How do Organisms Reproduce - Sexual Reproduction in Plants Flashcards
what is the sexual part of the plant
the flower
what are flowering plants called? what are non-flowering plants called?
flowering plants- angiosperms
non-flowering plants- gymnosperms
what are the main parts of the flower
-carmen/pistil
-stamen
-petals
-sepals
what is the carpel or pistil? what is its function
the pistil is the female reproductive part of the flower. It is responsible for production of the egg cells
what is the stamen? what is its function
the stamen is the male reproductive organ of the flower. It is responsible for producing the male gametes- sperm cells
what is the function of petals
petals make the flower colourful and attractive in order to attract insects like bees/butterflies and birds for the purpose of pollination.
what is the function of the sepals
it is responsible for the protecting the flower at its young bud stage.
what are bisexual flowers. GIVE SOME EXAMPLS
flowers that have both the female and male reproductive parts are called bisexual flowers. Examples
: all the famous plant you know of such as roses, sunflowers, lilies, lotuses, hibiscus, marigols, daffodils, mango flower,mustard
what are unisexual flowers? GIVE SOME EXMAPL
S
flowers that have only one: either the male or female reproductive organ are called unisexual plants. Examples: all the flowers of big fruits or big vegetables, flowers of watermelon,papaya, bottlegourd,jackfruit,pumpkin
What are the parts of the stamen
Stamen is divided into two parts. The long stalk is called the filament while the blob on the top of the filament is called as the anther.The filament supports the anther and raises it higher(close to stigma) so that the bee/bbird can reach it. The anther produces the yellow coloured pollen grains which contain the male gamete sperm cells.these pollen grains are sticky.
What are the parts of the pistil
The swollen bottom part is the ovary, middle elongated part is the style and the terminal part which may be sticky is the stigma. The ovary contains ovules and each ovule has an egg cell.
Define pollination
Pollination is the act of transferring pollen grains from the anther to the stigma
Define self pollination
If the pollen grains are transferred from the anther to the stigma of the same plant, then it is called self pollination.There are two types of self pollination:
i) when the pollen is transferred within the same plant
ii)when it is transferred from a different flower in the same plant
Define cross pollination
The transfer of pollen grains from the anther of one flower to the stigma of the flower of another plant of the same species is called cross pollination
Explain how pollination is achieved by agents: wind
The pollen grains are carried by the wind,the pollen grains are sticky or have hairs which sticks to the stigma-which is also often sticky-when it comes in contact
Explain how animals contribute to pollination
The flowers have attractive colours, odour or nectar which attract the various animals such as bees, butterflies,moths and birds.
When the animals go to suck on the nectar, the sticky pollen grains from the anther get stuck to the animal’s body,
When the animal goes and sits on another flower, the pollen grains are transferred to the sticky stigma of the other plant.
what happens after the pollen lands on stigma
the pollen then absorbs some of the secretions secreted by the stigma and then germinates It grows a large tube which directs the sperms from the pollen into the ovary straight into the ovules.
how is the pollen tube directed towards the right ovule?
the ovule secretes some substances which is sensed by the pollen tube and grows towards it. this phenomena is called chemitropism.
define fertilisation
the fusion of the male gamete cell(sperm) with the female gamete cell(egg cell) in the ovary is called fertilisation
define zygote
the product cell of the fusion of the male and female gamete cells is called the zygote, which has the capability to grow into a new plant.
what happens to the pollen tube after the formation of zygote
the pollen tube disintegrates.
what does do zygote do after its formation
the zygote divides multiple times within the ovule to form an embryo.
what is the seed
once the zygote forms within the ovule. The ovule develops a tough coat and converts into a seed.
what happens after formation of seed
the unfertilised ovules disintegrate, the stamens shrivel up and the petals and sepals fall off.
the ovary starts swelling and becomes bigger and bigger. This ovary then grows into the fruit.
what are the advantages of seed-formation
The seeds protect the embryo from harsh environmental conditions.
They provide nourishment and parental care to the developing embryo.
The dispersal of the seeds to far-off places prevents competition among the members of the same species, thus preventing their extinction.
what happens when the seed is sown?
when the fruit seed is sown:
-the seed absrobs water through micropyle
-rupture of seed coat
-emergence of radicle
-emergence of plumule
-the root develops from the radicle
-the shoot develops from the plumule
-the cotyledons grow and swell, in order to provide nourishment.
-shoot then develops true leaves which photosynthesize and produce food.
-the cotyledons then drain and shrink gradually.
define germination
the process of a new plant growing from an embryo in the seed under suitable conditions is called germination.
