Precision will be reduced, but yield will be increased

Optimisation of a PCR reaction is often a compromise between the competing demands for precision, efficiency and yield. Although the specific effects may vary, generally, increasing the annealing temperature will increase non-specific primer binding and reduce precision. Increasing the length of the elongation phase will reduce the proportion of incomplete newly-synthesised strands and therefore increase yield. In this case, the potential effect on efficiency is unclear. Increasing the elongation phase would increase the reaction time, but the time taken to ramp down to a lower annealing temperature would be reduced.

In blue white screening insertional activation of Beta-D-galactosidase will give rise to

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#Question id: 12991

#Section 2: General Biology

Choose the correct statements

a. Secondary structures are stabilized by hydrogen bonds.

b. Hydrogen bond always formed between non bonded atoms.

c. the folded length of an amino acid in α-helix reduced almost 3 times than linear structure.

d. Only dihedral angle changes during the formation of secondary structure while bond length remains unchanged

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#Question id: 12992

#Section 2: General Biology

α-helix changes its configurations according to the environment then

a. membrane encompassing α-helix have nonpolar residue oriented toward the membrane lipid.

b. if α-helix is found in plasm then polar residue will be oriented toward the outside.

c. if α-helix is found in plasm then nonpolar residue will be present inside the core.

d.  membrane encompassing α-helix have polar residue oriented towards the membrane lipid.

Choose incorrect statement

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#Question id: 12993

#Section 2: General 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.

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#Question id: 12995

#Section 2: General 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.

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#Question id: 12996

#Section 2: General 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.

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#Question id: 12997

#Section 2: General 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.