TLS Online TPP Program

#Question id: 718


Poly- L -leucine in an organic solvent such as dioxane is a helical, whereas poly- L isoleucine is not. Why do these amino acids with the same number and kinds of atoms have different helix-forming tendencies?

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. Leucine has bulky side chain than isoleucine so it forms helix.

  2. Methyl group at γ position of isoleucine cause stearic hindrance and blocks helix formation tendency

  3. Due to the stearic hindrance caused by β carbon- methyl group, isoleucine can’t form helix. Methyl group at γ position of isoleucine cause stearic hindrance and blocks helix formation tendency.

  4. Isoleucine has chiral carbon due to which it can,t form poly-L isoleucine helix.

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TLS Online TPP Program

#Question id: 5037

#Unit 5. Developmental Biology

Genes control development by:

TLS Online TPP Program

#Question id: 7286

#Unit 5. Developmental Biology

Which of the floral whorls is affected in apetala 3/pistillata (ap3/pi) mutants?

TLS Online TPP Program

#Question id: 11415

#Unit 10. Ecological Principles

Below is a list of various bird groups, with their typical age at maturity (in years). Which of these would you expect to have the greatest annual survival?

TLS Online TPP Program

#Question id: 10931

#Unit 7. System Physiology – Animal

A 24-year-old African-American man comes to the emergency room 3 hr after the onset of severe back and chest pain. These problems started while he was skiing. He lives in Los Angeles and had a previous episode of these symptoms 5 years ago while visiting Wyoming. He is in obvious pain. Laboratory studies show the following:

Hemoglobin                                        11 gm/dl

Leukocyte count                                 22,000/μl3

Reticulocyte count                              25%

What is the diagnosis of this patient?

TLS Online TPP Program

#Question id: 13195

#Unit 1. Molecules and their Interaction Relevant to Biology

Who contributes to the stability of DNA helix structure?
A. Hydrogen bonding between bases
B. Hydrogen bonding between water and bases
C. Scattering interactions between bases
D. Stacking interactions between bases
CORRECT combination is