells. Which of the following statement is incorrect?
#Question id: 11062
#Unit 7. System Physiology – Animal
The alveolar pressure of a normal 77-year-old woman is approximately 1 cm H2O during expiration. What is the alveolar pressure during inspiration (in cm H2O)?
#Question id: 14699
#Unit 13. Methods in Biology
If A and B are arbitrary events, then
#Question id: 4104
#Unit 3. Fundamental Processes
Consider following statements for catalytic mechanism of RNA polymerase
A. RNA synthesis by RNA polymerase. The reaction involves two Mg2+ ions, coordinated to the phosphate groups of the incoming nucleoside triphosphates (NTPs)
B. Three Asp residues, which are highly conserved in the RNA polymerases of all species. One Mg2+ ion facilitates attack by the 39-hydroxyl group on the phosphate of the NTP; the other Mg2+ ion facilitates displacement of the pyrophosphate, and both metal ions stabilize the pentacovalent transition state.
C. About 17 bp of DNA are unwound at any given time. RNA polymerase and the transcription bubble move from left to right along the DNA as shown, facilitating RNA synthesis. Movement of an RNA polymerase along DNA tends to create negative supercoils (overwound DNA) ahead of the transcription bubble and positive supercoils (underwound DNA) behind it.
D. The RNA polymerase is in close contact with the DNA ahead of the transcription bubble as well as with the separated DNA strands and the RNA within and immediately behind the bubble. A channel in the protein funnels new NTPs to the polymerase active site. The polymerase footprint encompasses about 35 bp of DNA during elongation.