Imm, Infec, Forensics

• What can be determined by examining the extent of decomposition in a mammal?

  Time of death
• How does decomposition begin in a mammal's body?

  Enzymes from the digestive system break down tissues
• Why is the stage of decomposition useful in determining time of death?

  It indicates how long a body has been dead
• What is forensic entomology?

  Study of insects to determine time of death
• How can the age of insects help in forensic investigations?

  It helps determine the time of death
• What does the change in species colonizing a body indicate?

  It can indicate the time of death
• What happens to body temperature after death?

  It begins to decrease
• Why is body temperature only useful for determining time of death within the first 24 hours?

  Body temperature equalizes with surroundings
• What factors affect the rate of body temperature decrease after death?

  Body size, covering, and weather conditions
• What is rigor mortis?

  Stiffening of muscles after death
• What causes rigor mortis to occur?

  ATP depletion and calcium ion buildup
• How long does rigor mortis last after death?

  About 36 hours
• What role do microorganisms play in decomposition?

  They decompose organic matter and recycle carbon
• What are introns in DNA?

  Non-coding regions of DNA
• What are exons in DNA?

  Coding regions of DNA
• What contributes to genetic variability between organisms?

  Introns and exons in DNA
• What are short-tandem repeats?

  Repeating base sequences in introns
• What is the purpose of Polymerase Chain Reaction (PCR)?

  To amplify DNA samples for analysis
• What components are mixed in the PCR reaction mixture?

  DNA sample, primers, nucleotides, DNA polymerase
• At what temperature are the DNA strands separated in PCR?

  95 degrees Celsius
• Why is the temperature lowered to 50-65 degrees in PCR?

  To allow primers to bind to DNA strands
• What happens at 70 degrees during PCR?

  DNA polymerase synthesizes new DNA strands
• What is gel electrophoresis used for?

  To separate and visualize DNA fragments
• How are DNA fragments prepared for gel electrophoresis?

  They are cut with restriction endonuclease enzymes
• What happens to DNA in gel electrophoresis?

  It moves towards the anode due to negative charge
• What are mini/microsatellites in DNA?

  Repeated sequences in introns
• How does the similarity of repeats relate to genetic relationships?

  More similar repeats indicate closer relationships
• What is the structure of a virus?

  Nucleic acid enclosed in a protein coat
• Why are viruses not classified as living organisms?

  They require a host to survive
• How do bacteria differ from viruses in structure?

  Bacteria have cell membranes and organelles
• What is tuberculosis caused by?

  Mycobacterium tuberculosis
• What happens to infected phagocytes in tuberculosis?

  They are sealed in tubercles in the lungs
• What occurs when the immune system weakens in tuberculosis?

  Bacteria become active and destroy lung tissue
• What is the first symptom of HIV infection?

  Flu-like symptoms
• What indicates a person is HIV positive?

  Presence of HIV antibodies in blood
• What happens after the initial symptoms of HIV infection?

  Symptoms disappear until immune system weakens
• What are some symptoms of AIDS?

  Weight loss, diarrhoea, dementia, cancers
• How do physical barriers protect against infection?

  They prevent pathogens from entering the body
• What is the role of stomach acid in infection prevention?

  Kills bacteria
• How does inflammation help in response to infection?

  Increases blood flow and permeability to tissues