Chapter 1: Sexual Reproduction in Flowering Plants Assertion-Reason Questions | biology Class 12 CBSE

ByteNotes

Chapter 1: Sexual Reproduction in Flowering Plants Assertion-Reason Questions | biology Class 12 CBSE | ByteNotes.in

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 1

Logic Check

Assertion (A): Pollen grains are well-preserved as fossils. Reason (R): The exine of pollen grains is made of sporopollenin, which is highly resistant to degradation.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 2

Logic Check

Assertion (A): Tapetal cells are often bi-nucleate or multinucleate. Reason (R): Tapetal cells undergo meiosis to produce extra nuclei for nourishing pollen grains.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 3

Logic Check

Assertion (A): Geitonogamy is functionally cross-pollination. Reason (R): Geitonogamy involves transfer of pollen from one flower to another flower on the same plant, resulting in genetic variation.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 4

Logic Check

Assertion (A): In angiosperms, double fertilisation occurs. Reason (R): One male gamete fuses with the egg cell and the other male gamete fuses with two polar nuclei.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 5

Logic Check

Assertion (A): The zygote is dormant for some time before embryo development begins. Reason (R): The zygote waits for endosperm development so that nutrients are available for the growing embryo.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 6

Logic Check

Assertion (A): Apomixis is commercially important in agriculture. Reason (R): Apomixis allows farmers to maintain hybrid vigour over successive generations without buying new hybrid seeds each season.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 7

Logic Check

Assertion (A): Cleistogamous flowers always produce seeds by cross-pollination. Reason (R): Cleistogamous flowers never open and pollen is shed inside the closed flower onto the stigma.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 8

Logic Check

Assertion (A): Apple is called a false fruit. Reason (R): The fleshy edible part of apple develops from the thalamus and not from the ovary.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 9

Logic Check

Assertion (A): Wind-pollinated flowers produce large quantities of pollen. Reason (R): Wind pollination is an inefficient process and excess pollen compensates for the uncertainty of the pollen reaching the stigma.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 10

Logic Check

Assertion (A): Endosperm development precedes embryo development in most angiosperms. Reason (R): Endosperm provides nutrition to the developing embryo, so it must form first to support embryo growth.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 11

Logic Check

Assertion (A): Pollen grains of rice lose viability within 30 minutes of their release. Reason (R): Rice is a cleistogamous plant where pollen grains are never exposed to the outside environment.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 12

Logic Check

Assertion (A): The mature embryo sac of the Polygonum type is 7-celled and 8-nucleate. Reason (R): The central cell contains two polar nuclei which accounts for the discrepancy between the number of cells and nuclei.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 13

Logic Check

Assertion (A): Synergids help in the entry and guidance of the pollen tube into the embryo sac. Reason (R): Synergids possess a filiform apparatus that secretes chemicals to attract the pollen tube.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 14

Logic Check

Assertion (A): Self-incompatibility prevents self-fertilisation in some flowering plants. Reason (R): In self-incompatible plants, the pollen tube is inhibited from growing in the style when pollen from the same plant is used.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 15

Logic Check

Assertion (A): In pea seeds, no endosperm is found in the mature seed. Reason (R): In pea, the endosperm is completely consumed by the developing embryo during seed maturation.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 16

Logic Check

Assertion (A): Sporopollenin is absent in the germ pores of pollen grains. Reason (R): Germ pores serve as the exit point for the pollen tube during germination.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 17

Logic Check

Assertion (A): Perisperm is found in seeds of black pepper (Piper). Reason (R): Perisperm is the persistent nucellus that serves as a nutritive tissue and is triploid in nature.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 18

Logic Check

Assertion (A): Xenogamy is genetically more significant than autogamy or geitonogamy. Reason (R): Xenogamy involves transfer of pollen between genetically different plants, leading to new gene combinations.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 19

Logic Check

Assertion (A): Polyembryony is commercially exploited in citrus. Reason (R): Nucellar embryos produced by polyembryony in citrus are genetically identical to the mother plant and are used as true-to-type rootstocks.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 20

Logic Check

Assertion (A): The generative cell of a pollen grain is spindle-shaped with dense cytoplasm. Reason (R): The generative cell eventually divides to produce two male gametes needed for double fertilisation.

Reasoning Options

ByteNotes

Premium Access

Unlock all Assertion-Reason Questions

You are viewing 20 free assertion-reason questions from this chapter. Upgrade to Premium to unlock the remaining 20 questions.

Upgrade to Premium20 questions locked

Chapter sections

Chapter 1: Sexual Reproduction in Flowering Plants | Assertion-Reason

Assertion (A): Pollen grains are well-preserved as fossils. Reason (R): The exine of pollen grains is made of sporopollenin, which is highly resistant to degradation.

Assertion (A): Tapetal cells are often bi-nucleate or multinucleate. Reason (R): Tapetal cells undergo meiosis to produce extra nuclei for nourishing pollen grains.

Assertion (A): Geitonogamy is functionally cross-pollination. Reason (R): Geitonogamy involves transfer of pollen from one flower to another flower on the same plant, resulting in genetic variation.

Assertion (A): In angiosperms, double fertilisation occurs. Reason (R): One male gamete fuses with the egg cell and the other male gamete fuses with two polar nuclei.

Assertion (A): The zygote is dormant for some time before embryo development begins. Reason (R): The zygote waits for endosperm development so that nutrients are available for the growing embryo.

Assertion (A): Apomixis is commercially important in agriculture. Reason (R): Apomixis allows farmers to maintain hybrid vigour over successive generations without buying new hybrid seeds each season.

Assertion (A): Cleistogamous flowers always produce seeds by cross-pollination. Reason (R): Cleistogamous flowers never open and pollen is shed inside the closed flower onto the stigma.

Assertion (A): Apple is called a false fruit. Reason (R): The fleshy edible part of apple develops from the thalamus and not from the ovary.

Assertion (A): Wind-pollinated flowers produce large quantities of pollen. Reason (R): Wind pollination is an inefficient process and excess pollen compensates for the uncertainty of the pollen reaching the stigma.

Assertion (A): Endosperm development precedes embryo development in most angiosperms. Reason (R): Endosperm provides nutrition to the developing embryo, so it must form first to support embryo growth.

Assertion (A): Pollen grains of rice lose viability within 30 minutes of their release. Reason (R): Rice is a cleistogamous plant where pollen grains are never exposed to the outside environment.

Assertion (A): The mature embryo sac of the Polygonum type is 7-celled and 8-nucleate. Reason (R): The central cell contains two polar nuclei which accounts for the discrepancy between the number of cells and nuclei.

Assertion (A): Synergids help in the entry and guidance of the pollen tube into the embryo sac. Reason (R): Synergids possess a filiform apparatus that secretes chemicals to attract the pollen tube.

Assertion (A): Self-incompatibility prevents self-fertilisation in some flowering plants. Reason (R): In self-incompatible plants, the pollen tube is inhibited from growing in the style when pollen from the same plant is used.

Assertion (A): In pea seeds, no endosperm is found in the mature seed. Reason (R): In pea, the endosperm is completely consumed by the developing embryo during seed maturation.

Assertion (A): Sporopollenin is absent in the germ pores of pollen grains. Reason (R): Germ pores serve as the exit point for the pollen tube during germination.

Assertion (A): Perisperm is found in seeds of black pepper (Piper). Reason (R): Perisperm is the persistent nucellus that serves as a nutritive tissue and is triploid in nature.

Assertion (A): Xenogamy is genetically more significant than autogamy or geitonogamy. Reason (R): Xenogamy involves transfer of pollen between genetically different plants, leading to new gene combinations.

Assertion (A): Polyembryony is commercially exploited in citrus. Reason (R): Nucellar embryos produced by polyembryony in citrus are genetically identical to the mother plant and are used as true-to-type rootstocks.

Assertion (A): The generative cell of a pollen grain is spindle-shaped with dense cytoplasm. Reason (R): The generative cell eventually divides to produce two male gametes needed for double fertilisation.

Unlock all Assertion-Reason Questions

Practice in Quiz Mode