structures and function in living systems

There appear to be many structures that are similar because of the function they carry out and in their external appearance. However, these structures differ internally. Such structures are called analogous structures. For example, wings of bat and..

The nephron or uriniferous tubule is the functional unit of the kidney. A nephron consists of a twisted tubule closed at one end, open at the other with a network of associated blood vessels. Each kidney of man is formed of about one million nephron..

This structure is responsible for the function of a protein. This structure is composed of various amino acids held together by peptide bonds. Proteins may have 1 or more polypeptide chains. Each polypeptide in a protein has amino acids linked with each other in a spe..

Each cell whether in a unicellular form like Gleocapsa or multicellular form like Nostoc, has a definite cell wall. Most often it is surrounded by a thin or thick mucilagenous sheath. The inner layer of cell wall has a chemical composition similar to bacterial cell, made up of peptidoglycans. The c..

Arrangement of Electrons in an Atom (Bohr-Bury Scheme) - Electrons revolve around the nucleus in different energy levels or shells and each shell is associated with definite energy. The energy of the K shell is the least while those of L, M, N and O shells increases progressively. We also know that..

The nephron or uriniferous tubule is the functional unit of the kidney. A nephron consists of a twisted tubule closed at one end, open at the other with a network of associated blood vessels. Each kidney of man is formed of about one million nephrons. Each nephron has a length of about 3 ..

. Hence, such secondary constrictions are called as nucleolar organizers. fig. 19.3 Structure of Chromosomes The terminal end of a chromosome is called as telomere. It is functionally different from the rest of the chromosome. A chromatid may breakup into pieces and the pieces m..

It consists of a pair of lungs, a pair of bronchi and a trachea. The lungs contain numerous microscopic functional units called alveoli. These structures are involved in pulmonary respiration. In addition, there is buccal respiration, through the buccal cavity and cutaneous resp..

The functions performed by the circulatory system in all animals are, Transport of nutrients like glucose, amino acids, vitamins, mineral..

Functions of Circulatory System - The functions performed by the circulatory system in all animals are 1) Transport of nutrients like glucose, amino acids, vitamins, minerals 2) Transport of oxygen from the organs of respiration to the body cells. 3) Transpor..