Question 1

Question 2Imagine all the seeds produced by a plant happen to fall under the same plant and sprout into new plants. Mention any two problems that will be faced by the new plants.

Accepted Answer

The two main problems that will faced by the new plant are:New plants will lack space for their growth because comparatively large number of plants are growing at a particular place.The new plants will face competition among themselves to get nutrient from the soil which will hamper their growth and development.

Question 2

Question 3What is a flower? Draw a typical flower and label its different parts.

Accepted Answer

Flower is a specialized shoot in which the leaves are modified into floral structures. It is the reproductive organ of the plant.Labelled diagram of a flower is shown below:

Question 3

Question 4With the help of a suitable labelled diagram, describe the structure of a dicot seed.

Accepted Answer

Taking Bean seed as an example of a dicot seed, below is its labelled diagram:The structure of a bean seed is described below:The bean seed is protected by a thin, greenish outermost covering called seed coat. It protects the seed from insects and bacteria as well as from mechanical injury.The seed coat is divided into two parts, the outer part is called Testa and inner part is called Tegmen. Tegmen is a thin membrane that lies under the Testa.On the inner concave side of the seed, there is a scar called Hilum which marks the place where the seed was attached to the fruit wall.Above the hilum is a small pore called Micropyle. The Micropyle absorbs and allows the entry of as much water as is required for germination.On removing the testa and tegmen from a soaked bean seed, the seed is made up of two fleshy seed leaves called the Cotyledons. They contain stored food material which is used by the seedling for growth.In between the two cotyledons is located the delicate embryo which consist of a Radicle and Plumule. The radical develops into a root, while the plumule develops into a shoot.

Question 4

Question 5Define germination? Name the two types of germination. Explain with examples.

Accepted Answer

The process by which an embryo within the seed becomes active and grows into a young plant is called germination. The two types of germinations are:Epigeal Germination — Put some bean seeds in moist cotton placed in a petri dish. After about two days, the radicle grows downwards and develops the roots, while the plumule grows upwards and develops into the shoot. It is seen that the cotyledons are pulled above the surface of the ground. This type of germination in which the cotyledons are pushed above the soil is called Epigeal Germination.Hypogeal Germination - Soak some maize grains in water for about 24 hours. The stored food in the endosperm is used by the radicle and plumule for their growth. The radicle grows downward while the plumule grows upward and forms the first leaf. This type of germination is called hypogeal germination, as the cotyledons remains under the soil. The plumule only comes out of the soil to form leaves of the plant.

Question 5

Question 6What are the three conditions necessary for the germination of seeds?

Accepted Answer

For the germination of the seeds the three necessary conditions are:Water — All living things required water to carry out their life processes. Most chemical reactions occur in water. So seeds also need water during germination.Oxygen — Seed also needs air for the germination of seed. The oxygen present in the air is used to oxidize the stored food and thus release energy. The energy is required for the growth of the embryo.A Suitable Temperature — It is necessary for all chemical activities assisted by enzymes. Enzymes are inactive at low temperatures and get destroyed at higher temperatures. They act best between 35° and 40°C.

Question 6

Question 7Give the main differences between Hypogeal and Epigeal germination.

Accepted Answer

Differences between Hypogeal and Epigeal germination are:HypogealEpigealThe Cotyledons remains under the soil.The Cotyledons are pushed above the soil.Epicotyl elongates faster than Hypocotyl, hence cotyledons remain below.Hypocotyl elongates faster than Epicotyl, hence cotyledons get pulled above.Example - Maize, Rice.Example - Papaya, Bean.

Question 7

Question 9(c)Give the difference in function between Filament and Style.

Accepted Answer

Difference in function between Filament and Style are:FilamentStyleThe filament bears anther at its tip which produce pollen grains. Pollen grains contain the male gametes.The style transfers the male gametes of the pollen grains into the ovary.Filament comes under the male reproductive part of the flower.Style comes under the female reproductive part of the flower.

Question 8

Question 10Draw a neat diagram of the 'longitudinal section of a maize grain' and label its seven important parts. Answer the following questions :Name the structure which divides the embryonic and endospermic region of the grain.Among the parts labelled by you above, which one of them is protienaceous in nature ?Name the food component which is stored in the endosperm.Mention the part of the seed which develops into the root.Why do we call it as a 'grain' and not as a seed or fruit ?

Accepted Answer

Diagram of Longitudinal section of a maize grain:The epithilial layer divides the embryonic and endospermic region of the grain.Aleurone layer is protinaceous in nature.Endosperm stores food in the form of starch.Radicle is the part of the seed which develops into the root.We call it 'maize grain' as the seed coat is fused together with the pericarp, making it indistinguishable.

Question 9

Question 11Given alongside is a figure of the vertical section of a typical bisexual flower. Study the same and answer the following questions :Label the guidelines 1 to 9.Which of the above labelled parts constitute the pistil? Write the numbers and names of those parts.Name the part which produces pollen grains.Is it a complete/incomplete flower ? Give reason in support of your answer.Write one important role of the part labelled as 6.

Accepted Answer

The parts 1 to 9 given in the diagram are:1 → Thalamus2 → Sepal3 → Filament4 → Anther5 → Petal6 → Stigma7 → Anther8 → Style9 → OvuleThe parts in the given figure that constitute the pistil are:6 → Stigma,8 → Style, and9 → Ovules.The anther contains pollen sacs which produce a yellow, powdery material consisting of pollen grains.The given figure shows a complete flower. This is because all four whorls viz. calyx, corolla, androecium and gynoecium are present in the same flower.One important role of Stigma is that it receives the pollen grains during pollination.

Question 10

Question 12The figure given alongside represents the vertical section of a fruit. Study the same and answer the following questions :Identify the fruit and mention whether it is a true fruit or a false fruit.Label the guidelines 1, 2, 3 and 4.Write the collective name for the parts shown as 1, 2 and 3.Name the part of the flower which matures into part 4.Which of the above labelled parts of the fruit is fleshy and edible ?

Accepted Answer

The given fruit is Mango. Mango is a true fruit as the fleshy part and the seed both develop from the ovary.The parts 1 to 4 are:1 → Epicarp2 → Mesocarp3 → Endocarp4 → SeedEpicarp, Mesocarp, and Endocarp are collectively known as the Pericarp.The ovule that contains the fertilised cell develops into a seed.Mesocarp is the sweet, fleshy and edible layer.

Question 11

Question 1Given below is a longitudinal section of a bean seed. Label the parts marked 1 to 5 and write their functions.

Accepted Answer

The parts marked 1 to 5 are:TestaPlumuleRadicleMicropyleCotyledonTheir functions are as follows:Testa — It protects the seed from insect and bacteria as well as from mechanical injury.Plumule — It develops into the shoot.Radicle — It develops into the root.Micropyle — It absorbs and allows the entry of as much water as is required for germination.Cotyledons — They contain stored food material which is used by the seedlings for growth.

Question 12

Question 6State whether the following statements are True or False.Some seeds have no cotyledons.Warmth is necessary for the germination of seeds.All seeds have two cotyledons.Oxygen is necessary for the germination of seeds.

Accepted Answer

FalseReason — Seeds always have cotyledons. Seeds are of two types — monocotyledons having a single cotyledon and dicotyledons having two cotyledons.TrueReason — Warmth or a suitable temperature is necessary for germination of seeds because enzymes are inactive at low temperatures and get destroyed at higher temperatures.FalseReason — Seeds are of two types — monocotyledons having a single cotyledon and dicotyledons having two cotyledons.TrueReason — Oxygen is required to oxidize the stored food and release energy required for the growth of the embryo.

Question 13

Question 7State one function of the following:RadicleCotyledonsEndospermMicropyle

Accepted Answer

Radicle is the part of the seed which develops into root.Cotyledons contain stored food material which is used by the seedling for growth.Endosperm stores food in the form of starch.Micropyle absorbs and allows the entry of as much water as is needed for germination.

Question 14

Question 8The three conditions necessary for germination of seeds are (tick the correct answer):Oxygen, suitable temperature and water.Good soil, water and air.Good soil, suitable temperature and light.Light, oxygen and temperature.Oxygen, carbon dioxide and light.

Accepted Answer

Oxygen, suitable temperature and waterReason — Seeds need water for germination as most chemical reactions occur in water. Oxygen is required to oxidize the stored food and release energy required for the growth of the embryo. Suitable temperature is necessary for germination of seeds because enzymes are inactive at low temperatures and get destroyed at higher temperatures.

Question 15

Question 10In the spaces provided below, draw labelled diagrams to show the three stages in the germination of any seed you have observed.Complete SeedRadicle EmergedPlumule Emerged

Accepted Answer

Labelled diagrams showing the three stages in the germination of any seed are shown below:

The Flower

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