Grignard reagents (RMgX) are highly reactive towards moisture. If water is present, it reacts with the Grignard reagent, forming an alkane instead of undergoing the desired reaction. This is why anhydrous conditions are necessary during preparation and storage.
Explain with the help of chemical reactions: (I) Acetone is treated with semicarbazide.
Would you expect benzaldehyde to be more reactive or less reactive in nucleophilic addition reactions than propanal? Justify your answer.
The sequence of nitrogenous bases in a segment of a coding strand of DNA is
5' – AATGCTAGGCAC – 3'. Choose the option that shows the correct sequence of nitrogenous bases in the mRNA transcribed by the DNA.
(a) Write the palindromic nucleotide sequence for following sequence of DNA segment:
5' – GAATTC – 3'
(b) Name the restriction endonuclease that recognizes this sequence.
(c) How are sticky ends produced? Mention their role.
Study the graphs given below for Case 1 and Case 2 showing different levels of certain hormones and answer the question that follows:
(a) Which hormone is responsible for the peak observed in Case 1 and Case 2? Write one function of that hormone.
(b) Write changes that take place in the ovary and uterus during follicular phase.
Student to attempt either sub-part (c) or (d):
(c) Name the hormone Q of Case 2. Write one function of hormone Q.
OR
(d) Which structure in the ovary will remain functional in Case 2? How is it formed?
1. Perform a cross between two sickle cell carriers. What ratio is obtained between carrier, disease free and diseased individuals in F1 progeny? Name the nitrogenous base substituted, in the haemoglobin molecule in this disease.
2. Explain the difference in inheritance pattern of flower colour in garden pea plant and snap-dragon plant with the help of monohybrid crosses.
OR,
Explain with the help of well-labelled diagrams how lac operon operates in E. coli :
1. In presence of an inducer.
2. In absence of an inducer.