Biology (Part-V) (Railway)

• It attacks cells that help the body fight infection, making a person more vulnerable to other infections and diseases.

• If HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome).

• The entry of water into the stomata makes guard cells swell which leads to the opening of the stomata.

• The stomata close when the guard cells lose water and constrict, becoming flaccid and straight.

• In these reptiles, the temperature of the eggs during a certain period of development is the deciding factor in determining sex.

• Often, eggs incubated at low temperatures (22-27°C) produce one sex, whereas eggs incubated at higher temperatures (30°C and above) produce the other.

• Platelets (a type of blood cell) and proteins in our plasma (the liquid part of blood) work together to stop the bleeding by forming a clot over the injury.

• When platelets get to the site of the injury, they grow sticky tentacles that help them stick (adhere) to one another.

• Platelets are made in our bone marrow along with white and red blood cells.

• Some plants store waste material in the leaves which fall off, while some store it in the form of resins and gums.

• Medulla oblongata, also called the medulla, is the lowest part of the brain and the lowest portion of the brainstem.

• It is the study of genes, genetic variation, and heredity in organisms.

• It is an important branch in biology because heredity is vital to organisms' evolution.

• Gregor Mendel is knoun as father of genetics.

• The pressure exerted by blood against its walls of an artery during ventricular contraction is systolic pressure.

• It is estimated as 120mm Hg.

• In plants, the movements are usually at the cellular level and most of the plant cells are dead.

• Hence, a far less amount of energy is required by plants.

• Puberty is associated with emotional and hormonal changes, as well as physical changes.

• It is marked by voice changes, menstruation (in females), and noticeable physical changes such as breast enlargement, pimples widened hips, and growth spurts.

• Obesity is not a part of pubertal development.

• Obesity defined as excessive fat accumulatuin that may impair health.

• The funadamental cause of obesity is an energy ecbalance bitween calories consumed and calories expended.