1. What is a healthy organism?1.1. Discuss the difficulties in defining the terms ''health'' and ''disease''.
Health: A state of complete physical, mental and social health, and not merely the absence of disease or infirmity.
Health is difficult to define as health as many components such as physical, mental and social, some of which are very subjective.
Disease: A state of impared functioning of an organism, including impaired physical, mental and social functioning.
Disease is difficult to define as it also has many components. It depends on an organisms normal level of functioning and what they expect their quality of life to be.
1.2. Outline how the function of genes, mitosis, cell differentiation and specialisation assist in the maintenance of health.
Genes control the production of proteins needed for proper functioning of the body. Healthy genes ensure the correct proteins are made.
Through the production of proteins (e.g. enzymes), genes ensure that cell processes occur, maintaining metabolism and homeostasis.
Mitosis is the process that enables genetic material to be copied exactly, ensuring the genes are correct and able to maintain health.
Mitosis is also the process that organisms use to grow, maintain and repair body cells.
Cell differentiation and specialisation result in cells which are specialised for specific functions in the body, such as red blood cells.
Together they work in coordination to maintain the health and proper functioning of the organism.
1.3 Use available evidence to analyse the links between gene expression and maintenance and repair of body tissues.A healthy organism is the result of:
The correct functioning of genes.
The production of perfect copies of genetic material through mitosis.
The expression of genes in cell specialisation and differentiation.
The body's cells are constantly being replaced, the correct specialised cells must be produced to replace them. This is done through mitosis, followed by gene expression. Healthy cells have their cycle regulated by proteins that are produced by different types of genes. DNA repair genes ensure that DNA is accurately coppied. Two balanced genes that regulate the cell are:Proto-oncogenes: These produce proteins that stimulate division. Mutated proto-oncogenes are called encogenes and cause uncontrolled cell division (cancers).Tumor supressor genes: These produce proteins that stop division. Mutated tumor supressor genes lose their ability to control the rate of cell division, leading to uncontrolled growth (also cancer).
2. Over 3000 years ago the Chinese and Hebrws were advocating cleanliness in food, water and personal hygiene.2.1. Distinguish between infectious and non-infectious disease.infectious disease is an invasion of the body by an infectious agent that causes disease (pathogen). This disease can be transmited between organisms. Pathogens can be microscopic and microscopic. E.g. viruses (influenza), bacteria (tonsillitis), protozoans (malaria), prios (CJD), fungi (tinea).Non-infectious disease involves no pathogens. There is no transmission between organisms. E.g. Inherited disease (Down's Syndrome, haemophilia), nutritional disease (scurvy, beriberi), environmental (skin cancer, asbestosis).
2.2. Explain why cleanliness in food, water and personal hygiene practices assist in control of disease.Cleanliness of food:Contaminated food is a source of pathogens such as salmonella and can readily spread disease.Microbes in food only become a risk when they are allowed to multiply and reach large numbers.Modern methods to reduce the number of microbes in food and control the spread of disease include:- Heating: High temperatures kill microbes e.g. cooking food, pasteurisation- Cooling: Refrigeration slows down the growth of microbes.- Drying: Dehydrating food kills microbes, making them last longer.