Biology Questions

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.

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.

Fluoride deficiency is a disorder which may cause increased dental caries due to a lack of fluoride in the diet. Dental caries or tooth decay is the breakdown of dental tissues by the acidic products released by the "bacterial fermentation of dietary carbohydrates”

Sensation is the activation of the receptors by stimuli.

Bacteria divided and reproduce by Binary fission. In this process, the bacterium, which is a single cell, divides into two identical daughter cells. Binary fission begins when the DNA of the bacterium divides into two replicates.

The energy in most ecosystems comes from sun light.

Epithelial tissue is made of layers of cells that cover the surfaces of the body that come into contact with the exterior world, line internal cavities, and form glands.

The four types of tissue in the body are epithelial, connective, muscle, and nervous.