Define aneuploidy. How is it different from polyploidy? Describe the individuals having following chromosomal abnormalities.
Trisomy of 21st Chromosome
XXY
X0.

Define aneuploidy. Name the aneuploid disease which occurs as a result of following chromosomal abnormalities: Presence of additional copy of chromosome X i.e., XXX.

What happens when we subtract an interger from another integer ? Can we say that the difference is also an integer ? Observe the following table and complete it . "Statement" " " "Observation" (i) 7-9=-2 " " "Result is an interger" (ii) 17-(-21)=....... " " ............... (iii) (-8)-(-14)=6 " " "Result is an integer" . (iv) (-21)-(-10)=...... " " .............. (v) 32 -(-17)=..... " " ............ (vi) (-18)-(-18)=.... " "............... (vii) (-29)-0=...... " " ............... What do you observe ? Is there any pair of integer whose difference is not an integer ? Can we say integers are close under subtraction ?

Read the given passage and answers following questions : A catalytic process in which the catalyst and the reactants are present in different phases is known as a heterogeneous catalysis. This heterogeneous catalytic action can be explained in terms of the adsorption theory. The mechanism of catalysis involves the following steps: (i) Adsorption of reactant molecules on the catalyst surface. (ii) Occurrence of a chemical reaction through the formation of an intermediate. (iii) De-sorption of products from the catalyst surface (iv) Diffusion of products away from the catalyst surface. In this process, the reactants are usually present in the gaseous state and the catalyst is present in the solid state. Gaseous molecules are then adsorbed on the surface of the catalyst. As the concentration of reactants on the surface of the catalyst increases, the rate of reaction also increases. In such reactions, the products have very less affinity for the catalyst and are quickly desorbed, thereby making the surface free for other reactants. How many steps involved in mechanism of catalysis ?