Science (English Medium) Class 11 - CBSE Question Bank Solutions

A transverse section of stem is stained first with safranin and then with fast green following the usual schedule of double staining for the preparation of a permanent slide. What would be the colour of the stained xylem and phloem?

The arrangement of ovules within the ovary is known as placentation. What does the term placenta refer to? Draw various types of placentations in the flower as seen in T.S. and V.S.

Distinguish between the following:

Stele and vascular bundle

Mycorrhiza is a symbiotic association of fungus with root system which helps in ______.

1. Absorption of water
2. Mineral nutrition
3. Translocation
4. Gaseous exchange

Comment on the experimental setup

1. What does the setup demonstrate?
2. What will happen to the level of water if a blower is placed close to setup.
3. Will the mercury level fluctuate (go up/down) if phenyl mercuric acetate is sprayed on leaves?

Reaction carried out by N₂ fixing microbes include

1. \[\ce{2NH3 + 3O2 -> 2NO^{-}2 + 2H^{+} + 2H2O (i)}\]
2. \[\ce{2NO^{-}2 + O2 -> 2NO^{-}3 (ii)}\]

Which of the following statements about these equations is not true

With regard to the Biological Nitrogen Fixation by Rhizobium in association with soybean, which one of the following statement/ statements does not hold true.

Nitrogen fixation is shown by prokaryotes and not by eukaryotes. Comment.

Name a plant which lacks chlorophyll. How will it obtain nutrition?

A farmer adds Azotobacter culture to soil before sowing maize. Which mineral element is being replenished?

What is the function of leghaemoglobin in the root nodule of a legume?

Name one non-symbiotic nitrogen fixing prokaryote.

Rice fields produce an important greenhouse gas. Name it.

Complete the equation for reductive amination

\[\ce{->[?] + NH^{+}4 + NADPH ->[][?] glutamate + NADP + H2O}\]

Name the most crucial enzyme found in root nodules for N₂ fixation? Does it require a special pink coloured pigment for its functioning? Elaborate.

We find that Rhizobium forms nodules on the roots of leguminous plants. Also Frankia another microbe forms nitrogen fixing nodules on the roots of non-leguminous plant Alnus.

1. Can we artificially induce the property of nitrogen fixation in a plant – leguminous or non-leguminous?
2. What kind of relationship is observed between mycorrihiza and pine trees?
3. Is it necessary for a microbe to be in close association with a plant to provide mineral nutrition? Explain with the help of one example.

Trace the events starting from the coming in contact of Rhizobium to a leguminous root till nodule formation. Add a note on importance of leg hemoglobin

Give the biochemical events occurring in the root nodule of a pulse plant. What is the end product? What is its fate?

Photosynthetic organisms occur at different depths in the ocean. Do they receive qualitatively and quantitatively the same light? How do they adapt to carry out photosynthesis under these conditions?

In tropical rain forests, the canopy is thick and plants growing below receive filtered light. How are they able to carry out photosynthesis?