Science 2 Marks Questions

Sexual reproduction is a process which involves production of seeds. It requires two parents. Most plants reproduce sexually with the help of flowers. The main function of a flower is to reproduce and therefore develop new seeds that can grow into new plants

When food items like bread and fruits are kept outside for a long time especially during rainy season, a cottony growth of bread mould (a fungus) is observed.

Yeast reproduces by a process called budding. A small bulb-like projection that comes out from the yeast is known as a bud. This bud grows and detaches itself from the parent cell, and then grows independently as a new plant.

Fragmentation, the splitting of cells into two parts and makes new bodies is known as fragmentation. Each fragment develops into a mature clone genetically and morphologically identical to its parent. It is a type of asexual reproduction or vegetative propagation.

Yeasts are microscopic unicellular fungi that are used to make bread, beer and wine by fermentation. Yeasts reproduce by budding (asexual reproduction), when a small bud forms and splits to form a new daughter cell, but under stress conditions they can produce spores (a form of sexual reproduction).

Unisexual flowers are those which contain either male or female reproductive part and bisexual flower has both reproductive parts (i.e. male and female) on the same flower.

The following advantages of vegetative reproduction makes it a preferred method:

• It takes less time to grow and bear flower and fruits than those produced from seeds.
• The new plants are the exact copies of parent plant because they are produced from a single parent.

The growth of fungus takes place by spores present in air, which when comes in contact with moisture on bread germinates and grow to produce new cells.

After pollination, the pollen grains fall on the surface of stigma and germinate to form a long tube, reaching the ovules inside the ovary, the egg or female gamete is present in the ovule. The outer surface of pollen grains rupture and male gametes are released to fuse with egg.

A flower is the reproductive part of flowering plants. A flower is a special part of the plant. Flowers are also called the bloom or blossom of a plant. Inside the part of the flower that has petals are the parts which produce pollen and seeds. In all plants, a flower is usually its most colourful part.

Fruits develop by many ways so there are many varieties of fruits. For example, some fruits develop without the act of fertilization. Such fruits are called arthenocarpic fruits. E.g. seedless grapes, guava, mango etc.

Layering is a method of vegetative reproduction in branches. In this method, a mature branch of parent plant is bent down and covered with soil.
The tip of the branch is kept above the ground. After few days the roots are developed from the branch buried under the soil and develops into a new plant. This method is done in the plants that have long and slender branches, e.g. jasmine.

Vegetative propagation is the ability of plants to reproduce by using vegetative parts like roots, stems and leaves. example: Yeast, Hydra, Bryophyllum reproduce by budding, algae and fungi reproduce by spores.

The coconut fruits have a very developed fibrous outer coat which enables them to float in water. They are thus carried away by flowing water to distant places.

Sexual reproduction in flowering plants involves the production of male and female gametes, the transfer of the male gametes to the female ovules in a process called pollination. After pollination occurs, fertilization happens and the ovules grow into seeds within a fruit.

The odd one out is rice. As it reproduces by sexual reproduction. All the other three, i.e. sugarcane, potato and rose reproduce through vegetative propagation.

It is a type of asexual reproduction in which new plants are produced from roots, stems, leaves and buds. Since reproduction is through the vegetative parts of the plant, it is known as vegetative propagation. Cut a branch of rose or champa with a node. This piece of branch is termed a cutting.

When male gamete present in pollen grain moves into ovules and fuse with female egg cell inside ovules and zygote is formed .This process is called fertilization.

Most ferns reproduce sexually, and that involves meiosis and fertilization. When you are thinking of the typical big fern plant, what it does is, by meiosis, produces spores, and spores have half the number of chromosomes of the big parent plant. The spores are released into the wind.

The given figure shows self-pollination, as the pollen grains from anther of the flower are transferred to the stigma of same flower.

The four whorls of a flower are: sepals which enclose the entire flower, petals which are coloured to attract insects for pollination, stamens which are the male reproductive organs and the carpels which are the female reproductive organs.

A new rose plant can be grown by cutting off a part of the stem of an existing plant, with two or more nodes, and planting it in the ground. A node is a part of the stem from where a leaf grows. This stem grows into a new rose plant.

The small plants which were not there in the garden a weak ago may have grown up due to the seed dispersal. The seeds from the tree may have fallen below or have been dispersed by wind or animals on the ground, which on germination developed into new small plants.

Reproduction is defined as the production of new individuals by parents of same species. It is important because it replaces death by maintaining the continuity of life so that species do not die out.

If all the seeds of a plant fall under the parent plant, it would result in over-crowding and saplings would experience scarcity of nutrients, light, air and space.

Fertilization in flowering plants happens through a process called pollination. Pollination occurs when pollen grains from the anther land on a stigma. Fertilization occurs when one of the sperm cells fuses with the egg inside of an ovule. After fertilization occurs, each ovule develops into a seed.

Sexual reproduction is the process in which two components male and female are involved to produce offspring of their own kind. The flower is a reproductive organ of a flowering plant.

Spore, a reproductive cell capable of developing into a new individual without fusion with another reproductive cell. Spores are agents of asexual reproduction, whereas gametes are agents of sexual reproduction. Spores are produced by bacteria, fungi, algae, and plants. Example: Mosses and ferns reproduce by spore formation.

Bryophyllum propagates vegetatively by the formation of leaf buds on the margins of a leaf. When the buds come in contact with moist soil, each bud is capable of growing into a new plant.