You are studying a new strain of E. coli that can utilize the disaccharide melibiose very efficiently. You find that utilization depends on the enzyme melibiase, which is encoded by the gene Mel1. Mel1 is not expressed unless melibiose is present in the growth medium.

You next construct a MelA– MelB– double mutant, which gives the following behavior:

 

Which of your two models is consistent with this new data?

a) the MelA- MelB- double mutant is identical to the MelB- mutant

b) MelA- is epistatic to MelB-

c) MelB- is epistatic to MelA-

d) the MelA- MelB- double mutant is identical to the MelA- mutant

Which of the following is the correct prediction about the double mutants?

TLS Online TPP Program

#Question id: 12183

#Unit 1. Molecules and their Interaction Relevant to Biology

Following statements are regarding to regulation of S phase and mitotic cyclin levels in budding yeast.

A. In late anaphase, the anaphase-promoting complex (APC/C) ubiquitinylates S phase and mitotic cyclins.

B. In late anaphase, the anaphase-promoting complex (APC/C) phosphorylates S phase and mitotic cyclins.

C. During exit from mitosis and G1, Cdh1 is dephosphorylated and active; during S phase and mitosis, Cdh1 is phosphorylated and dissociates from APC/C, and APC/C becomes inactive.

D. During exit from mitosis and G1, Cdh1 is phosphorylated and active; during S phase and mitosis, Cdh1 is dephosphorylated and dissociates from APC/C, and APC/C becomes inactive.

E. The G1/S phase CDKs, which themselves are not APC/CCdh1 substrates, phosphorylate Cdh1 at the G1–S phase transition.

F. The G1/S phase CDKs, which themselves are not APC/CCdh1 substrates, ubiquitinylates Cdh1 at the G1–S phase transition.

Which of the following combination is correct?

TLS Online TPP Program

#Question id: 28151

#Unit 1. Molecules and their Interaction Relevant to Biology

Technique based on atomic properties is NMR, NMR Provides Information on an

TLS Online TPP Program

#Question id: 28152

#Unit 1. Molecules and their Interaction Relevant to Biology

Q. NMR signals arise from some properties of atomic nuclei, which are

A. Magnetic moment

B. Angular momentum of the nuclear spin

C. Electronic range

D. Resistivity

Which of the following is true 

TLS Online TPP Program

#Question id: 28153

#Unit 1. Molecules and their Interaction Relevant to Biology

Nuclei that contain an even numbers of protons and an even number of neutrons have I=0 and are known as

TLS Online TPP Program

#Question id: 28154

#Unit 1. Molecules and their Interaction Relevant to Biology

Q. Isotope, Natural Abundance, and  spin (I) are given, and some statement are made

a. 12C=98.9%=NMR-active

b. 16O=99.9%=NMR-active

c. 12C=98.9%=NMR-inactive

d. 16O=98.9%=NMR-inactive

Which of the following is true

TLS Online TPP Program

#Question id: 28155

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following has smallest Bond length in Ang.