Immunity in our body is of two types: (i) Innate immunity and (ii) acquired immunity. Innate immunity is a non-specific defence mechanism, whereas acquired immunity is pathogen-specific; it is called specific immunity too. Acquired immunity is characterised by memory. Antibodies are specific to antigens and there are different types of antibodies produced in our body: they are IgA, IgE, IgG and IgM. It shows primary response when it encounters the pathogen for the first time and secondary response during the subsequent encounters with the same Antigen/Pathogen. (a) Name the two types of specialised cells which carry out the primary and secondary immune response. (b) Why is the antibody-mediated immunity also called as humoral immune response? Attempt either sub-part (c) or (d): (c) The organ transplants are often rejected if taken from suitable compatible persons. (i) Mention the characteristic of our immune system that is responsible for the graft rejection. (ii) Name the type of immune response and the cell involved in it. OR (d) How is active immunity different from passive immunity?
A square Lamina OABC of length 10 cm is pivoted at \( O \). Forces act at Lamina as shown in figure. If Lamina remains stationary, then the magnitude of \( F \) is:
Considering Bohr’s atomic model for hydrogen atom :(A) the energy of H atom in ground state is same as energy of He+ ion in its first excited state. (B) the energy of H atom in ground state is same as that for Li++ ion in its second excited state. (C) the energy of H atom in its ground state is same as that of He+ ion for its ground state. (D) the energy of He+ ion in its first excited state is same as that for Li++ ion in its ground state.
The correct orders among the following are: [A.] Atomic radius : \(B<Al<Ga<In<Tl\) [B.] Electronegativity : \(Al<Ga<In<Tl<B\) [C.] Density : \(Tl<In<Ga<Al<B\) [D.] 1st Ionisation Energy : In\(<Al<Ga<Tl<B\) Choose the correct answer from the options given below :
The total number of structural isomers possible for the substituted benzene derivatives with the molecular formula $C_7H_{12}$ is __
Which of the following is the correct IUPAC name of the given organic compound (X)?The structure of compound $ X $ is as follows:
$ \text{H}_3\text{C} - \text{CH}_3 - \text{CH} = \text{CH} - \text{H} - \text{Br} $