Human Reproduction — BIOLOGY STD 12 Science — Question

With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.

The following is the illustration of the sequence of ovarian events (a – i) in a human female.

What is the difference between “d” and “e” ?

How bacterial cells are made competent to take up DNA?

What is lacoperon. Draw its labelled diagram. Explain its structure and mechanism of action of lac operon.

What is the inheritance pattern observed in the size of starch grains and seed shape of Pisum sativum? Workout the monohybrid cross showing the above traits. How does this pattern of inheritance deviate from that of Mendelian law of dominance?

Answer the following questions:
Mention the functions of acrosome and middle piece.

1. List the three different allelic forms of gene ‘I’ in humans. Explain the different phenotypic expressions, controlled by these three forms.
2.  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:

1. They produce children with blood group ‘A’ only.
2. They produce children, some with 'O' blood group and some with 'A' blood group.

What functions do the female reproductive system perform?

Draw a labelled sketch of L.S. of pistil showing the progamous type of fertilization.

1. One of the sperms is observed to penetrate 'a' of the ovum, as shown in the above diagram. Name 'a'.
2. How is the sperm able to do so?
3. Where exactly in the fallopian tube does this occur?
4. Explain the events thereafter up to morula stage.