Oestrogen is a female sex hormone produced by the ovaries, which promotes the development of secondary sexual characteristics in girls and prepares the uterus for pregnancy. Oestrogen helps to control the menstrual cycle and it is important for childbearing. Oestrogen also has other functions like Keeping cholesterol in control and Protects bone health for both the sexes.

Hormones are chemical messengers of the body that transfers information from one set of cells to another. Each hormone has a definite function and acts on a particular tissue. Hormones are secreted from endocrine glands. These glands are known as ductless glands which pour their secretion directly into the bloodstream. Thyroxine, adrenaline, insulin, etc., are examples of some important hormones.

Insulin is a hormone that is secreted from the pancreas which regulates the blood sugar level in the body. Hyposecretion of insulin causes diabetes mellitus. It also regulates the metabolism of carbohydrates, fats and macromolecule by promoting the absorption of glucose from the blood into liver, fat and muscle cells.

This is Chintu's family. Chintu can be seen here with his father, mother and sister. Look at the picture carefully and answer the questions. Name the sex chromosomes present in Chintu's mother and father respectively. Explain why they are so called.

The sex chromosomes which are present in Chintu's mother and father are XX and XY respectively because Chintu's mother being a female has two X chromosomes in their cells, while father being a male has both X and Y chromosomes. Chintu's father is heterogametic while the mother is homogametic.

This is Chintu's family. Chintu can be seen here with his father, mother and sister. Look at the picture carefully and answer the questions. If Chintu's father produced sperms containing only the X chromosome, how many brothers would he have?

From the picture, we can conclude that Chintu has one sister. If his father produced sperms containing only the X chromosome, Chintu would not have any brother because the birth of a boy will only take place when a sperm with the Y chromosome fertilizes the egg, as the egg contains two similar types of chromosomes.