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Scientific eukaryotic cells vs prokaryotic cells
DNA as an investigative tool
Dna in criminal investigations research paper
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Part A Prokaryotic and Eukaryotic Cells
Introduction
Prokaryotic and Eukaryotic cells are both found in living thing, they have similarities and differences. This will be discussed further on in the essay. Prokaryotic cells are found in organism like bacteria which are archaebacterial and eubacteria whereas, eukaryotic cell are found in animals and plants.
Prokaryotic cells
Bacteria are prokaryotes, opposing from eukaryotes in having no membrane-bound nucleus or double- membrane organelles. Bacteria are an ancient group of tiny cellular organism which can be a size from 0.1 to 10 µm; they have colonised the earth for more than 3500 million years (Kent, 2013). Most of all, they have an important role in the food chains of every ecosystem.
In common with animal and plant cells, a general bacteria cell (prokaryotic cell) has a cell surface membrane enclosing cytoplasm that contains enzymes, ribosomes, and food granules. The membrane is encircled by a cell wall, and this results to an enclosed in a capsule. However, a prokaryotic cell has a shortage of high level of organisation of a eukaryotic cell. It has no Golgi apparatus nor an endoplasmic reticulum. The flagella are simple because they have no complex assembly of microtubules.
Some prokaryotic cells process additional circular pieces of genetic material called plasmids within the cell. Respiration generally takes place on a mesosomes, an infolding of the cell surface membrane, but there are no mitochondria (Micheal, 2013).
Function on the organelles
Mesosomes- the infolding of the cell surface membrane its involved in aerobic respiration.
Flagellum- simple locomotion structure one or two may be present.
Pili- may be involved in reproduction.
Capsule- providing protectio...
... middle of paper ...
...st powerful form. It allows biological sample at the crime scene to be linked and connected strongly to the individual whom it belonged to (Jackson, 2011). However, forensic scientist sometimes has to work with poor quality tissue samples containing degraded DNA which may give only a few bands. Overall, this has been successful in many ways in forensic science.
Bibliography
Jackson, A., 2011. DNA Profiling . In: Forensic Science . Essex: Ashford Colour Press , p. 158.
Kent, M., 2013. Bacteria . In: Advanced Biology . s.l.:Oxford University Press , p. 366.
Kent, M., 2013. Prokaryotes . In: Advanced Biology. s.l.:Oxford University Press, p. 466.
M.Kent, n.d. DNA profiling. In: Advanced Biology . s.l.:s.n., p. 410.
Micheal, K., 2013. Advanced Biology. 2nd ed. s.l.:Oxford University Press.
Micheal, n.d. The Variety of living things . In: Advanced . s.l.:s.n., p. 467.
U.S. Department of Energy, Office of Science. (2009). DNA Forensics. Retrieved from Human Genome Project Information: http://www.ornl.gov/sci/techresources/Human_Genome/elsi/forensics.shtml
small sample in need of identification, Polymerase Chain Reactions are used to multiply the DNA
Bacteria can function and reproduce as single cells but often combine into multicellular colonies. Bacteria are also surrounded by a cell wall. Archaea differ from bacteria in their genetics and biochemistry. Their cell membranes are made with different material than bacteria.
The analysis of the samples should be used only to confirm or negate match between the sample taken from the crime scene fgand the sample taken from the suspect. That is, it should sdfremain as an identifgication tool only. There should be no further analysis of the DNA to suggest psychological characteristics that would make the suspect more likely to have cdfommitted the crime. This rule should apply also to samples taken from convicted dfdoffenders for a data vor dagta bank.
The repeat segments are cut out of the DNA strand by a restrictive enzyme that acts like scissors and the resulting fragments are sorted out by electrophoresis (Saferstein 391). However, there are some drawbacks using the RFLP method in the forensic science community. The RFLP technique requires a large amount of DNA and must be of high quality and cannot be degraded (Jones). Forensic scientists and the law enforcement community determined a need for a DNA profiling method that could be used on smaller DNA samples. Thus, the RFLP technique has been almost entirely replaced by Polymerase chain reaction.
Prokaryotic cells do not have a nucleus. The chromosomes which are found in prokaryotes are usually spread in the cytoplasm. In eukaryotic cells the chromosomes remain together inside the nucleus and there is a clear nuclear membrane that is surrounding the nucleus.
Once a crime has been committed the most important item to recover is any type of evidence left at the scene. If the suspect left any Deoxyribonucleic acid (DNA) at the crime scene, he could then be linked to the crime and eventually charged. A suspect’s DNA can be recovered if the suspect leaves a sample of his or her DNA at the crime scene. However, this method was not always used to track down a suspect. Not too long ago, detectives used to use bite marks, blood stain detection, blood grouping as the primary tool to identify a suspect. DNA can be left or collected from the hair, saliva, blood, mucus, semen, urine, fecal matter, and even the bones. DNA analysis has been the most recent technique employed by the forensic science community to identify a suspect or victim since the use of fingerprinting. Moreover, since the introduction of this new technique it has been a la...
DNA testing is one of forensic sciences core techniques. Everyone has there own individual DNA profile, even identical twins. DNA is in every cell of our body. In the 1980s, a British scientist named Sir Alec Jeffery's, developed DNA profiling. Our DNA can be separated from human cells found at a Crime Scene, with perspiration, blood, skin, the roots of hair, semen, mucus, and saliva. The Colin Pitchfork case was the first murder conviction established on DNA profiling evidence.
Forensic Scientists can extract semen from a rape victim and use it to help identify the criminal. The semen extracted contains traces of DNA. Deoxyribonucleic acid, also known as DNA, is “the hereditary material in humans and almost all other organisms” (“What is DNA?”). Similar to fingerprints, no two persons have identical DNA with the exception of identical twins. The FBI began using DNA testing in criminal investigations in 1998 (Hays). In 1994, Congress authorized the Combined DNA Index System, also known as CODIS (Hays). This is a system of DNA records from national, state, and local crime labs (Hays). It contains more than four million DNA samples from convicted offenders, and more than 160,000 samples from crime scene evidence (Hays)...
Bacterial cells, like plant cells, are surrounded by a cell wall. However, bacterial cell walls are made up of polysaccharide chains linked to amino acids, while plant cell walls are made up of cellulose, which contains no amino acids. Many bacteria secrete a slimy capsule around the outside of the cell wall. The capsule provides additional protection for the cell. Many of the bacteria that cause diseases in animals are surrounded by a capsule. The capsule prevents the white blood cells and antibodies from destroying the invading bacterium. Inside the capsule and the cell wall is the cell membrane. In aerobic bacteria, the reactions of cellular respiration take place on fingerlike infoldings of the cell membrane. Ribosomes are scattered throughout the cytoplasm, and the DNA is generally found in the center of the cell. Many bacilli and spirilla have flagella, which are used for locomotion in water. A few types of bacteria that lack flagella move by gliding on a surface. However, the mechanism of this gliding motion is unknown. Most bacteria are aerobic, they require free oxygen to carry on cellular respiration. Some bacteria, called facultatibe anaerobes can live in either the presence or absence of free oxygen. They obtain energy either by aerobic respiration when oxygen is present or by fermentation when oxygen is absent. Still other bacteria cannot live in the presence of oxygen. These are called obligate anaerobes. Such bacteria obtain energy only fermentation. Through fermentation, different groups of bacteria produce a wide variety of organic compounds. Besides ethyl alcohol and lactic acid, bacterial fermentation can produce acetic acid, acetone, butyl alcohol, glycol, butyric acid, propionic acid, and methane, the main component of natural gas. Most bacteria are heterotrophic bacteria are either saprophytes or parasites. Saprophytes feed on the remains of dead plants and animals, and ordinarily do not cause disease. They release digestive enzymes onto the organic matter. The enzymes breakdown the large food molecules into smaller molecules, which are absorbed by the bacterial cells. Parasites live on or in living organisms, and may cause disease. A few types of bacteria are Autotrophic, they can synthesize the organic nutrients they require from inorganic substances. Autotrophic bacteria are either photosynthetic or Chemosynthetic. The photosynthetic bacteria contain chlorophyll that are different from the plant chlorophyll. In bacterial photosynthesis, hydrogen is obtained by the splitting of compounds other than water.
The term “microbiology” refers to the branch of study that deals with microorganisms. Microbiology is extremely important in today’s time for the crucial information that the study provides. Human’s have had a long and cruel history of disease and sickness, for example the bubonic plague, but microbiology gives scientists the ability to observe, study, and prevent sickness like the bubonic plague to ever happen again. At the center of microbiology lies the bacterial cell, one that differs from those of a plant or animal because it lacks a nucleus and membrane-bound organelles which, in turn are traded for pili, flagella, and in some cases a cell capsule. Bacteria that are capable of causing illness or disease are called pathogens, pathogens work by releasing toxins in the body or directly damaging the host’s cells. An article by Lise Wilkinson explains that the earliest categorizations of bacterial cells first occurred in the late eighteen-hundreds to the early nineteen-hundreds by scientists (at the time) O. Muller and C. Ehrenburg (Wilkinson, 2004). The observation and identification of unknown bacteria that emerge is crucial because these new bacteria might be pathogenic and cause illness so it is very important that the bacteria is identified as soon as possible in order to either prevent the upcoming illness or treat it. While the common person is unable to identify if they are carrying bacteria (which is very likely), specialized tests that are ran in a lab can identify different types of bacteria and can even help
of the book. New York: Oxford UP, 2011. 821-22. The. Print.