Topic 6 Flashcards
(49 cards)
Indicating the Time of Death
- Can be used to tell how long someones been dead for
- Depends on situation eg in water = harder to tell
Extent of Decomposition
- First Couple Hours - first hours of death/upto couple days
- Rate increases if temperature is higher and more oxygen available
Why are Microorganisms involved in decomposition
- Work to break down Organic Matter by secreting enzymes
- Carbon Compounds are recycled
Body Temperature during Death
- Alive, heat = metabolic reactions
- Cools 2 degrees every hour after death
- Factors affect this such as clothing
Forensic Entomology
-Finding out type of insects/microorganisms on body
Stages of Succession after Death
-Type of bacteria indicates period of death
Degree of Muscle Contraction after Death
- Rigor Mortis - stiffening of muscles
- muscles need ATP - attach the myosin head from the actin after contraction
- Anaerobic Respiration, lactic acid, glucose used up
Common Features in Euk and Pro Cells
- Plasma Membrane
- Cytoplasm
- DNA
- Ribosomes
DNA in Prokaryotes (Non-Living)
- Circular molecule in Cytoplasm
- Some smaller loops = Plasmids
- Bacteria - Plasmid Exchange
- eg Immunity Spread
Capsule Function
-Enable Prokaryotes to attach surfaces
Flagella Function
-tail like used for locomotion - in some pro.
Pili Function
-used to exchange genetic material during conjugation (type of reproduction)
Fimbriae Function
Used to attach host cell
Virus Structure
- nucleic acids
- Surrounded by protein called capsid
- Smaller then bacteria
What is DNA Profiling and when is it used
- Technique used for analysing samples of DNA
- Specific DNA patterns used to identify people, family, diseases etc
- Can be used in Crime Scenes
How do Scientists do DNA Profiling
-Order up all the Nucleotides, then compare to the existing DNA
Polymorphisms?
- Part of genomes that vary greatly
- used to distinguish between individuals and groups
Why is Polymerase Chain Reaction Used
-Increase DNA sample size
Polymerase Chain Reaction Steps (PCR)
- DNA heated to 96C = denatured strands to make them single
- Cooled to 60C to allow primers to anneal strands of DNA
- Heated to 72C so Taq Polymerase can work at optimum conditions = Extends nucleotide chains
- Repeated 25-35 times
What is a Primer
short lengths of DNA which free nucleotides can attach too
Why is Gel Electropheresis used?
-Separates DNA fragments according to size (number of base pairs)
Gel Electropheresis Steps
- DNA loaded into wells full of agarose gel
- Electric current passed through
- Negative charged DNA moves through to + electrode
- Smaller fragments move faster
- DNA ends up arranged in bands - similar strands together
Examples of Obtained DNA
-Hair, Skin, Saliva (Contains body cells)
How is DNA extracted from cells
- Nucleus extraced and isolated from cellular matter
- Using Detegents
