The 3D structure of the complete Escherichia coli ribosome with bound mRNA and tRNAs revealed that the very amino terminus of one protein (L27) does reach into the active site. This finding suggested a role for this protein in catalysis. To test this possibility, the nine amino acids at the L27 amino terminus that were in close proximity to the active site were eliminated by mutation. The following possible outcomes were found to be correct as

A. The resulting cells produced ribosomes with reduced but detectable peptidyl transferase activity

B. Region of the L27 protein contributes to peptidyl transferase activity

C. The mutant ribosomes, didn’t synthesised wildtype levels of cells

D. Vast majority of this increase in peptide bond formation is retained, even without the presence of L27 in the active site

E. The most likely role for L27 is to correctly position one or more of the RNA components of the active site

TLS Online TPP Program

#Question id: 11488

#Unit 1. Molecules and their Interaction Relevant to Biology

If approximately 415 kJ/mol of energy is being used to break a bond in a monosaccharide molecule then

A. That monosaccharide is undergoing conformational change

B. That monosaccharide is undergoing configurational change

C. That monosaccharide is undergoing mutarotation to change into other form

D. That monosaccharide is undergoing epimerisation to change into other form

Which of the above statements is/are correct for a molecule to change with an expense of that much of energy?

TLS Online TPP Program

#Question id: 11489

#Unit 1. Molecules and their Interaction Relevant to Biology

Why Trehalose does cannot get oxidized at its anomeric carbon

TLS Online TPP Program

#Question id: 11490

#Unit 2. Cellular Organization

Valinomycin, which is one of the best characterized ionophores, specifically transports

TLS Online TPP Program

#Question id: 11491

#Unit 2. Cellular Organization

What is the “signature sequence” that is highly conserved in all K+ channels?

TLS Online TPP Program

#Question id: 11492

#Unit 2. Cellular Organization

Which of the following integral membrane protein transport chemotherapeutic drug out of the cell and prevents their accumulation within a tumor and thus blocks their therapeutic effects?

TLS Online TPP Program

#Question id: 11493

#Unit 2. Cellular Organization

Which of the following membrane protein form channel, in the form of gap junctions between cells?