Biology
Given below is the internal structure of an ovule. Read the information below the diagram and fill in the blanks:
Ovule is located in the inner part of the ovary. It is destined to become the seed and the ovary to become the fruit. The number of ovules in the ovary vary from species to species. It can be one or more.
Each ovule has one or two protective coverings, the integuments. The integuments leave a small opening called the (a) …………… at one end. Enclosed by the integuments is the (b) ………………(a mass of food laden cells), and further inside it, is the embryo sac. Embryo sac contains one (c) …………… and two (d) …………… at one end. Three (e) …………… cells are found at the opposite end of embryo sac.
Answer
Each ovule has one or two protective coverings, the integuments. The integuments leave a small opening called the Micropyle at one end. Enclosed by the integuments is the Nucellus (a mass of food laden cells), and further inside it, is the embryo sac. Embryo sac contains one Egg cell and two Synergids at one end. Three Antipodal cells are found at the opposite end of embryo sac.
Related Questions
Assertion (A): One polar nucleus fuses with two sperm nuclei of a flower and develop into an endosperm during the process of fertilization.
Reason (R): The large central cell of the embryo sac contains two polar nuclei, which fuse with one male nucleus. This process is termed as 'triple fusion'.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Assertion (A): The process of removal of anthers in young flowers is termed as 'emasculation'.
Reason (R): Emasculation is mainly performed during artificial pollination to produce the desired variety of the plants.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
State the name of the chief pollinating agent against the corresponding plant by choosing from those given in brackets.
- Dahlia……(Crow, butterflies, mosquito).
- Maize…….(Bees, locusts, rain, wind).
- Vallisneria………(Wind, water, ants, rabbits).
Fill in the blanks with suitable words.
- Transfer of pollen grains from anthers to stigma of the same flower is called …………… .
- Different timings for maturation of gynoecium and androecium, is called …………… .
- …………… is a water-pollinated flower.