Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

Who was the first to map chromosomes? What formed the basis for it?

Match the column A with B and rewrite correct pairs.

	A	B
i	Atlas 66	vit A
ii	Rice	vit C
iii	Spinach	protein
iv	bitter gourd	Iron

Sexual reproduction process appeared much later in organic evolution. Elaborate.

Classify the following disorders of respiratory system given below as per Column A and complete Column ‘B’. Select from the given options:
(i) Pneumonia
(ii) Asbestosis
(iii) Emphysema
(iv) Laryngitis
(v) Chronic bronchitis
(vi) Silicosis

Column A	Column B
(1) Occupational disorders	————
(2) Disorders due to smoking and air pollution	————
(3) Disorders due to viruses and bacteria	————

Explain the role of microbes in sewage treatment.

Explain the dual function of AUG codon. Give the sequence of bases it is transcribed from and its anticodon.

Mention the characteristic symptoms of chikungunya.

Explain briefly how the principle of natural selection can be applied to the development of resistance in mosquitoes for DDT.

In a cross between two tall pea plants, some of the offsprings produced were dwarf. Show with the help of Punnet square, how this is possible.

Show the graphical representation of mean annual rainfall with respect to mean annual temperature.