TLS Online TPP Program

#Question id: 2904


When the temperature of a solution of DNA is raised to near the boiling point of water, the optical density, (called absorbance) at 260 nm markedly increases, a phenomenon known as hyperchromicity. Which of the following properties gets changed due to subsequent denaturation of the DNA molecule?

#Unit 2. Cellular Organization
  1. The solutions of native DNA exhibit high viscosity because of the relatively rigid double helical, long and rod like character of DNA molecule. Denaturation causes a marked decrease in viscosity.

  2. Denaturation of DNA double helix can also be brought about by certain chemical agents such as urea and formamide. These chemical reagents enhance the aqueous solubility of the purine and pyrimidine groups.

  3. Double-stranded DNA shows a strong positive rotation which highly decreases with denaturation. This change is analogous to the change in rotation observed when the proteins are denatured.

  4. All of the above

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TLS Online TPP Program

#Question id: 4735

#Unit 8. Inheritance Biology

In corn, three dominant alleles, called A, C, and R, must be present to produce colored seeds. Genotype A/–; C/– ; R/– is colored; all others are colorless. A colored plant AaCCRr is crossed with colorless plant aaCcRr. What proportional of offspring plant with colorless seed?

TLS Online TPP Program

#Question id: 4736

#Unit 8. Inheritance Biology

A snapdragon plant that bred true for white petals was crossed to a plant that bred true for purple petals, and all the F1 had white petals. The F1 was selfed. Among the F2, three phenotypes were observed in the following numbers

white                              240

solid-purple                    61

spotted-purple                19

Total                              320

Which of the following reason to deviation f2 phenotype ratio ?

TLS Online TPP Program

#Question id: 4737

#Unit 8. Inheritance Biology

Two independent pure line varieties having white and green phenotype in their fruit were cross, the all f1 progeny is white fruit. The F2 progeny obtain from selfing show white, yellow and green in ratio of 12:3:1. Which of the following is correct?

TLS Online TPP Program

#Question id: 4738

#Unit 8. Inheritance Biology

Red kernel color in wheat results from the presence of at least one dominant allele of each of two independently segregating genes . Kernels on rr bb plants are white, and the genotypes R— bb and rr B— result in brown kernel color. Suppose that plants of a variety that is true breeding for red kernels are crossed with plants true breeding for white kernels produced F1 were allowed to selfing .what are F2 phenotype ratio ?

TLS Online TPP Program

#Question id: 4739

#Unit 8. Inheritance Biology

Inheritance of leaf variegation in the four-o’clock plant, Mirabilis jalapa. the leaves and shoots of one variety of four-o’clock were variegated, displaying a mixture of green and white splotches. If  Flowers on the variegated branches gave rise to

TLS Online TPP Program

#Question id: 4740

#Unit 8. Inheritance Biology

Following metabolic pathway for synthesis of anthocyanin product ? Which of the following cross produced all purple phenotype in their progeny ?