Mineral Nutrition — BIOLOGY STD 11 Science — Question

1. Explain the role of loop of Henle in urine formation in humans.
2. Draw a labelled diagram of a nephron.

Every nutrient comes from the abiotic component of the ecosystem. These nutrients are converted by green plants into useful substances and finally go to other living beings through the food chain. Finally, after the death of plants and animals; decomposers send them back to the environment. Thus the balance of various components of the ecosystem is maintained. In your view which of the following is the correct approach? What is the importance of balance of ecosystem for us?

1. We should protect the ecosystem so that its balance is maintained.
2. We should enjoy our life and let the nature do its job of maintaining the balance in the ecosystem.

Justify at what extent the phylogenetic relationship is useful as a criterion for classification.

There is a myth that immediately after heavy rains in forest, mushrooms appear in large number and make a very large ring or circle, which may be several metres in diameter. These are called as ‘Fairy rings’. Can you explain this myth of fairy rings in biological terms?

Define differentiation? Also give details about how can you distinguish between dedifferentiation and redifferentiation?

Differentiate between obligate categories and intermediate categories. Demonstrate with the help of a flowchart.

With respect to rib cage, explain the following: Bicephalic ribs. True ribs. Floating ribs.

Explain the difference between the initial stages of mitosis and meiosis.

What is the difference between florigen and other plant growth hormones?

(i) Write three differences between protein hormones and steroid hormones.
(ii) Draw a labelled diagram depicting the mechanism of hormone action.