List of practice Questions

E.coli cells having DNA radio labelled with $^{15}N$ were placed in culture medium containing non radioactive $N^{14}$ isotope for three generations. What will be the percentage of ratioactivity in DNA of the progeny?

Which one of the following are not strictly macromolecules although obtained in macromolecular fraction during cell content separation?

Which of these include onlyautotrophs?

After double fertilization, the secondary nucleus gives rise to

To induce feminising effect in cucurbits, which of the following combinations of plant growth regulators should be used?

According to starch-sugar conversion theory of stomatal movement, during stomatal opening

According to Oswald and Tippo's classification system. Kingdom Plantae is divided into

Polyembryony is observed in plants like Mango. Nucellar cells develop into the embryos. Which of the following is true?

Study the following lists: The correct answer is

Indicate the statement which is not correct?

The plants growing under environmental stress condition, seeds germinate while they are on the mother plant. An example for such a condition is :

Herkogamy is common in Datura plants. In Herkogamy. anther and stigma are placed at different positions so that the pollen cannot come into contact with the stigma of the same flower. Which of the following is true?

Abingdon tortoise in Galapagos islands became extinct within a decade after goats were introduced. It is an example of

A straight line through the point A (3, 4) is such that its intercept between the axes is bisected at A. Its equation is :

Which of the following is correct match of organism and respective structures?

Which of the following is a function of ethylene?

In prokaryotes, enzymes for respiration are found in

Enzymes used in detergents to remove oil stains are sourced from

Incurrent and radial canals in syconoid sponges are interconnected with the help of

Closely linked genes can be separated by

A uniform rod of mass $m$, length $L$, area of cross-section $A$ and Young's modulus $Y$ hangs from a rigid support. Its elongation due to its own weight will be

A uniform solid right circular cone of base radius $r$ is joined to a uniform solid hemisphere of radius $r$ and of the same density, so as to have a common face. The centre of mass of the composite solid lies on the common face. The height of the cone is

An $RL$ circuit in which $R = 5\,\Omega$ and $L = 4\,H$ is connected to a $22\, V$ battery at $t = 0$. For this circuit at what rate the energy is being stored in the inductor when the current in circuit is $1 \,A$ ?

A disc is placed on a surface of pond which has refractive index $5/3$. A source of light is placed $4\,m$ below the surface of liquid. The minimum radius of disc needed so that light is not coming out is

At time $t = 0$, activity of radioactive substance is $1600 \,Bq$, at $t = 8 \,s$ activity falls to $100 \,Bq$. The activity at $t = 2\, s$ is