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

Are there any homologous organs in male and female reproductive system? If yes, give examples.

In our society the women are often blamed for giving birth to daughters. Can you explain why this is not correct?

Name and explain the technique that helps in separation of DNA fragments for recombinant DNA technology experiments. How can these separated DNA fragments be visualised?

OR

1. Name the technique used for the separation of DNA fragments.
2. Write the type of matrix used in this technique.
3. How is the separated DNA visualised and extracted for use in recombinant DNA technology?

One of the codons on mRNA is AUG. Draw the structure of tRNA adapter molecule for this codon. Explain the uniqueness of this tRNA?

The following illustrates the linking of DNA fragments A DNA fragments:

1. Write the name of A and B.
2. Complete the palindrome, which is recognized by EcoRI.
3. Write the name of the enzyme that can link the two DNA fragments.

Organisms at a higher trophic level have less energy available. Comment.

Where and how does the primary succession occur? Explain.

(a) Write the conclusions drawn by Alexander von Humbolt based on his extensive exploration of South America.
(b) Study the graph given below :

According to Alexander von Humbolt, what do the symbols S, A, C, and Z used in graphs indicate in the context of a species and region relationship?

Draw a transverse sectional view of an apple and label the following parts along with their technical names:

1. Edible part.
2. Encloses the embryo.
3. Forms the fruit wall.