9.4 The search for better health

* Outline how the function of genes, mitosis, cell differentiation and specialisation assist in the maintenance of health:
- The function of genes; To ensure that the correct proteins are produced in a cell to enable all cellular processes to continue.
If genes are faulty, and the polypeptides and proteins they make are also faulty, then the cell processes or structure may be abnormal and can lead to disease.

The functioning of cell differentiation and specialisation;CELL DIFFERENTIATION AND SPECIALISATION:
Cell differentiation is when cells mature and take on different structural features so that they're structurally suited to perform a specific function in the body. E.g. RBC's contain HB to transport oxygen around the body.
- Cell specialization is when specific genes in cells are switched 'on' or 'off' in order to perform a specific function in the body. E.g. in RBC's, the gene for HB is switched on, allowing the RBC to perform its specific function of oxygen transport.

If differentiation and specialization didn't occur, processes in the body wouldn't be coordinated as the cells wouldn't be able to function effectively.

* Distinguish between infectious ad non-* Distinguish between infectious ad non- disease:
Infectious diseases are caused by a pathogen that enters the body and can be transferred from person to person.
-A Non-infectious disease is not caused by a pathogen or organism carrying disease.
- These diseases are caused instead from genetic, lifestyle or the environment.

*Explain why cleanliness in food, water and personal hygiene practises assist in control of disease:
-As infectious diseases are caused by pathogens, controlling disease should focus on preventing pathogens from entering the body. This involves reducing exposure to pathogens, preventing pathogens from multiplying in food, water or the body, and preventing transmission of the pathogen between people.

* Gather, process and analyse information from secondary sources to describe ways in which drinking water can be treated and use available evidence to explain how these methods reduce the risk of infection from pathogens:
-Coagulation - Coagulants are added to the water and cause the binding together of fine particles such as clay and silt. It reduces the risk of infection because Microbes become trapped in the particles.
Filtration is The passage of water through a bed of fine particles e.g. sand. It reduces the risk of infection as it Removes fine, suspended solids that contain microbes and larger microorganisms.

Robert Koch:
Studied the cause of the disease anthrax. -He succeeded in isolating the bacterium from the blood of the dying animals.
- He found out that the blood of animals with the disease always contained the micro-organisms and also that if it were injected into a healthy animal it would also cause the disease.

* Distinguish between -
Prions: Are infectious agents that cause brain disease in mammals.
-They are proteins that have been altered from their normal shape.
-characteristics include; dementia, loss of motor control.
-In animals; Mad cow in cattle.
-Viruses:
-Found in all types of cells
- Only reproduce inside another cell, called a host cell.
- Once inside the nuclear material from the virus causes the cytoplasm of the host cell to produce new viruses.
E.g Small pox, measles, warts, influenza.

*Explain why cleanliness in food and water and personal hygiene practises assist in the control of disease:

* Identify the role of antibiotics in the management of infectious disease:

* One named infectious disease: -MALARIA:
- Caused by the protozoan parasites of the genus plasmodium
- Transmitted by the female mosquito
- The malarial parasite was first identified in the stomach of an anopheles mosquito by Ronald Ross. - The life cycle of the malarial parasite: 1) The infection is a result of a bite from a female mosquito that is carrying the parasite. 2) When the female mosquito pushes its feeding tube through the human skin, it injects its saliva which contains a anticoagulant(stops the blood from clotting) so the mosquito can keep consuming the blood. 3) If the mosquito is infected the parasites are released into the human blood stream.

- MUCOUS MEMBRANES:
- Line the digestive, respiratory, reproductive and urinary tracts with a thick mucus.
-It allows for the change of substances whilst also protecting against invasion.
- The presence of IGA Antibodies in mucus reacts with the pathogens preventing their invasion.
-CILIA:
-Are minute hairs that project from the cells lining the respiratory surfaces of the nose, trachea and bronchial tubes.
- The cilia sweep the mucus along so that any particles breathed in and trapped in the mucus can be transported out.

*Identify antigens as molecules that trigger an immune response:
- The body's immune response is it's reaction to invasion of foreign materials. These substances are identified as foreign by the body which then responds by trying to destroy them. Substances that trigger this reaction are known as antigens.

* Identify defence adaptations, including;
1) Inflammation response-
When any body tissue is damaged, the are becomes red, hot, swollen and painful. The blood circulation to that part is increased and the blood vessels dilate. This helps confine the pathogen while white blood cells attack it and destroy it.
2) Phagocytosis:- Are white blood cells that can actively move from the blood tissues, where they ingest and destroy an foreign materials. - Phagocyte is called Neutrophils= During acute inflammation (Lasting hours our days) - Phagocyte is called macrophages= During chronic inflammation( Weeks or months)

Cell death to seal of pathogens:
- When the body is unable to neutralise an antigen, a particular type of chronic inflammation involving both macrophages and lymphocytes may occur.

*Identify the components of the immune response:
1) Antibodies (immunoglobins) : Are proteins that the body produces when it detects specific antigens.
Different antigens stimulate the production of different antibodies.
Join with antigens, causing them to clump together to form an antibody-antigen complex.

B-cells: (Plasma cells)
- Control the blood response where they are activated when antigens enter the blood stream.
- Once activated they clone themselves and then differentiate into the plasma cells that send antibodies into the blood or into memory cells.

- Edward jenner hypothesised that milkmaids hardly got the disease and that their prior infection with the relatively harmless disease known as 'cowpox' may have protected them.
-Using similar techniques to Jenner, researchers devised an effective small pox vaccine based on the 'vaccina virus'.
- Within 12 years smallpox was eradicated.

- The range of T lymphocyte types and the difference in their roles:
- Cytotoxic T cells produce toxic substances that destroy cells that have been invaded by a pathogen.
- Helper T cells help B cells divide rapidly.
- Suppressor T cells turn off the immune response and suppress the production of antibodies when they are not needed.
- Memory T cells recognise the antigen if it is re-introduced, providing long-term immunity.

*Outline the reasons for the suppression of the immune response in organ transplant patients:
- Is necessary to prevent rejection of new organs.
- Because the blood drains from transplanted organs into the patients circulation the body recognises it as foreign tissue and produces antibodies in response.
- Rejection is stopped by matching the transplanted tissues proteins to the recipients proteins as closely as possible.