Ovulation

Inside the ovary, eggs grow in small fluid-filled sacs called follicles. Each month, one follicle ripens fully. The ripe one is called a Graafian follicle. At ovulation it bursts and lets the egg out. The egg then moves into the oviduct, where it may meet a sperm.

The empty follicle left behind does not go to waste. It turns into a yellow body called the corpus luteum. This makes the hormone progesterone, which keeps the lining of the uterus ready for a baby.

• Ovulation: the egg leaves the ovary.
• Fertilisation: a sperm joins the egg, in the oviduct.
• Implantation: the young embryo sinks into the wall of the uterus.

A small example

Take a cycle of 28 days. Ovulation usually comes near the middle, around day 14. If no sperm meets the egg, the corpus luteum breaks down and the uterus lining is shed.

Where marks go

Those three words are easy to swap. The 2024 ICSE Biology paper showed a section of the ovary. It asked for the process that releases the egg, and for the structure left behind. CISCE's 2024 Biology report names "implantation" written for ovulation, and "graafian follicle" written for corpus luteum.

The 2027 specimen paper asks for the same word in a fill-in-the-blank. In 2025, CISCE's report also records "ovum" or "follicle" where "graafian follicle" was asked. Learn the stages as a timeline: follicle, Graafian follicle, ovulation, corpus luteum. See why marks slip away on answers you know.

About the author

Deepti Sardana

Founder Member & Academic Lead

An IIT alumna (M.Sc., M.Phil.) with over 25 years in teaching, child psychology and learning assessment. As Academic Lead at EduBrahma, she leads the method TRUtesting uses to find where and why a child loses marks.

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