Practise questions for vacations... Do prepare them well..

Some questions for practice during vacations:

Q.1a) Why does endosperm development precede embryo development in angiosperm seeds?

State the role of endosperm in mature albuminous seeds.

b) Describe with the help of three labeled diagrams the different embryonic stages that include mature embryo of dicot plants.

 Q.2a)Draw a sectional view of seminiferous tubule of a human. Label the following cells in the seminiferous tubule:

i)                    Cells that divide by mitosis to imcrease their number

ii)                   Cells that undergo Meiosis I

iii)                 Cells that undergo Meiosis II

iv)                 Cells that help in the process of spermiogenesis

b) Mention the role of Leydig cells.

Q.3 Explain the ovarian and uterine events that occur during a menstrual cycle in a human female under the influence of pituitary and ovarian hormones respectively.

Q. 4 a) List three different allelic forms of gene “I’ in humans. Explain the different phenotypic   

         expressions, controlled by these three forms.

b) A woman with blood group A marries a man with blood group “O”. Discuss the possibilities of the       inheritance of the blood groups in the following starting with “yes or “no” for each:

i)                    They produce children with blood group “A” only.

ii)                   They produce children some with “O” blood group and some with “A” blood group.

Q5. Aplant with purple flowers was crossed with white flowers producing 50 plants with only purple  flowers . On selfing , these plants produced 482 plants with purple flowers and 162 with white flowers. What genetic mechanism accounts for these results? Explain.

Q6. During his studies on genes in Drosophila that were sex linked, T.H. Morgan found population phenotypic ratios deviated from expected 9:3:3:1. Explain the conclusion he arrived at.

Q7. You are given a red flower bearing pea plant and a red flower bearing snapdragon plant.How would you find the genotypes of these plants with respect to the colour of the flower?

Explain with the help of crosses. Comment upon the pattern of inheritance seen in these two plants.

Q8. Some angiosperms are said to be albuminous whereas few others are said to have a perisperm. Explain each with the help of an example.

Q9. a)How does cleistogamy ensure autogamy?

b)State one advantage and one disadvantage of cleistogamy to the plant.

Q10. How is the child affected if it has grown from the zygote formed by an XX-egg fertilized by a Y carrying sperm? What do you call this abnormality?

  Q11. How does geitonogamy differ from xenogamy? Which one between the two will lead to inbreeding  depression and why?              

May post few more questions later on. So please check by 12 th june..