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.

Which one or more of the following statements is/are correct regarding the transport and retention of proteins in different cell organelles?

(A) Mannose 6-phosphate residues are involved in targeting proteins to lysosomes.
(B) Transport of proteins into the mitochondrial compartment is aided by positively charged amino acid residues at the N-terminus and internal hydrophobic segments.
(C) The retention of protein in the ER lumen requires the KDEL sequence motif at the C-terminus.
(D) Nuclear proteins are transported in an unfolded conformation and the nuclear localization signal sequence is subsequently cleaved by peptidases in the nucleoplasm.

Which one or more of the following statements is/are correct regarding the electromotive force generated by the electron transfer chain?

(A) It is used for the synthesis of ATP.
(B) It is not used for active transport processes.
(C) It includes a pH gradient component.
(D) It does not include an electrical potential gradient component.