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TLS Online TPP Program

#Question id: 20324

What is the main difference between Gram positive and Gram-negative quorum sensing mechanism?

#Unit 4. Cell Communication and Cell Signaling
  1. Gram-negative bacteria use mainly peptides while Gram-positive bacteria use predominantly N-acyl homoserine lacton (AHL) molecules 
  2. Gram-negative bacteria use predominantly N-acyl homoserine lacton (AHL) molecules while Gram-positive bacteria use mainly peptides.
  3. Gram-negative bacteria use mainly peptides while Gram-positive bacteria use predominantly autoinducer-1, AI-1.
  4. Gram-positive bacteria is more resistance to antibiotics than Gram- negative.
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TLS Online TPP Program

#Question id: 12998

#Unit 1. Molecules and their Interaction Relevant to Biology

Match with appropriate bonding pattern
TLS Online TPP Program

#Question id: 12997

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the given reason is correct to minimize the repulsion in an α-helix
a) positively charged amino acids are often found near the amino terminus of the helical segment
b) negatively charged amino acids are often found near the amino terminus of the helical segment
c) positively charged amino acids are often found near the C-terminus of the helical segment.
d) negatively charged amino acids are often found near the C-terminus of the helical segment.
TLS Online TPP Program

#Question id: 12996

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following is incorrect regarding to α-helix
a) In the α helix, the first four NH groups and last four CO groups will normally lack backbone  hydrogen bonds.
b) the length of an amino acid in α-helix reduced almost 3 times than linear structure.
c) the frequent occurrence of Pro and Gly residues favour α-helix formation.
d) dihedral (ϕ and ψ) angle should be close to -57 and -47.
TLS Online TPP Program

#Question id: 12995

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following constraints affect the stability α-helix, 
a) the intrinsic propensity of an amino acid residue to form an α-helix.
b) the interactions between R groups.
c) the bulkiness of adjacent R groups.
d) the occurrence of Pro and Gly residues.
TLS Online TPP Program

#Question id: 12994

#Unit 1. Molecules and their Interaction Relevant to Biology

α-helix changes their configurations according to the environment then
a. when found in aqueous or plasm environment 
b. when found in membrane or hydrophobic environment
in the given condition interaction will be 
TLS Online TPP Program

#Question id: 12993

#Unit 1. Molecules and their Interaction Relevant to Biology

Out of these which of the following is true regarding the propensity of α-helix.
a. any amino acid which can take up desirable ϕ and ψ angle close to -57 and -47 will favour the formation of a α-helix
b. amino acid such a proline and glycine have lowest propensity will favour formation of α-helix.
c. if the resultant change in the value ΔΔG0 is positive then it will favour the formation of α-helix.
d. if the resultant change in the value ΔΔG0 is zero or close to zero then it will favour the formation of α-helix.