Male gametophyte in angiosperms produces
1. two sperms and a vegetative cell
2. single sperm and a vegetative cell
3. single sperm and two vegetative cells
4. three sperms
Which one of the following statements is not true?
1. Pollen grains are rich in nutrients and they are used in the form of tablets and syrups
2. Pollen grains of some plants cause severe allergies and bronchial afflictions in some
people
3. The flowers pollinated by flies and beetles secrete foul odour to attract them
4. Honey is made by bees by digesting pollen collected from flowers
Pollen grains are shed at which stage?
(1) 2 celled
(2) 3 celled
(3) Usually at 2-celled, but sometimes 3-celled
(4) Single celled stage
False fruit in an apple is formed from
(1) receptacle
(2) thalamus
(3) peduncle
(4) petals.
Seed of castor is
(1) non-endospermic, exalbuminous
(2) endospermic albuminous
(3) endospermic exalbuminous
(4) non-endospermic albuminous.
During formation of which of the following free nuclear division occurs?
(1) Flower
(2) Endosperm
(3) Gametes
(4) Fruit
Pollen grains are able to withstand extremes of temperature and dessication because their exine is composed of
(1) cutin
(2) suberin
(3) sporopollenin
(4) callose
The pollen tube usually enters the embryo sac
(1) through one of the synergids
(2) by directly penetrating the egg
(3) between one synergid and central cell
(4) by knocking off the antipodal cells
Double fertilization involves
(1) fertilization of the egg by two male gametes
(2) fertilization of two eggs in the same embryo sac by two sperms brought by one pollen tube
(3) fertilization of the egg and the central cell by two sperms brought by different pollen tubes
(4) fertilization of the egg and the central cell by two sperms brought by the same pollen tube.
What is the charasteristic of tapetum ?
(1) It does not store food.
(2) It is multi-nucleated.
(3) It is multi-layered structure.
(4) It nourishes the megaspore.