Topic 6 - Infection + Forensics 🦠🤧

flashcards covering the whole of topic 6

Define AUTOLYSIS

the process in which cells or tissues are digested by their own enzymes.

Define: RIGOR MORTIS

Involuntary muscle contraction that occurs after death.

Why does body temperature decrease when you die?

Death results in decreased chemical reactions leading to a decline in body temperature.

Until how long is body temperature useful in determining time of death?

24 hours after death.

What are the factors that affect the rate of cooling?

body fat

body position

ventilation

humidity

clothing

What happens in the body when bacteria multiply and begin releasing gas?

Bloating

What is the term for when the skin turns a greenish color?

Putrefaction

What happens to the body 36 hours after death?

After 36 hours, the body becomes floppy again because enzymes have started breaking down muscle proteins.

What happens to the body 3-8 hours after death in terms of muscle rigidity and why?

The body becomes stiff and rigid approximately 3-8 hours after death.

This occurs because, without oxygen, aerobic respiration cannot take place = limited ATP production.

As a result, the muscles are unable to break the cross bridges between them.

What is forensic entomology?

Forensic entomology is the application of the study of insects and anthropods in the investigation of crime.

Why do fishermen put their maggots in the fridge?

To slow down the rate of development, because temperature affects enzyme activity.

Lower temperatures result in less kinetic energy, which means fewer enzyme-substrate complexes are formed.

As a result, metabolic processes slow down, causing the maggots to grow at a slower pace.

What is the reason for the succession of insects on a corpse?

Succession occurs because as the previous species consume and use the corpse as they please, they end up changing the conditions, making it suitable for the arrival of the next species.

In PCR what must you mix together before placing in a Thermocycler?

Your DNA sample, DNA primers, TAQ polymerase & DNA nucleotides.

What occurs at 95ºC in PCR?

The DNA denatures due to hydrogen bonds being broken, therefore becoming single-stranded.

What occurs at 55ºC in PCR?

DNA primers anneal to their complementary DNA sequence

What occurs at 72ºC in PCR?

DNA polymerase catalyses the binding of DNA nucleotides to the DNA via complementary base pairing .

Describe the structure of a virus

• contain linear genetic material.

• contain Viral enzymes.

• inner materials are surrounded by capsid.

• NO CYTOPLASM

Describe the additional structures of a complex virus

• The virus is surrounded by matrix protein.

• The matrix protein gets surrounded by an envolpe created from the cell membrane of the host cell.

• They have attachment proteins on their surface.

What are the 4 main ways the non-specific immune system responds to infection?

1. Inflammation

2. Releasing digestive lysozyme enzymes

3. Producing interferon

4. Phagocytosis

What does Histamine tell the body to do?

• Causes the dilation of Arterioles

• Increases blood flow & permeability of the capillaries causing them to leak plasma fluid, WBC & antibodies.

How are antigen-presenting cells produced?

They are produced when Macrophages engulf a pathogen, and then display the pathogen’s antigen on its surface.

What is the role of APCs?

To enhance recognition by T-Helper cells, which can’t directly recognise the antigen in blood fluid.

What is Clonal expansion?

When T & B cells undergo rapid mitosis, producing many many clones.