(a) Where is microsporangium located in an angiosperm? State the functions of tapetum and the other three layers of microsporangium.

(b) Describe the structure of the male gametophyte produced as a result of microsporogenesis.

(c) State the functions of each part of the male gametophyte.

OR

When and how do the following get to form in human females? State their functions.

(a) Corpus luteum

(b) Placenta

a)

• The microsporangium is located in the lobe of the anther.

• The tapetum provides nutrition or nourishes the developing pollen grain.

• The three layers of the microsporangium are:

• Epidermis

• Endothecium

• Middle layer

• These three layers aid in dehiscence and protection of the microsporangium.

b) The pollen grain is the male gametophyte. It has the following structures:

• The outer wall layer called the exine.

• The inner wall layer called the intine.

• The vegetative cell

• The generative cell

c) Functions:

• Exine: Provides protection to the pollen grain

• Intine: Provides protection to the pollen grain

• Vegetative cell: It reserves food material and helps in the formation of the pollen tube.

• Generative cell: It leads to the formation of two male gametes.

OR

a) Corpus luteum:

• It is formed during the luteal phase i.e. after ovulation. The luteal phase is also known as the secretory phase.

• It is formed when the Graafian follicle ruptures. The follicular cells of this ruptured Graafian follicle form the corpus luteum.

• The corpus luteum secretes progesterone. Progestrone helps to maintain the endometrium lining of the uterus.

b) Placenta:

• The placenta forms after the embryo gets implanted into the uterine wall.

• It is formed when the Chorionic villi of the blastocyst and uterine tissue interdigitate together.

• It supplies oxygen and nutrient and removes carbon dioxide and excretory material, also acts as an endocrine tissue and produces several horomones like hCG, hPL etc.