Biology Questions

Tuber is considered as a modified stem. These type of stems carry out special functions that are important for the plant to survive. Tubers serves as a food reserve and bearing buds wherein new plants can grow.

The building blocks of the nucleic acids are "Nucleotides".

Each nucleotide are composed of three parts. They are ::

1.Pentose sugar

2.Nitrogenous bases

3.Phosphoric acid.

Biological membranes are composed of phospholipids, Proteins and Carbohydrate groups attached to lipids and proteins.

The renal medulla is composed of tissue called Renal Pyramids.

The mammalian heartis called myogenic (myo = muscle, genie = originating from). It means the heart beat or the activities of the heart are auto regulated which originates from a muscle called nodal tissue.In the human heart,heartbeat originates and contraction is initiated by a special modified heart muscle known as sinoatrial node. It is located in the right atrium; while the QRS waves are the depolarisation of the ventricles, which initiates the ventricular contraction.The T-wave represents the repolarisation,that is, the return of the ventricles from excited tonormal state.Hepatic portal system is the unique vascular connection that exists between the digestive tract and liver. This vein carries blood from intestine to the liver.