As well as synthesizing the transcript, RNA polymerase performs two proofreading functions on that growing transcript;

i. Pyrophosphorolytic editing

ii. Hydrolytic editing

Choose correct processes accordingly,

A. The polymerase backtracks by one or more nucleotides and cleaves the RNA product, removing the error-containing sequence.

B. In this, the enzyme uses its active site, in a simple back-reaction,

C. Catalyze the removal of an incorrectly inserted ribonucleotide, by reincorporation of PPi

D. The enzyme can then incorporate another ribonucleotide in its place in the growing RNA chain.

TLS Online TPP Program

#Question id: 33357

#Unit 1. Structure and Function of Biomolecules

Protein A has a binding site for ligand X with a Kd of 10^-6 µM. Protein B has a binding site for ligand X with a Kd of 10^-9 µM. Which statement is incorrect?

TLS Online TPP Program

#Question id: 33358

#Unit 1. Structure and Function of Biomolecules

Which of the following situations would produce a Hill plot with n<  1.0?

(a) The protein has multiple subunits, each with a single ligand-binding site. Binding of ligand to one site decreases the binding affinity of other sites for the ligand.

(b) The protein is a single polypeptide with two ligand-binding sites, each having a different affinity for the ligand.

(c) The protein is a single polypeptide with a single ligand-binding site.

TLS Online TPP Program

#Question id: 33359

#Unit 1. Structure and Function of Biomolecules

The protein calcineurin binds to the protein calmodulin with an association rate of 8.9 X10³ M^-1s^-1 and an overall dissociation constant, Kd, of 10 nM. The dissociation rate, kd

TLS Online TPP Program

#Question id: 33360

#Unit 1. Structure and Function of Biomolecules

a. HbS (sickle-cell Hb): substitutes a Val for a Glu on the surface

b. Hb Cowtown: eliminates an ion pair involved in T-state stabilization

c. Hb Memphis: substitutes one uncharged polar residue for another of similar size on the surface

d. Hb Bibba: substitutes a Pro for a Leu involved in an α helix

Which Hb variant least likely to cause pathological symptoms

TLS Online TPP Program

#Question id: 33361

#Unit 1. Structure and Function of Biomolecules

a. Hb Cowtown: eliminates an ion pair involved in T-state stabilization

b. Hb Milwaukee: substitutes a Glu for a Val

c. Hb Providence: substitutes an Asn for a Lys that normally projects into the central cavity of the tetramer

d. Hb Philly: substitutes a Phe for a Tyr,

Which Hb variant will not bind to BPG

TLS Online TPP Program

#Question id: 33362

#Unit 1. Structure and Function of Biomolecules

a. Hb Cowtown: eliminates an ion pair involved in T-state stabilization

b. Hb Milwaukee: substitutes a Glu for a Val

c. Hb Providence: substitutes an Asn for a Lys that normally projects into the central cavity of the tetramer

d. Hb Philly: substitutes a Phe for a Tyr

Which Hb variant will have changed pI as compared to HbA