BIOLOGY M.C.Q (1 Marks)

Adventive embryony is the process of the embryonic development without fertilization.
The embryo does not develops from the reproductive cells or the gametes.
They may develop from the nucellus or integumentary cells.

Pollination carried by the animals is known as zoophily.
The coloured corolla attracts insects for pollination.
It has sticky pollens which attach to the insect and are transferred from the anther to the stigma of the flower. For example, Arctium.
Pollination carried by the wind is known as anemophily.
It has lighter pollens or winged pollens which are easily carried by the wind. For example, pine.
Pollination carried by water is hydrophilly.
It has lighter pollen which is easily carried by the water currents. For example, hydrilla.

Orobanche is an obligates root parasite growing in the roots of plants like brinjal, potato, and mustard.
They have erect unbranched roots. In the embryo of these plants the plumule, radicle or cotyledons are poorly developed.
Instead, haustoria is formed for a parasitic mode of life.

Removal of stamens from bisexual parents before they burst and have shed their pollens is called emasculation.
It is performed by plant breeders to obtain the desired variety of a plant by crossing a particular plant with the desired pollen grain.

A syconium is a type of fruit in figs formed by an enlarged, fleshy, hollow receptacle with multiple ovaries on the inside surface.
It is actually a fleshy stem with a number of flowers, so it is considered both a multiple and accessory fruit.

When both the anthers and filaments are together, the condition is called as synandrous.
The synandrous condition is found in the Cucurbitaceae family.
In this condition stamen fused along both their filaments and anthers.

Because endosperms of p!nus are always haploid and is formed before fertilization in ovules.

Seeds develop from the ovules in the ovary after they have been fertilized by the male gametes from the pollen

The young shoot of a plant embryo above the cotyledons, consisting of the epicotyl and often immature leaves is the plumule. It is the future shoot.
Part of a seed embryo that develops into the shoot, bearing the first true leaves of a plant.
In most seeds, for example, the sunflower, the plumule is a small conical structure without any leaf structure.
The growth of the plumule does not occur until the cotyledons have grown above ground.

Citrus exhibits polyembryonic seed development, an apomictic process in which many maternally derived embryos arise from the nucellus surrounding the developing zygotic embryo.

In a flower, if the megaspore mother cell forms megaspores without undergoing meiosis and if one of the megaspores develops into an embryo sac, its nuclei would be diploid.

Pollination is the process by which pollen is transferred from the anther or the male part to the stigma or the female part of the plant thereby enabling fertilization and reproduction.
Fertilization is the fusion of male and female gametes.
Reproduction is the biological process by which an individual organism is produced from their parents.

Microspores are land plant spores that develop into male gametophytes.
Microspores are structures that are part of the alternation of generations in many seedless vascular cryptogams, all gymnosperms and all angiosperms.
Microspores are halpoid and are produced from diploid microsporocytes by meiosis.

Triglyceride consist of a glycerol molecule bound to three fatty acid molecules.
Triglycerides are esters. These are main components of body fat.

Endogamy is the type of pollination in which the pollen from the anthers of a flower reaches the stigma of another flower of the same plant.

Cloves represent the flower bud. They are aromatic.
They are flower buds of a tree Syzygium aromaticum belonging to the family Myrtaceae.

Microspore mother cell undergoes meiosis to produce haploid pollen grains.

The sequence of sexual reproduction in a flower is as follows:

1. Pollination is the process of transfer of pollen grains from the anther to the stigma of the flower.
2. Fertilisation is the fusion of male and female gametes which leads to the formation of the embryo.
3. The embryo is the developmental stage of a zygote which further develops into a seed.
4. The embryo develops a tough coating around it and forms seed.

Polyembryony is the occurrence of more than one embryo in a single seed.
In adventive polyembryony, there is the formation of extra embryos due to sporophytic budding.
One or more sporophytic cells, either nucellus or integuments undergo stages of embryogeny and eventually develop into mature embryos.
This kind of polyembryony is found in citrus fruits.

Autogamy is otherwise called as self fertilization.
The term autogamy is also used for pollination and describes self pollination within the same flower, distinguished from geitonogamy, transfer of pollen to a different flower on the same flowering plant, or within a single monoecious gymnospermous plant.

In a fertilised embryo sac, the haploid, diploid and triploid structures are synergid, zygote and primary endosperm nucleus.

Embryo sac is present in ovule, while pollen grains are present in anther.

Explanation: (D) Both B and D.
Flowers are sexual reproductive organ of plant because they contain male and female reproductive organ - stamen and pistil which form male and female gametes (pollen,ovule).
Flowers can be unisexual (having only stamen or pistil) or bisexual (contain both stamen and pistil).
After fertilization male and female gametes fuse to form zygote and ovary develops into fruit.
Some plants do not produce flower like-moss, fern etc. These plant reproduce by spores.

Apospory is the formation of gametophyte directly from sporophyte without the meiotic formation of spores.

Sporopollenin is a polymer, tougher than lignin but with similar properties, composed cheifly of carotenoids makes spores and pollen grains of plants resistant to biodegradation.
It is the hardest plant product.

Apomixis in plant means development of new plant without fusion of gametes.
Although seeds, in general, are the products of fertilization, a few flowering plants such as Asteraceae and grasses, have evolved this special mechanism.
Apomixis is a form of asexual reproduction that mimics sexual reproduction. But, it does not involve meiosis and fertilisation.

Cuscuta is a dicot plant but has no cotyledons because they are converted into a thread like hypocotyls, so they must find suitable hosts within a few days to survive.

Stamens are the male reproductive structure of the plant.
They produce pollen grain by the process of microsporogenesis.
Leaves are the vegetative part of plants.
The gynoecium is the female reproductive part of the plant that produces the ovum.
The pistil is synonymous with gynoecium.
Hence, pollen grains are produced by "stamens".

A staminate flower is the flower having only stamen.
It is also known as male flower.

Apomixis does not involve gamete formation and fertilization as found in amphimixis.
Adventive embryo formation is a type of apomixis in which embryos are formed from diploid integumental or nucellar cells.

The pericarp of the maize is fused with the seed coat known caryopsis.
The entire kernel is referred to as the seed.

Apocarpous gynoecium means the presence of more than one carpel and the carpels are separate or unfused.
It is a primitive condition.
Examples of apocarpous gynoecium include strawberries and buttercup.

In some seeds, Perisperm is a mass of nutritive material outside the embryo sac.
It is derived from the nucellus and deposited externally to the embryo sac.
For example, seeds of coffee, black pepper.
In maize seeds the perisperm is absent.
As maize is a monocot Coleorhiza, Coleoptile and Scutellum are found in maize.
Hence perisperm is not found in maize seed

The stamen are male reproductive organs.
They contain anther which is the site of pollen development.
Inside anther male sporogenous cell differentiates and undergoes meiosis to produce microspores that develop into pollen grains.

Monocot seed are the type of seed that have one cotyledon called scutellum.
For example, Maize.
Dicot means seed posses two cotyledons.
For example, Mango.
Wind dispersed seed are those that use wind as a medium to move from one place to another.
For example, Xanthium

Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind.
Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges and rushes.

In case of dioecious plant, male and female flowers are not usually on a single plant. Hence, emasculation may not be necessary in certain cases.

Hybridization is a technique of artificial pollination in which by spreading the stamens on female stigma the process of breeding completed.
This technique is used for developing desirable traits in different species.

Apomixis is also called as adventive embryony is the method of fertilization from cells other than egg cells.
Adventive embryony is possible when the embryo develops from the integuments or nucellus.

Stigma, ovule, embryo sac and placenta are associated with the gynoecium.

Because endosperms of p!nus are always haploid and is formed before fertilization in ovules.

Arrangement of floral whorls on the thalamus from the outermost to the innermost is Calyx, corolla, androecium and gynoecium.

Epigynous flower: Thalamus is hollowed out and fused with ovary.
Other floral organs appear at the top of ovary.
Gynoecium is inferior while other parts are superior.

Stamen is the male reproductive organ.
It consists of filament and anther.
Pollination is a phenomenon that transfers of pollen grains from anther to stigma of carpel.