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Topic 6
INFECTION, IMMUNITY AND INFECTION

Fingerprint methods are used to identify a dead body with no identification papers on them.
Fingerprints are small ridges caused by folds in the epidermis of the skin. Sweat and oil leave
impressions on surfaces we touch. Oils are secreted from sebaceous glands (non…

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The first separates the double stranded DNA. The second temperature optimises prime
binding to the target DNA sequence in the sample. The polymerase attaches and replication
occurs. The final temperature is the optimum temperature for the heat stable DNA
polymerase.

DNA fragments can be separated by gel electrophoresis according to…

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fluorescent it is viewed using UV light.




The STR is inherited like genes so are used for identification purposes.

Determining Time of Death
The temperature of the body, the degree of rigor mortis and the state of decomposition
can be used to estimate time of death. In addition, entomological (insect)…

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person dies the body cools down due to no heat producing reactions taking place.
Temperature is measured through the rectum or an abdominal stab wound, with a long
thermometer (normal ones are too short and have a lower temperature range).
However, environmental conditions must be noted as they can change…

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For the commonest bluebottle species found on bodies, Calliphora Vicina, a graph is
seen to determine age. (only used if temperature conditions have stayed constant).
Fly lifecycle... egg: 1 day. Lava: 9 days. Pupa: 612 days.
Other factors e.g. toxins in the body will affect the results ­ cocaine would…

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the cell surface or burst out of the cell splitting it open. This splitting kills the cell and is
called lysis.








Transmission of TB bacterium
It is carried in the droplets of mucus and saliva released into the air when an infected
person talks, coughs or sneezes. This is known…

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chemicals such as histamines, causing the arterioles to dilate, increasing blood flow to
the area. Plasma fluid, white blood cells and antibodies leak from the blood causing
oedema (swelling) ­ the microbes can now be attacked by intact white blood cells.
Phagocytosis
Phagocytes are white blood cells that engulf bacteria…

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Interferon provides nonspecific defence against viruses.
Lymphocytes are white blood cells that help to defend the body against specific
diseases. They circulate in the blood and lymph and gather at the site of infection.
B and T cells (Lymphocytes)
This is the specific immune response.
B cells = secrete antibodies…

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(release antibodies into the blood and lymph).
B memory cells ­ long lives, enable body to respond more quickly to the same antigen
in the future.
The process of B cell division is called Clonal Selection. It takes about 1017 days to
produce sufficient antibodies called the primary immune response.…

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infection may break out if the immune system isn't working properly.
Activity of immune system is reduced in old and very young ages, also by malnutrition
and poor living conditions.
Most significant factor is AIDS. HIV the virus that causes AIDS directly targets white
blood cells and reduces patient's ability…

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