Home
Class 12
BIOLOGY
Assertion : Exine of a pollen grain is m...

Assertion : Exine of a pollen grain is made up of sporopollenin which is resistant to high temperature, strong acid or alkali as well as enzymatic degradation.
Reason : Sporopollenin is absent in the region of germ pores.

A

If both assertion and reason are true and reason is the correct explanation of assertion

B

If both assertion and reason are true but reason is not the correct explanation of assertion

C

If assertion is true but reason is false

D

If both assertion and reason are false

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the assertion and reason about pollen grains, we will analyze both statements step by step. ### Step 1: Analyze the Assertion The assertion states: "Exine of a pollen grain is made up of sporopollenin which is resistant to high temperature, strong acid or alkali as well as enzymatic degradation." - **Explanation**: The assertion is correct. The exine is indeed the outer layer of the pollen grain and is composed of sporopollenin. This substance is known for its durability and resistance to various environmental factors, including high temperatures, strong acids, and enzymatic degradation. This property is crucial for the survival of pollen grains during their transport and eventual germination. ### Step 2: Analyze the Reason The reason states: "Sporopollenin is absent in the region of germ pores." - **Explanation**: This statement is also correct. Germ pores are specific areas on the pollen grain where the exine is thinner or absent, allowing for the emergence of the pollen tube during fertilization. Thus, sporopollenin is indeed absent in these regions. ### Step 3: Determine the Relationship Now, we need to determine if the reason provides a correct explanation for the assertion. - **Comparison**: While both the assertion and reason are true, the reason does not explain why the exine is made of sporopollenin or its resistant properties. The reason merely states a fact about the germ pores, which is unrelated to the assertion's focus on the composition and properties of the exine. ### Conclusion Both the assertion and reason are true, but the reason is not the correct explanation for the assertion. Therefore, the correct answer is that both the assertion and reason are true, but the reason is not a correct explanation of the assertion. ### Final Answer **Both assertion and reason are true, but the reason is not the correct explanation of the assertion.** ---
Promotional Banner

Topper's Solved these Questions

  • SEXUAL REPRODUCTION IN FLOWERING PLANTS

    NCERT FINGERTIPS ENGLISH|Exercise Sexual Reproduction In Flowering Plants|145 Videos

  • SEXUAL REPRODUCTION IN FLOWERING PLANTS

    NCERT FINGERTIPS ENGLISH|Exercise NCERT|20 Videos

  • REPRODUCTIVE HEALTH

    NCERT FINGERTIPS ENGLISH|Exercise Reproductive Health|133 Videos

  • STRATEGIES FOR ENHANCEMENT IN FOOD PRODUCTION

    NCERT FINGERTIPS ENGLISH|Exercise Strategies For Enhancement In Food Production|151 Videos

Similar Questions

Explore conceptually related problems

In pollen grains where sporopollenin is absent called germ pore.

Assertion :- Pollen grains can withstand high temperature and strong acids and alkali. Reason-Their inner layer intine is made up of sporopollenin

Sporopollenin in exine of pollen grain can be degraded

Identify the pair of wrong statements I. Intine of pollen grains is made up of sporopollenin, II.l Pollen grains are well preserved as fossils because of the presence of sporopollenin, III. Enzymes can degrade the organic material of the pollen grain exine, IV. Sporopollenin can withstand high temperature, strong acids and alkali

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

Assertion: meterbridge wire is made up of manganin Reason: The temperature coefficient of resistance is very small for manganin

Consider the following statements with respect to pollen grains (a) Exine is thin, continuous layer made up of cellulose and pectin (b) Hard outer layer called exine is made of sporopollenin (c) Sporopollenin is present in germ pores (d) Exine exhibits a fascinating array of patterns and designs. Of the above statements

The exine of a pollen grain is composed of one of the most resistant biological matieral by which pollen grains are able to withstand extremes of temperature and dessication and cannot be degraded by any enzyme is

Read the given statements. (i) Outer exine is made up of sporopollenin. (ii) Inner intine is pecto-cellulosic in nature (iii) Generative cell is bigger and contains abundant food reserve (iv) Vegetative cell is small and floats in the cytoplasm of the generative cell. Which of the given statements are not true regarding structure of pollen grain?

Assertion :- A ball is thrown from the edge of a very high clif. No matter what the angle at which it is thrown , due to air resistance, the ball will eventually end up moving vertically downward. Reason :- In horizontal direction there is a component of retarding force of air resistance alone.