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

Describe three important aspects of Biodiversity.###Explain the three important levels of biodiversity.

1. Write the palindromic nucleotide sequence for the following DNA segment:

5' - GAATTC - 3'

2. Name the restriction endonuclease that recognises this sequence.
3. How are 'sticky ends' produced? Mention their role.

Differentiate between homology and analogy. Give one example of each.

1. Mention the property that enables the explants to regenerate into a new plant.
2. A banana herb is virus-infected. Describe the method that will help in obtaining healthy banana plants from this diseased plant.

Given below are pairs of diseases and causative organisms. Which out of these is not a matching pair and why?
Filariasis: Wucheraria
Ringworm: Ascaris
AIDS: Human Immuno Virus
Malaria: Plasmodium

What is the difference between gaseous and sedimentary cycles?

What are 'cry-proteins'? Explain with the help of a suitable example how it works as a biopesticide.

1. Name the organic material exine of the pollen grain is made up of. How is this material advantageous to pollen grain?
2. Still it is observed that it does not form a continuous layer around the pollen grain. Give reason.
3. How are 'pollen banks' useful?

Two types of aquatic organisms in a lake show specific growth patterns as shown below, in a brief period of time. The lake is adjacent to an agricultural land extensively supplied with fertilizers.
Answer the questions based on the facts given above:

1. Name the organisms depicting the patterns A and B.
2. State the reason for the growth pattern seen in A.
3. Write the effects of the growth patterns seen above.

Differentiate between benign tumor and malignant tumor.