Which of the following is incorrect regarding pollen grains in angiosperms?
1. | The exine is made up of sporopollenin. |
2. | Generative cell divides meiotically to give rise to four gametes. |
3. | In over 60% of angiosperms, pollen grains are shed at the 2-celled stage. |
4. | Pollen grains of many species can cause severe allergies in humans. |
The germ pore in the pollen wall:
1. | is an aperture in the pollen intine that allows the pollen tube to exit. |
2. | is the name of the nucleus of the microspore mother cell. |
3. | is formed where sporopollenin is located in the exine. |
4. | is an aperture in the pollen exine that allows the pollen tube to exit. |
Match each item in Column I with one in Column II and select the correct answer from the codes given:
A. |
Pollen exine |
P. |
Cellulose and pectin |
B. |
Pollen intine |
Q. |
Sporopollenin |
C. |
Antipodals |
R. |
Nutrition to the embryo sac |
D. |
Synergids |
S. |
Pollen tube guidance |
A. |
B. |
C. |
D. |
|
1. |
P |
Q |
R |
S |
2. |
Q |
P |
S |
R |
3. |
Q |
P |
R |
S |
4. |
P |
Q |
S |
R |
An organic substance that can withstand environmental extremes and cannot be degraded by any enzyme is:
1. | Cuticle | 2. | Sporopollenin |
3. | Lignin | 4. | Cellulose |
Tapetum :
I. | Is a layer of nutritive cells that are found within the microsporangium. |
II. | The cells are usually bigger and normally have more than one nucleus per cell because mitosis is not normal in them. |
III. | Helps in pollen wall formation, transportation of nutrients to the inner side of the anther, synthesis of callose enzyme for separation of microspore tetrads. |
Of the above statements, the correct ones are:
1. | I and II only | 2. | I and III only |
3. | II and III only | 4. | I, II, and III |
Identify the incorrect statement regarding angiosperm:
1. | A typical anther is bilobed and dithecous |
2. | Cells of tapetum are nourishing to developing pollen grains |
3. | In over 60% of angiosperms pollen grains are shed at the 3-celled stage |
4. | It is possible to store many pollen grains by cryopreservation |