Question 1

Assertion: Meiosis is the cell division which occurs in sexually reproducing plants. Reason: Meiotic cell division results into two cells having exactly same genetic make up.

Accepted Answer

In meiotic cell division the resultant cell does not have the exact genetic make up due to the process of crossing over. Crossing over takes place in the meiotic cell division only.

Question 2

Why do corn cobs have long tassels?

Accepted Answer

The corn cobs have long tassels which are actually stigma and style. Their long length helps them to trap pollen grains from air.

Question 3

Cucurbits and papaya plants bear staminate and pistillate flowers. Mention the categories they are put under separately on the basis of the type of flowers they bear.

Accepted Answer

Papaya is dioecious because the staminate and pistillate flowers are borne in two different plants, while cucumber is monoecious because it bears both staminate and pistillate flowers in the same plant.

Question 4

Assertion (A) In flowering plants, the structure related to sexual reproduction are flowers. Reason (R) Various embryological processes of plants occur in a flower.

Accepted Answer

Both A and R are true and R is the correct explanation of A.The structures related to sexual reproduction in flowering plants are flowers. This is because embryological processes during sexual reproduction occur in ovary, which is a part of flower.

Question 5

Among the terms listed below, those that of are not technically correct names for a floral whorl are(i) androecium                             (ii) carpel(iii) corolla                                    (iv) sepal

Accepted Answer

All the four whorls of the plant with their relative position in flower can be indicated through following diagram.Sepals collectively form a whorl, called as calyx while technically the carpel is known as gynoecium. The floral whorls formed by petals and stamens are called as corolla and androecium respectively.

Question 6

Embryo sac is to ovule as  ................... is to an anther.

Accepted Answer

The pollen grains represent the male gametophytes. As the anthers mature and dehydrate, the microspores dissociate from each other and develop into pollen grains.So, embryo sac is to ovule as pollen grains is to an anther.

Question 7

In a typical complete, bisexual and hypogynous flower the arrangement of floral whorls on the thalamus from the outermost to the innermost is

Accepted Answer

In a typical complete, bisexual and hypogynous flower the arrangement of floral whorls on the thalamus from the outermost to the innermost is(i)   The calyx, a whorl of sepals (outermost).(ii)   The corolla, a whorl of petals (inside the calyx).(iii)   The androecium, a whorl of stamens (inside the corolla).(iv)   The gynoecium, a whorl of pistils (in the centre of the flower forming inner most whorl).

Question 8

A dicotyledonous plant bears flowers, but never produces fruits and seeds The most probable cause for the above situation is

Accepted Answer

In dioecious plants, the unisexual male flower is staminate, i.e., bearing stamens only, while the female is pistillate or bearing pistils only. For the production of fruits and seeds fertilisation must take place, which is possible only in the presence of both male and female flowers.When the plant is dioecious, it will give rise to the following situations(i)   If the plant is dioecious and bears only pistillate flowers, fertilisation can take place with the help of pollinators.(ii)   If the plant is dioecious and bears only staminate flowers, fertilisation can’t take place, because female gamete is non-motile which can’t reach the male gamete in order to fuse with it.When the plant is monoecious (i.e., carrying both stamen and pistil together, it may lead to self-fertilisation and production of seed.

Question 9

Diversity of structures of the inflorescences, flower and floral parts

Accepted Answer

Diversity of structures of the inflorescences, flower and floral parts are involved in all the steps of sexual reproduction in plants, starting from pollination. So, the correct answer should be they Are adaptations to ensure formation of end products of sexual reproduction.

Question 10

Which of the following is false?

Accepted Answer

Gymnosperms, being nonflowering, do show sexual reproduction by naked seeds which is involved in sexual reproduction.

Question 11

Which of the following is the tallest flower?

Accepted Answer

Amorphophallus has the largest unbranched inflorescence in the world. The inflorescence of the talipot palm, Corypha umbraculifera, is larger, but it is branched rather than unbranched.A.titanum is endemic to Sumatra.

Question 12

Which of the following would not have an effect on flowering of a particular plant species?

Accepted Answer

Photoperiodic induction and development of flower buds and fruits depend on the age of the plant. A plant that lacks an essential nutrient cannot complete its life cycle, may not be able to develop roots, stems, leaves, or flowers properly. The temperature is from the optimal range, the lower is the rate of floral meristem development.

Question 13

In which part of a flower do both meiosis and fertilization occur?

Accepted Answer

Ovule is the female reproductive organ in plants. They host meiosis for formation of megaspores and also fertilization of pollen and egg.

Question 14

A dicotyledonous plant bears flowers but never produces fruits and seeds. The most probable cause for the above situation is -

Accepted Answer

[D] Dioecious plant with pistillate/male flower can never produce fruits or seeds.

Question 15

How many of the following have male and female reproductive organ in same plant? Sweet potato, Chara, Marchantia, Cycas, Pinus, Pea, Onion.

Accepted Answer

[B] Sweet Potato, Chara, Pinus, Pea and Onion

Question 16

Through their effect on plant growth regulators, what do the temperature and light control in the plants?

Accepted Answer

[A] Effect of temperature (low temperature) on flowering is vernalization and also relative length of day and night affects flowering called as photoperiodism. Both these involves hormone vernalin and florigen.

Question 17

The process of formation of microspore from the microspore mother cell is called megasporogenesis. The above statement is:

Accepted Answer

Microspore mother cell and pollen mother cell are the same term and form male gametes (pollens) by the process called microsporogenesis. Megasporogenesis refers to the development of megaspores from the megasporocyte, the cell that undergoes meiosis. Meiosis of the megasporocyte nucleus results in the formation of four haploid megaspore nuclei. In most taxa, meiosis is followed by cytokinesis, resulting in four megaspore cells.

Question 18

Viability of date palm seed is

Accepted Answer

Viability of date palm is 2000 yr. The oldest C14 - dated seed that has grown into a viable plant was Judean date palm (a cultivar of Phoenix dactylifera) seed about 2000 years old, recovered from excavations at Herod the Great’s palace at Masada in Israel. It was successfully sprouted in 2005 (Sallon et al, 2008).

Question 19

Diversity of structures of the inflorescence, flower and floral parts

Accepted Answer

Some flowers are adapted to be pollinated by insects, and others are adapted to be pollinated by wind. Insects are attracted to flowers because of their scent or brightly coloured petals. Many flowers produce a sweet liquid, called nectar, which insects feed on. The female part of the flower is the carpel.

Question 20

The phenomenon of two flowers, one having long stamens and short styles, and other having short stamens and long style

Accepted Answer

Heterostyly is the presence of 2 or 3 types of flowers within the same plant and such flowers differ in the length of style and stamens. Example, Primula which shows distyly.It has two types of flowers:1. Pin eyed flowers: These have long styles with short stamens.2. Thrum eyed flowers: These have a short style and long stamens.

Filters

Filters

class

subject

topic

concept

difficulty

Solution for Class 12, Biology, Sexual Reproduction in Flowering Plants

Found the solution, but did not understand the concept?

Ask my first question