Module: | Pre-fertilization: Micro/Megasporogenesis
Q2: Consider the following statements regarding the anatomy of the pollen grain wall:
1. The outer layer, called the exine, is composed of sporopollenin, which is highly resistant to organic acids and high temperatures.
2. Germ pores are prominent apertures on the exine where sporopollenin is absent.
3. The inner layer, called the intine, is a thick, discontinuous layer made primarily of chitin and pectin.
Which of the above statements is/are correct?
2. Germ pores are prominent apertures on the exine where sporopollenin is absent.
3. The inner layer, called the intine, is a thick, discontinuous layer made primarily of chitin and pectin.
Which of the above statements is/are correct?
✅ Correct Answer: A
The correct option is A. Statements 1 and 2 are correct, whereas Statement 3 is incorrect.
The pollen grain represents the male gametophyte and possesses a distinct two-layered wall called the sporoderm.
The exine is the hard outer layer made of sporopollenin, one of the most resistant organic materials known to biology, allowing pollen to fossilize well.
Structurally, the exine has gaps called germ pores where sporopollenin is absent; these are crucial for the later emergence of the pollen tube.
The intine is the inner wall, but contrary to Statement 3, it is a thin, continuous layer composed of cellulose and pectin, not chitin.
In the context of previous board and medical entrance exams, the composition of the intine versus the exine is a fundamental discriminator for students, directly linking structural biochemistry to the physiological mechanism of pollen germination.
The pollen grain represents the male gametophyte and possesses a distinct two-layered wall called the sporoderm.
The exine is the hard outer layer made of sporopollenin, one of the most resistant organic materials known to biology, allowing pollen to fossilize well.
Structurally, the exine has gaps called germ pores where sporopollenin is absent; these are crucial for the later emergence of the pollen tube.
The intine is the inner wall, but contrary to Statement 3, it is a thin, continuous layer composed of cellulose and pectin, not chitin.
In the context of previous board and medical entrance exams, the composition of the intine versus the exine is a fundamental discriminator for students, directly linking structural biochemistry to the physiological mechanism of pollen germination.