Human Reproduction — BIOLOGY STD 12 Science — Question

A population of Paramoecium caudatum was grown in a culture medium. After 5 days the culture medium became overcrowed with Paramoeium and had depleted nutrients. What will happen to the population and what type of growth curve will the population attain? Draw the growth curve.

In a maternity clinic, for some reasons the authorities are not able to hand over the two new-borns to their respective real parents. Name and describe the technique that you would suggest to sort out the matter.

The length of a DNA molecule in a typical mammalian cell is calculated to be approximately 2.2m. How is the packaging of this long molecule done to accommodate it within the nucleus of the cell?

Explain how surrogacy is helpful in case of an infertile woman.

Which one of the cell in an embryo-sac produce endosperm after double fertilisation?

1. Write two differences between Homo erectus and Homo habilis.
2. Rearrange the following from early to late geologic periods:

Carboniferous, Silurian, Jurassic.

What is oestrous cycle? Differentiate between oestrous and menstrual cycle.

What is natural selection? How is artificial selection different from natural selection? Give one example each from plants and animals where artificial selection has operated.

Mrs. Peter and Mrs. James had babies at the same hospital. Mrs. Peter took home a girl, Nancy and Mrs. James received a boy, Richard. However, Mrs. James was certain she gave birth to a girl and brought suit against the hospital. Blood tests showed that Mr. James was type O, Mrs. James was type AB and Mr. and Mrs. Peter were both type B. Nancy was type A and Richard was type O. List the possible genotypes of each individual and then indicate the correct parents for each child.
Genotypes :

1. Mrs. Peter ____________.
2. Mr. Peter ______________.
3. Nancy _____________.
4. Mrs. James _________________.
5. Mr. James ________________.
6. Richard _______________.
7. Whose baby is Nancy?
8. Whose baby is Richard?

Discuss the factors which affect the rate of decomposition.