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TLS Online TPP Program

#Question id: 720

How would a homopolymer of alanine be more likely to form an alpha helix in water or in a hydrophobic medium?

#Unit 1. Molecules and their Interaction Relevant to Biology

  1. In an aqueous environment, the formation of intrachain hydrogen bonds stabilizes the amide hydrogen atoms and carbonyl oxygen atoms of the polypeptide chain, and so an alpha helix forms. In an hydrophobic environment, these groups are stabilized by interaction with water, and so there is no energetic reason to form an a helix. Thus, the alpha helix would be more likely to form in a aqueous environment.

  2. In a hydrophobic environment, the formation of intrachain hydrogen bonds stabilizes the amide hydrogen atoms and carbonyl oxygen atoms of the polypeptide chain, and so an alpha helix forms. In an aqueous environment, these groups are stabilized by interaction with water, and so there is no energetic reason to form an alpha helix. Thus, the alpha helix would be more likely to form in a hydrophobic environment.

  3. In both hydrophobic environment as well as aqueous environment, the formation of intrachain hydrogen bonds stabilizes the amide hydrogen atoms and carbonyl oxygen atoms of the polypeptide chain, and so an alpha helix forms.

  4. In a aqueous environment, the formation of interchain hydrogen bonds stabilizes the amide hydrogen atoms and carbonyl oxygen atoms of the polypeptide chain, and so an alpha helix forms. In an hydrophobic environment, these groups are stabilized by interaction with water, and so there is no energetic reason to form an alpha helix. Thus, the alpha helix would be more likely to form in a aqueous environment.

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TLS Online TPP Program

#Question id: 642

#Unit 1. Molecules and their Interaction Relevant to Biology

The graphs P, Q and R show the variation of rate constant (k) with temperature. The reactions represented by P, Q and R, respectively, are
TLS Online TPP Program

#Question id: 641

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following does NOT describe a mechanism that cells use to regulate enzyme activities?

A. Cells control enzyme activity by phosphorylation and dephosphorylation.

B. Cells control enzyme activity by the binding of small molecules.

C. Cells control the rates of diffusion of substrates to enzymes.

D. Cells control the rates of enzyme degradation.

E. Cells control the rates of enzyme synthesis.

F. Cells control the targeting of enzymes to specific organelles. 
TLS Online TPP Program

#Question id: 640

#Unit 1. Molecules and their Interaction Relevant to Biology

The data in the table above were collected for an enzyme-catalyzed reaction. The Km for this enzyme is approximately
TLS Online TPP Program

#Question id: 639

#Unit 1. Molecules and their Interaction Relevant to Biology

Match the coenzymes in column I enzymes to class of enzymes in column II

EnzymeReaction Type
A. Phosphofructokinase1. Redox reaction
B. Enolase2. Phosphoryl shift
C. Phosphoglycerate mutase3. Dehydration
D. Glyceraldehyde 3 Phosphate dehydrogenase4. Phosphoryl transfer
TLS Online TPP Program

#Question id: 638

#Unit 1. Molecules and their Interaction Relevant to Biology

Match the following class of enzymes with them

EnzymeClass of enzyme
A. Hexokinase1
B. Phosphoglucoisomerase2
C. Glyceraldehyde 3-phosphate dehydrogenase3
D. Phosphoglycerate mutase4
E. Enolase5
F. Aldolase
TLS Online TPP Program

#Question id: 637

#Unit 1. Molecules and their Interaction Relevant to Biology

Effect of temperature on enzymatic catalysis is analysed by the rate v of a chemical reaction varies with temperature according to the Arrhenius Equation which explains the sensitivity of enzyme reactions to temperature. A plot to determination of the activation energy Ea involves