Questions and Answers

A 5250 base-pair long plasmid with 10 negative supercoils would have a linking number of __________, considering 10.5 base pairs per turn for B DNA.

In Michaelis-Menten’s equation, if [S]=15Km[S] = 15 K_m[S]=15Km​, then the ratio v0Vmax\frac{v_0}{V_{max}}Vmax​v0​​ is __________.

Factor H, a complement regulatory protein in plasma, binds C3b and

(A) competes with factor B to displace Bb from convertase.
(B) initiates the catabolism of C3b into inactive products.
(C) then binds to C3bBb convertase.
(D) acts as a cofactor for factor I.

Which one or more of the following statements correctly describe(s) the changes upon the addition of puromycin during eukaryotic translation?

(A) Puromycin resembles the aminoacyl end of the charged tRNA.
(B) Puromycin occupies the A site of the translating ribosomes.
(C) Puromycin occupies the P site of the translating ribosomes.
(D) Puromycin occupies the E site of the translating ribosomes.

Which one or more of the following statements is/are correct in the processing of pre-mRNA in eukaryotes?

(A) 3′ → 5′ exonuclease activity is involved in the conversion of pre-mRNA to mRNA.
(B) 5′-capping and addition of 3′-poly A tail precede splicing.
(C) Splicing of pre-mRNA occurs via transesterification reaction.
(D) Alternative splicing can yield different mRNA products from the same pre-mRNA.

Which one or more of the following statements correctly describe(s) fluorescence spectroscopy?

(A) The emission maxima (λmax) is independent of the excitation wavelength.
(B) The emission maxima (λmax) depends on the concentration of a quencher.
(C) The emission maxima (λmax) varies with solvent polarity.
(D) The emission maxima (λmax) varies with temperature.