1.What is a healthy organism?
Discuss the difficulties in defining the terms ‘health’ and ‘disease’ * Health – state of physical, mental and social wellbeing. It is not just absence of disease * disease – any condition which effects the functioning of any part of a living organism * difficulties in defining health and disease; * health 1) the definition of health varies with age eg stiffness in the joints is probably more common in a 90yo than for a 20yo 2) it is possible for a person to have a disease but be healthy at the same time eg arthritis 3) health varies on a daily basis: some days we are full of energy and on others we feel lethargic * disease 4) the definition is very broad eg even minor ailments such as a cut finger using this definition would be regarded as a disease
Functioning of genes, mitosis, differentiation and cell specialisation are important in the maintenance of health * Genes = the units of inheritance. A gene is a small section of a DNA molecule that controls the production of a polypeptide or protein. Genes control the cell cycle, production of enzymes and production of other proteins including structural proteins and hormones. If a particular gene is not functioning correctly, the correct protein will not be made and body function will be impaired * Mitosis = type of cell division that produces new body cells. Mitosis allows for growth, repair and maintenance. If the genes that regulate the process of mitosis are permanently switched on then cancer will result. * Cell differentiation = the process where cells produced by mitosis became sorted out to form a certain cell type. Cells produced by a cancer tumour do not differentiate * Cell specialisation = the body contains many different types of cells white, red blood, bone, skin – these specialised cells are produced by cell differentiation. There are unique body cells
Links: Pasteur (1822-1859) French * Linked a number of infectious diseases to being caused by bacteria * Developed several different vaccines against diseases caused by bacteria or viruses eg Anthrax (bacterial), rabies (viral) Koch (1843-1910) German