The Search For Better Health 1 Flashcards
Discuss the difficulties in defining “health” and “disease”.
According to the World Health Organisation (WHO), heath is “a state of complete physical, mental and social wellbeing, and not merely the absence of disease or infirmity”; and disease is “any condition that adversely affects the normal functioning of any part of a living being.”
These definitions cannot be taken literally as the definitions of health and disease are very broad and subjective from individual to individual.
No one person can be completely healthy physically, mentally and socially at the same time. Similarly, healthy for a patient with a chronic disease or disability may mean their ability to adapt their lifestyle to their condition.
A broken bone or pregnancy can “adversely affect normal functioning” but they aren’t diseases at all!
“Normal functioning” is also subjective. The degradation of the mind may be accepted as a part of ageing, but that same condition may be called a disease in a young person.
Use available evidence to analyse links between gene expression and the maintenance and repair of body tissues.
Genes are responsible for the coding and synthesis of proteins.
Proteins are responsible for the growth, repair and maintenance of cells, and therefore body tissues.
A gene’s expression is evident in the kind of protein it produces and what effect that protein has on the body.
If a mutation occurred in a gene, it wouldn’t be able to produce the correct protein.
Proper maintenance/growth/repair of body tissues cannot occur because the protein responsible for it cannot be produced.
e.g. The BRCA 1 gene codes for proteins which repair the PTEN gene. The PTEN gene is responsible for the synthesis of proteins which control cell division and encourage cell death.
Both of these genes are tumour suppressor genes.
A mutation the in BRCA 1 gene would mean it cannot produce a protein to repair the PTEN gene. If the PTEN gene is damaged, it cannot be repaired and thus cannot synthesize the protein that maintains normal cell cycle. Cell division would not be maintained with the absence of this protein, resulting in a tumour or cancer as cell death isn’t encouraged either.
Outline how the function of genes, mitosis, cell differentiation and specialisation assist in the maintenance of health.
Genes code for proteins.
Proteins are responsible for normal cell functioning, growth and repair (includes mitosis).
Mitosis allows the body to repair or grow.
If a mutation occurs in a gene, it wouldn’t be able to synthesize the correct protein. Without this protein being produced, the function it carries out can’t be made. This function may be the maintenance, repair and/or growth of cells.
There are three types of genes which are responsible for cell cycle regulation and mitosis:
- DNA repair genes: codes for proteins which stop a cell cycle and allow for other proteins to remove and replace damages DNA.
- Proto-oncogenes: codes for proteins which code for cell growth and mitosis. Oncogenes are created when a mutation occurs in the proto-oncogene, causing unhindered cell production and preventing cell death.
- Tumour suppressor genes: codes for proteins which slow or stop cell growth and mitosis, also triggers cell death.
Uncontrolled cell death may also be caused by mutations e.g. Alzheimer’s disease.
Cell differentiation is where a cell matures and develops to be structurally different in order to carry out a specific function e.g. stem cells to nerve cells.
Specialisation is where genes are “switched on and off” when they are needed to perform a particular body function.
Cell differentiation and specialisation allow the body to carry out complex functions in a coordinated effort. Without the proper working of either of these two processes, bodily functionality would decrease.
