(a) Draw a diagrammatic sectional view of a mature anatropous

ovule and label the following parts in it:

(i) that develops into seed coat.

(ii) that develops into an embryo after fertilization.

(iii) that develops into an endosperm in an albuminous seed.

(iv) through which the pollen tube gains entry into the embryo sac.

(v) that attaches the ovule to the placenta.

(b) Describe the characteristic features of wind pollinated flowers.

OR

(a) Draw a diagrammatic sectional view of the female reproductive system of human and label the parts

(i) where the secondary oocytes develop

(ii) which helps in collection of ovum after ovulation

(iii) where fertilization occurs

(iv) where implantation of embryo occurs.

(b) Explain the role of pituitary and the ovarian hormones in menstrual cycle in human females.

(a)

i. The part that develops into seed coat- Integument

ii. The part that develops into an embryo after fertilization-Embryo sac

iii. The part that develops into an endosperm in an albuminous seed – Nucellus

iv. The part through which the pollen tube gains entry into the embryo sac – Micropyle .

v. The part that attaches the ovule to the placenta-Funicle

(b) The characteristic features of wind pollinated flowers as follow:

• The pollen grains are light and non-sticky so that they can be transported in wind currents.

• They possess well-exposed stamens.

• The plants produce more quantity of pollen grains.

• Large feathery stigma to easily trap air-borne pollen grains.

• Wind pollinated flowers have a single ovule in each ovary and numerous flowers packed into an inflorescence.

OR

(a) The female Reproductive System Uterine fundus

i. The part where secondary oocytes develop- Ovary

ii. The part that helps in collection of ovum after ovulation-Fimbriae

iii. The part where fertilization occurs at-Fallopian tubes

iv. The part where implantation of embryo occurs-Uterus

(B) The role of pituitary and the ovarian hormones in menstrual cycle in human females:

• The cycle starts with the menstrual phase when menstrual flow occurs and it lasts for 3-5 days and it only occurs if the released ovum remains unfertilized.

• The breakdown of the endometrial lining of the uterus results in the menstrual flow.

• After the menstrual phase, the follicular phase occurs. During this phase, the primary follicles in the ovary grow to become a fully mature Graafian follicle and simultaneously the endometrium of uterus regenerates.

• These changes in the ovary and the uterus are induced by changes in the levels of pituitary and ovarian hormones.

• The secretion of gonadotropins (LH and FSH) increases during the follicular phase and promotes follicular growth and the growing follicles secrete estrogen.

• Both LH and FSH attain a peak level in the middle of the cycle (about 14thday) that is an ovulation (ovulatory phase).

• The remaining parts of the Graafian follicle get converted as the corpus luteum.

• The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium.