PCR (polymerase chain reaction) is a relatively new advance (1980's) but it has a great impact in our lives. Specifically, in forensic science, PCR is useful in many sorts of crimes . Up until the PCR method, in order to identify a person forensic scientists would use fingerprints or some other ambiguous methods like teeth marks etc. But now, with PCR, we can compare the genetic material found on a crime scene and compare it with a suspect's genetic material, definitively concluding whether they are the same person or not. The way this works is that we collect a sample from the crime scene with DNA and then PCR amplifies the quantity of DNA in that sample. One of the apparent advantages of this method is that PCR works with even a very small sample, often not even a single cell is required. This makes crime scenes full of information. Hence, succinctly, PCR has helped modern forensic science in that:
1) its results are more definitve than traditional identification methods and subject to less ambiguity
2) it is relatively fast
3) new pieces of evidence can be of value (like some hair cells) and identify the crominal in cases that in older times would be impossible to solve.
Even the cell membrane is like the cell wall its flexible and lets certain things in and certain things out.
Answer:
➢ In a mercury thermometer, <u>a glass tube is filled with mercury</u> and a standard temperature scale is marked on the tube. With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale. Mercury thermometers can be used to determine body, liquid, and vapor temperature.
#CarryOnLearning
