quarter 1 forensic final
True or False: The word forensic refers to the application of scientific knowledge to legal questions
False: forensic science refers to the application of scientific knowledge to legal questions
True or False: it is necessary to obtain a full print from a suspect in order to compare his fingerprint with a fingerprint found at the crime scene
False: it is not necessary to obtain a full print from a suspect in order to compare his fingerprint with a fingerprint found at the crime scene and most prints recovered from a crime scene are only partial prints. Identification of minutiae patterns can be done without having a full fingerprint
True or False: plastic prints must be dusted or treated in order to identify the ridge patterns
False: latent prints must be dusted or treated in order to identify the ridge patterns
A forensic scientists is called to a court of law to provide: a) facts b) opinion c) judgement d) reflection
a) facts
what is the compound light microscopy?
SERIES OF LENSES AND USES A VISIBLE LIGHT AS ITS SOURCE OF ILLUMINATION
What can the composition of microbiome in soil indicate?
Similarly, the composition of the microbiome present in a soil sample may prove a useful indicator of: 1. geographic origin 2. linking people, animals, or objects together 3. linking people, animals, or objects to a specific location
True or False: It is important to always photograph a fingerprint before you attempt to lift it
true
True or False: similar print or ridge patterns can also be found on the toes
true
What are the units of measurements?
use metric system to measure microorganisms: 1. micrometer (um) = 0.000001m (10⁻⁶ m) 2. nanometer (nm)= 0.000000001 (10⁻⁹ m) 3. eukaryotic cells = 100 um 4. mitochondria = 1um 5. viruses = 100nm 6. proteins and lipids = 10nm 7. atoms = 0.1 nm
what does a plain whorl on a fingerprint look like?
(plain whorl) a fingerprint pattern that resembles a bull's-eye
What was the golden age of microbiology?
1. 1857-1914 explosion of discoveries in micro: a) fermentation and pasteurization b) the germ theory of disease c) vaccination 2. FERMENTATION AND PASTEURIZATION: a) Why do wine and beer sour? b) microorganisms called yeasts convert the sugars to alcohol in the absence of air-FERMENTATION- in the presence of air bacteria change the alcohol in the beverage to vinegar c) heat beer and wine just enough to kill most of the bacteria that caused spoilage-PASTEURIZATION
what is a fingerprint?
1. A fingerprint is the impression made by the papillary ridges on the ends of the fingers and thumbs 2. The edge arrangement on every finger of every human being is unique and does not alter with growth or age 3. The practice of utilizing fingerprints as a means of identification, referred to as dactyloscopy, is an indispensable aid to modern law enforcement 4. Finger impressions are preferred to those from other parts of the body because they can be taken with a minimum of time and effort
outline the steps in taking a ridge count from a fingerprint
1. A ridge count distinguishes between the number of ridges between the core and the center of the delta and it may help distinguish one fingerprint from another. 2. To take a ridge count for a loop pattern, draw an imaginary line from the center of the core to the middle of the delta. 3. Then count the number of ridges between the core and the center of the delta.
What are biogenesis? Who is Louis Pasteur?
1. BIOGENESIS: LIFE COMES FROM PREEXISTING LIVING CELLS 2. 1858 spontaneous generation is still unresolved 3. Rudolf Virchow, a German scientists, challenged spontaneous generation 4. LOUIS PASTEUR- 1861, he demonstrated that microorganisms are present in the air and can contaminate sterile solutions, but air itself does not create microbes 5. Pasteur developed the S-shaped curved flask which trapped microbes in the neck 6. PASTEUR'S RESULTS: a) microorganisms can be present on nonliving matter- on solids, in liquids, and in the air b) microbial life can be destroyed by hat c) discoveries form the basis of ASEPTIC TECHNIQUES- prevent contamination of unwanted microorganisms and are standard practices in laboratory and medical procedures
what conditions are necessary for bacteria to grow?
1. Bacteria and other microorganisms can be found in nearly any moist environment that has the minimal required nutrients for life: a) an energy source b) basic elemental building blocks such as carbon, hydrogen, oxygen and nitrogen 2. Bacteria can be found in very common places such as on food or in unusual places such as hot volcanic springs
How do you test for reducing sugars?
1. Benedict's qualitative solution is a test reagent that reacts positively with reducing sugars 2. All monosaccharides and most disaccharides are reducing sugars-that is, they possess a free, or potentially free carbonyl group (C=O) that reacts to reduce Benedict's solution 3. A positive Benedict's test can be seen by the formation of a brownish-red cuprous oxide precipitate when heated 4. a negative test is shown if the Benedict's solution remains blue when heated
How do you test for proteins?
1. Biuret solution can be used to determine the presence of protein. 2. Biuret is used to test for protein in albumin 3. Biuret solution will turn to a pinkish or purplish color if protein is present
what is the difference between class and individual evidence?
1. CLASS EVIDENCE narrows an identity to a group of persons or things a) ex: blood type A+ 2. INDIVIDUAL EVIDENCE narrows an identity to a single person a) ex: DNA from type A+ blood b) main individual evidence is DNA or fingerprints as long as trace evidence is left
What are the common shapes and groupings of bacteria?
1. Common shapes of bacteria: a) Bacillus/bacilli- rod shaped b) Coccus/cocci-spherical, round c) spiralla/spirillum-cork screw, spiral shaped 2. Bacteria can be found in different groupings: a) singly- one single bacterium b) diplo- a pain of bacteria joined together c) strepto- a chair of bacteria d) staphylo- a cluster of bacteria
what are culture media?
1. Culture media: mixtures that contain solutions rich in nutrients and are made by microbiologists to encourage the rapid growth of bacteria and other microorganisms a) the nutrients in culture media provide necessary building blocks for bacteria to grow and reproduce very quickly 2. Culture media can be made in a semi-solid "Jello-like" stage (agar) or it can in liquid form (broth). 3. Bacteria are easy to grow a) when conditions are right they grow and reproduce very rapidly!
What are the modified compound microscopy
1. DARKFIELD MICROSCOPY: examine live material that are: a) invisible in the ordinary light microscope b) cannot be stained by standard microscope c) distorted by staining that their characteristics cannot be identified d) no direct background light, the specimen appears light against a black background 2. PHASE CONTRAST: permits detailed examinations of internal structures of living microorganisms a) no staining required b) direct and reflected light are brought together to form the image 3. DIFFERENTIAL INTERFERENCE CONTRAST MICROSCOPY (DIC) a) similar to phase-contrast microscopy b) uses two beams of light instead of one c) prisms split each light beam, adding contrast colors d) resolution is higher than phase-contrast e) image appears 3-D 4. FLORESCENCE: uses ultraviolet source of illumination a) for fluorescent-antibody technique to rapidly identify microbes in tissues or clinical specimens 5. CONFOCAL MICROSCOPY: uses tase light to illuminate one plane of a specimen at a time a) obtain cells two and three dimensional images of cells for biomedical applications b) most often used in conjunction with computers
what are the emerging infectious disease and give examples?
1. Diseases that are new or changing and are increasing or have the potential to increase 2. factors that have contributed to the emergence of these new microbes a) evolutionary changes b) spread to new geographic locations by modern transportation c) deforestation and construction 3. Examples: a) west nile b) mad cow- bovine spongiform encephalopathy c) CJD- Creutzfeldt-Jakob disease d) Ebola hemorrhagic fever d) AIDS
What is the principle of exchange?
1. Dr. Edmond Locard, director of the worlds first forensic lab in Lyon, France was the first person to note this condition 2. LOCARD'S EXCHANGE PRINCIPLE: when a person comes into contact with an object or another person, a cross-transfer of physical evidence can occur a) leave trace evidence and also take evidence with us in every situaiton
How do your fingerprint develop? Do injuries affect it?
1. Each ridge of the epidermis (outer skin) is dotted with sweat pores for its entire length 2. and is anchored to the dermis (inner skin) by a double row of piglike protuberances 3. Injuries such as superficial burns, abrasions, or cuts do not affect the ridge structure or alter the dermal papillae a) the original pattern is duplicated in any new skin that grows 4. An injury that destroys the dermal papillae, however, will permanently obliterate the ridges
What is the history of fingerprinting? What is Galton-Henry system of fingerprinting?
1. Early anatomists described the ridges of the fingers 2. Interest in modern fingerprint identification dates from 1880, when the British scientific journal Nature published letters by the Englishmen Henry Faulds and William Herschel describing the uniqueness and permanence of fingerprints 3. Their observations were experimentally verified by the English scientist Sir Francis Galton, who suggested the first elementary system for classifying fingerprints based on grouping the patterns into arches, loops, and whorls 4. Galton's system served as the basis for the fingerprint classification systems developed by Sir Edward R. Henry, who later became chief commissioner of the London metropolitan police 5. The Galton-Henry system of fingerprint classification, published in June 1900, was officially introduced at Scotland Yard in 1901 and quickly became the basis for its criminal-identification records 6. The system was adopted immediately by law enforcement agencies in the English speaking countries of the world and is not the most widely used method of fingerprint classification
Explain why eyewitnesses are (a) separated before providing their account of what happened and (b) asked to repeat their story several times
1. Eyewitnesses are separated before providing their account to avoid witnesses influencing each other's stories or sharing untruths 2. they are also asked to repeat their story several times to determine if they are telling the truth because it is easier to repeat something that is true but difficult to remember the lie they told a) if the eyewitness is telling the truth, the account of what happened is consistent each time they tell the story
What are the disease causing protists?
1. Giardia lamblia is contracted by animal feces through contaminated water a) symptoms include diarrhea and intestinal cramps 2. Entamoeba histolytica enters the body through contaminated water a) attacks the lining in the intestines
Who first observed microorganisms?
1. In 1665 Robert Hooke observed "tiny boxes" in a piece of cork and named them cells 2. His discoveries led to the cell theory: ALL LIVING THINGS ARE COMPOSED OF CELLS 3. Antoni Van Leeuwenkoek is the first person to observe live organisms called them "animalcules"
Discuss methods practiced by law enforcement that are used to obtain accurate eyewitness accounts
1. Law enforcement use several interviewing methods such as: a) separating eyewitnesses as soon as possible, b) interviewing one person at a time so that no one else influences their memory of what occurred, c) write down their observations during the interview or as soon as possible afterward, d) ask questions to draw out details during the interview. 2. They can also ask the interviewer: a) to repeat their story several times b) recount the story in reverse order or events c) ask the interviewee on or off topic questions to distract them all in an attempt to determine if they are telling the truth or not
What is the birth of modern chemotherapy? What are antibiotics and what was the first synthetic drug?
1. Medical microbiologists search for substances that could destroy pathogenic microbes without damaging the infected animal or human 2. treatment of disease by using chemical substances: CHEMOTHERAPY a) SYNTHETIC DRUGS (LAB MADE) b) ANTIBIOTICS (NATURALLY MADE) 3. 1910 Paul Ehrlich found a chemotherapeutic agent called SALVARSON, an arsenic derivative effective against syphilis a) by the 1930s, several synthetic drugs could destroy microbes 4. Alexander Fleming found culture plates that had been contaminated by mold a) around the mold was clear space where the bacteria growth was inhibited b) the mold was identified as PENICILLIUM NOTATUM 5. Some problems associated with antibiotics: a) many antimicrobial chemicals are too toxic to humans for practical use b) the emergence and spread of new varieties of microorganisms that are resistant to antibiotics c) Staphylococcus aureus and Enterococcus faecalis have recently become resistant to antibiotics which has alarmed health care professionals
what are microbes?
1. Microbes, also called microorganisms, are minute living things too small to be seen with the unaided eye 2. Ex: microscopic algae, protozoa, fungi, bacteria, viruses
how are microorganism important in the decay process and showing bodily processes?
1. Microorganisms are important in the decay process a) when an organism dies, bacteria will stay alive. When organisms bloats up and decays it is because microbes are still releasing gas b) pinpoint time of death by what microbes are doing, season, and setting c) bacteria have impact on decaying process so they can identify time of death 2. They also influence the presence and concentration of alcohol, drugs, and other chemicals of forensic relevance a) can show how long the drug has been in the system by bacteria's actions 3. there is also a possibility that the entry of microorganisms into the body during the atonal period may prove useful for the diagnoses of drowning
What is recombinant DNA technology?
1. Microorganisms can now be genetically engineered to manufacture large amounts of human proteins: a) desired gene is a human is identified and isolated b) gene is spliced into a bacteria plasmid c) recombinant DNA-DNA of two different organisms-is inserted back into the bacterium d) bacteria reproduces and makes a copy of the human gene
What are the new developments in microbiology?
1. New branches of microbiology have been developed a) immunology b) virology c) recombinant DNA technology 2. The study of bacteria-BACTERIOLOGY 3. the study of fungi-MYCOLOGY 4. The study of protozoa and parasitic worms- PARASITOLOGY 5. All three fields are going through a "GOLDEN AGE FO CLASSIFICATION" 6. Advances in GENOMICS-study of an organisms genes-have allowed scientists to classify bacteria and fungi
Another way to make prints visible is to apply certain chemicals. What component of a fingerprint chemically reacts with each of the following? a) Ninhydrin b) cyanoacrylate c) silver nitrate d) iodine fuming
1. Ninhydrin reacts with amino acids from proteins found in sweat to form a purplish blue latent print. 2. Cyanoacrylate reacts with amino acids, proteins, and fatty acids to form a white latent print. 3. Silver nitrate reacts with chlorine from salt in perspiration on the print and they combine to form silver chloride. 4. The latent print produced is a black or reddish-brown print under UV light. 5. Iodine fuming combines iodine with carbohydrates in latent print to form a latent print that is brownish in color and fades quickly. a) The latent print from iodine fuming must be photographed or sprayed with a starch solution in order to see the print for a longer period of time.
Is it possible alter fingerprints? Defend your opinion, citing evidence from the chapter.
1. No, it is not possible to alter fingerprints permanently because altered or damaged fingerprints will grow back after the alteration. 2. Sometimes, the scars that are formed by trying to remove fingerprints make fingerprint identification easier. 3. For example, pineapple juice contains an enzyme that digests protein including the protein fingerprint ridges in the skin. 4. These ridges are temporarily removed when exposed to pineapple juice and result in poor fingerprints. 5. Once a person ends their exposure to pineapple juice, his fingerprints will grow back. 6. Since the fingerprints will grow back despite alteration attempts, fingerprints can not be permanently altered.
how is on the crime scene investigation team?
1. Police officers: first responders who secure the scene 2. CSI: document the crime scene, photographs, collect evidence 3. Medical examiner: coroners, determine cause of death 4. detectives: look for leads, interviewing witnesses 5. specialists: entomologists, forensic psychologists, etc
what are the different types of stains?
1. STAINS are salts composed of positive and negative ions- one of which is color called CHROMOPHORE 2. the color of BASIC DYES is in the positive ion a) crystal violet b) methylene blue c) malachite green d) safranin 3. the color of ACIDIC DYES is in the negative ion a) not attracted to most bacteria b) color stains background instead of the specimen- NEGATIVE STAIN c) used in the observations of cell shapes, sizes, and capsules d) distortion of the cell is minimized because no heat is needed and the cells do not pick up the stain 4. bacteria are slightly negatively charged at pH 7, so the colored positive ions in a basic dye are attracted to the negatively charged bacteria cell
What was the debate over spontaneous generation?
1. Spontaneous Generation: life could arise from nonliving matter 2. ex: flies arise from manure, maggots could arise from decaying corpses 3. Francesco. Redi: 1668 tried to disprove spontaneous generations by placing netting over jaws with meat inside. The jars remained free of maggots which was a huge blow to spontaneous generation 4. Lazzaro Spallanzani: 1765 tried to disprove the "virtual force" that gave rise to microorganisms in the air by heating nutrient fluids after being sealed. It showed no microbial growth. a) skeptics argued that he killed the "vital force" necessary for spontaneous generation to occur, but not enough oxygen in the sealed flask to support microbial life
What is a starch and how do you test for it?
1. Starch is a complex carbohydrate and a primary source of energy in the food we eat 2. iodine is a good indicator for starch because it forms an adsorption complex with a characteristic royal blue or purple color when starch is present 3. The iodine remains a yellow/orange color when starch is not present
How do you test for fats?
1. Sudan III can be used to test various foods for the presence of fat 2. In the presence of fat, Sudan III will stain fats and oils pink from their original yellow/white color 3. Sudan III will not dissolve or disperse in the absence of a fat
what is the difference between trace evidence, direct evidence, and circumstantial evidence?
1. TRACE EVIDENCE: transferable materials include: a) hair b) fingerprints c) soil d) blood drop e) fiber f) footprints 2. DIRECT EVIDENCE: firsthand observations such as eyewitness accounts or police dashboard video cameras a) anything recorded on security cameras, eye witnesses, dashboard cameras b) details are jumbled in eyewitness testimony but always report the facts c) separate suspects so they can't talk to each other to persuade each other of certain events d) separate witnesses and focus on what everyone agrees on 3. CIRCUMSTANTIAL EVIDENCE: indirect evidence that can be used to imply a fact, but that does not directly prove it a) ex: suspect's gun at the site of a shooting is circumstantial evidence of the suspect's presence there because you can't prove that he is there without more evidence
how can microbial forensics indicate the transmission of diseases?
1. The transmission of infectious diseases, and in particular sexually-transmitted diseases, can provide evidence linking a victim and a suspect (through the bacteria) 2. microorganisms that cause fatal infections are not always identified at the time of death and may lead to the death being considered 'suspicious' a) is it malicious or accidental? (same with sexually transmitted disease) 3. if a fatal infection can be linked to a hospital or medical procedure it can lead to prosecutions and therefore it is important to determine when and where an infection was acquired 4. similarly, naturally acquired infections need to be distinguished from those that result from malicious transmission
Summarized effective techniques to improve observational skills
1. There are several techniques used to improve observational skills such as paying attention to all of the details knowing that humans are not included to pay attention 2. This means that to be a good observer, you have to make a conscious effort to examine our environment systematically 3. Other skills are: a) to be consciously observing everything and turn off our filters to act like data collecting robots, b) carefully gather all of the available information and leave interpretation until we have as much information as possible and c) finally document every observation with photographs and written notes to help piece together the crime and so it is imissable in court
Two people witness the same car accident. Each person provides an eyewitness account and is confident it is 100% accurate. However, the eyewitness accounts differ. Based on the information about observations and perceptions, explain how they can have two different accounts of the same event.
1. These two people can have different accounts of the same event because a person's perception can be limited in order to observe the most important information. 2. as a result, the way they viewed their surroundings may not accurately reflect what really happened 3. the focus and concentration of the eyewitnesses could have been different, making their accurate accounting of events different 4. their emotional states could also have influenced their ability to observe the events clearly because certain feelings like anxiety, happy, or depression can make them more likely to not notice their surroundings 5. other factors could include: a) if the witnesses are alone or with a group of people b) the number and types of people an animals around c) the type and level of activity around them d) their state of health e) visual capabilities f) fatigue and stress levels and emotional involvement g) any distractions from phones, disguises used, h) their preception differences, i) among of time observed, j) ability to make quick decisions, k) their motivational or cognitive bias, l) what their personal beliefs, motives, and prejudices, and also effects what they observed
what is the gram staining procedure?
1. Thin smears of bacterial cultures to be tested should be air-dried and flame fixed on clean glass slides. Fix by passing the slide, smear side up, over an alcohol or Bunsen burner five or six times. 18 to 24 hour cultures will give the best results 2. Heat fixed smear is covered with a basic purple dye, CRYSTAL VIOLET- primary stain a) apply Gram crystal violet stain (Hucker formula) from an eye dropper or dropper bottle. Slide should be flooded with stain and let stand for one minute. Gently rinse slide with water from a dropper or by dipping in a beaker or cup of clean water. Rinsing should be sufficient to remove excess stain 3. Purple stain is washed off and smear is covered with a mordant-IODINE a) flood smears with Gram iodine (serves as a mordant, or dye retainer) and let stand for one minute. rinse with clear water as above 4. Slide is washed with ALCOHOL: decolorizing agent a) decolonize smears with 95% ethyl alcohol by applying one drop at a time- just until no more color runs off- for approximately 30 seconds. Decolorization time is determined primarily by the thickness of the smear-shorter for thin smears, longer for thick smears. It is very important not to over-decolorize in this step. Rinse with water as above. This rinsing step is necessary to stop the action of the alcohol decolorizer 5. alcohol is rinsed and slide is stained with SAFRANIN- counterstain a) apply Gram safranin counterstain and let stand for 30-45 seconds. This step saves to stain those bacteria (Gram negative) not holding the crystal violet after step 4. Rinse very briefly with water as above. Air or blot dry the slides and examine under oil immersion 6. NOTE: upon examination, GRAM POSITIVE BACTERIA will appear to be stained a BLUISH BLACK COLOR WHILE GRAM NEGATIVE SPECIES WILL BE RED. During the various steps it is important not to allow any of the stains to evaporate to dryness on the slides. Simply add more stain until the recommended staining period is over and the slides are ready to be rinsed. Common spring type wooden clothespins make excellent slide holders during flaming, staining, and rinsing a) all stains are applied to one side and pick one stain to take up which tells us what it is b) In gram positive, the alcohol won't penetrate so the color stays c) in gram negative, the alcohol disrupts thin cell wall of Gram negative and washes out the color
what is vitamin C and how do you test for it?
1. Vitamin C (ascorbic acid) is one of the important substances that contributes to the maintenance of good health 2. it should be included regularly in a normal diet 3. Ascorbic acid is water soluble and a reducing agent 4. An indicator solution (dichlorindophenol) is used to test for Vitamin C 5. The blue indicator solution will become colorless in the presence of vitamin C and remains blue in the absence of vitamin C
what are viruses?
1. acellular (not cellular) 2. can only be seen with an electron microscope 3. made up of a nucleic acid (DNA/RNA) and a protein coat 4. can only reproduce within a host cell
what is simple stain?
1. aqueous or alcohol solution of a single basic dye 2. highlight the entire organism so that cellular shape and basic structures are visible 3. a MORDANT may be added to intensify the stain 4. ex: methylene blue, safranin, carbolfuchsin, iodine
What is fungi?
1. eukaryotes- have true nucleus and membrane bound organelles 2. unicellular or multicellular 3. cell walls composed of CHITIN 4. fungi can reproduce asexually or sexually 5. fungi obtain nutrients by absorbing organic materials from their environment 6. Ex: molds, yeast, mushrooms
What is the chain of custody?
1. in securing the evidence, maintaining the chair of custody is essential 2. this process ensures that the evidence has been responsibly handled as it was passed from the crime scene to a courtroom a) how we collect and categorized evidence by logging and documenting and categorizing evidence and then pass it on carefully so the evidence is not thrown out by the judge
What are the instruments used in microscopy? What is light microscopy?
1. in the seventeenth century ANTONI VAN LEEUWENKOEK used a simple microscope that had only one lens and could magnifying a microbe 300x a) first person to see bacteria 2. LIGHT MICROSCOPY: refers to the use of any kind of microscope that uses visible light to observe specimens a) compound light microscopy b) dark field microscopy c) phase-contrast microscopy d) differential interference contrast microscopy (DIC) e) fluorescence microscopy f) confocal microscopy
What is a latent, patent, and plastic fingerprint?
1. latent fingerprints: a concealed fingerprint that is made visible through the use of powders or forensic techniques 2. patent fingerprint: a visible fingerprint produced when fingers coated with blood, ink, or some other substance touch a surface and transfer their print to that surface 3. plastic fingerprint: a three dimensional fingerprint made in soft material such as clay, soap, or putty
why do you stain bacteria?
1. living bacteria are almost colorless an lack sufficient contrast with the liquid in which they are suspended to be clearly visible a) staining bacteria increases their contrast with their surroundings so that they are more visible 2. The staining process kills the bacteria, however, and living processes such as movement are no longer visible 3. Most bacterial stains are salts a) when salts are dissolved they separate into positive and negative ions. b) salts used as stains have one ion that appears colored in the visible spectrum c) the stain, methylene blue, is the the salt methylene blue chloride d) the color of the stain is in the positively charged methylene blue ion and when it is dissolved it dissociates as follows: methylene blue chloride → methylene blue⁺ + chloride⁻ 4. Bacterial cells have a slight negative charge when the pH of their surroundings is near neutral, which it generally is when they are actively growing a) the negatively charged bacterial cell combines with the positively charged methylene blue ion, with the result being that the cell is stained and looks blue. b) the opposite charges of the cell and the stain ion attract each other and the methylene blue "sticks" (bonds) to the cell
What is vaccination?
1. may 4, 1779 Edward Jenner found a way to protect people for smallpox a) inoculated healthy girl with cowpox-milder disease b) the girl became sick with cowpox but fully recovered c) never against contracted either smallpox or cowpox 2. Process is called VACCINATION- from the Latin word Dacca meaning cow avirulent microorganisms used for preventative inoculations 3. protection from disease provided by vaccination is called IMMUNITY
what is an electron microscopy?
1. objects smaller than about 0.2 um must be examined by EM a) ex: viruses, internal structures of cells b) a beam of electrons is used instead of light 2. there are two types of electron microscopes a) transmission electron microscope (TEM) b) scanning electron microscope (SEM)
What are the benefits of microbes to human welfare?
1. only a minority of all microbes are pathogenic-disease causing 2. the majority of microbes benefit humans and plants in many ways 3. BENEFITS OF MICROBES: a) recycling vital elements b) sewage treatment to recycle water c) cleaning up pollutants d) insect pest control e) genetic engineering 4. Normal Microbiota (flora): a) protect us from disease causing microbes b) produce useful substances like vitamin K and B
what is algae?
1. photosynthetic eukaryotes 2. unicellular 3. cell walls made up of a carbohydrate complex called CELLULOSE 4. abundant in fresh and salt water 5. Ex: diatoms
what are the seven s's of crime scene investigation?
1. securing the scene 2. separating the witnesses 3. scanning the scene-determine primary/secondary 4. seeing the scene-photos 5. sketching the scene 6. searching for evidence 7. securing and collecting evidence
what are the different staining techniques?
1. simple stain 2. differential stain 3. special stain
how do you prepare smears of specimens for light microscopy?
1. staining simply means coloring the microorganism with a dye 2. before staining, the specimen must be FIXED (attached) to the microscope slide a) have to heat slide by waving it to attach and kill bacteria so you can stain it 3. fixing kills the microbe and attaches them to the slide a) smear separates and isolates them across the slide 4. WHEN A SPECIMEN IS TO BE FIXED: a) a thin film of material containing the microbe is spread over the slide (smear) b) smear air dries c) slide is fixed by heat d) stain is applied and washed off e) slide is blotted with absorbent paper f) ready for examination
what is microbial forensics? what is the value of the human microbiome?
1. the forensic potential of microorganisms is becoming increasingly apparent as a consequence of advances in molecular sciences and genomics 2. microbes, and in particular bacteria, can impact upon forensic investigations 3. There is increasing evidence that humans have an extremely diverse 'microbiome' that may prove useful in determining ethnicity, country of origin, and even personal identity a) the health department uses contact tracing and collecting data on COVID-19 b) can help ID causes of a certain outbreak, origins of diseases being spread, stomach contract, and contamination 4. the human microbiome differs between regions of the body a) may prove useful for determine the nature of stains such as those caused by saliva, blood, sperm, and vaginal fluid b) it may even be possible to link the stains to the person responsible for them c) microbiome: population of species that lives in our body- there is more foreign DNA in our body than our own DNA 5. microorganism can therefore provide evidence in many difference forensic scenarios but most of the work is still at the experimental stage and there are therefore many opportunities for further a) using microbial in investigation is new and growing quickly and many more opportunities have yet to be discovered b) microbial can help us ID a person's environment c) gut is coli that help us breakdown food and differs foremother animals (helps you tell if it is an animal or human)
what are differential stains? What are gram positive and gram negative?
1. the gram stain is the most frequently used differential stain used for bacteria 2. developed in 1884 by HANS CHRISTIAN GRAM a) in 1885 Hans Christian Gram was working in a lab, staining bacteria b) he was not satisfied with the staining technique he was using because not all bacteria seemed retain the stain equally c) when he considered to be a defect in the staining technique eventually led to one of the most widely used tests for distinguishing bacteria from one another d) the differential staining method became known as the Gram Stain 3. classifies bacteria into two large groups: a) Gram + b) Gram - 4. GRAM POSITIVE: bacteria that retain crystal violet in its cytoplasm a) have a thicker pepetidoglycan cell wall b) combination of crystal violet and iodine for the (CV-I) complex A) CV-I complex forms inside the cells B) complex is too large to exit out of the thick peptidoglycan layer C) thus cell retains purple stain and is classified a Gram + c) STAINS PURPLE 5. GRAM NEGATIVE: bacteria that lose the dark violet color after decolorization a) retain counter stain-safranin b) cell wall is composed of a layer of lipopolysaccharide c) alcohol disrupts the outer layer and the CV-I complex is washed out d) STAINS REDDISH-PINK 6. The distinction between Gram Positive and Gram negative is based upon the inability of the purple stain (crystal violet) to be flushed out of the cell during the Gram staining procedure a) this seems to be related to the different chemical and/ or structural makeup of the cell walls of gram-positive and gram-negative bacteria b) because their structures are different they accept and retain stains in different ways c) gram staining is generally the first step in identifying an unknown bacterial species and is routinely used in even the most sophisticated microbiological laboratories
What is the germ theory of disease?
1. the realization that yeasts play a crucial role in fermentation was the first link between the activity of microorganisms and the physical and chemical changes in organic materials 2. this may have similar relationships with plants and animals-microorganisms might cause disease 3. The germ theory was a hard concept to accept because people believed that disease was a punishment for crimes or misdeeds 4. 1860's Joseph Lister applied the germ theory to medical practices- he knew that phenol (carbolic acid) kills bacteria and started using it during surgery-it greatly reduced infections and death in patients a) other surgeons quickly adopted his practices 5. Robert Koch-1876-discovered the bacteria that caused anthrax in cattle and sheep-bacillus anthraces 6. THESE STEPS ARE KNOWN AS KOCH'S POSTULATES: a) cultured bacteria on nutrients and injected samples into healthy animals b) animals became sick and died c) cultured bacteria and compared them to the original d) the two sets of bacteria were the same
How has fingerprinting been helpful in the US?
1. though the technique and its systematic use originated in Great Britain, fingerprinting was developed to great usefulness in the United States 2. where in 1924, two large fingerprint collections were consolidated to form the nucleus of the present file maintained by the Identification Division of the FBI 3. The division's file contained the fingerprints of more than 90 million persons by the late 20th century. Fingerprint files and search techniques have been computerized to enable much quicker comparison and identification of particular prints
What are protozoa?
1. unicellular 2. eukaryotes 3. move by pseudopods, cilia, or flagella 4. live as free entities or as parasites
what are special stains?
1. used to color and isolate specific parts of microorganism such as flagella, endospores, or to reveal the presence of capsules a) negative staining for capsules b) endospore staining c) flagella staining
What is the acid-fast stain?
1. uses red dye-carbolfuchsin 2. binds only to bacteria that have a waxy material in their cell walls 3. Ex: mycobacterium tuberculosis and mycobacterium leprae
What is the difference between whorls, arches, and loops on fingerprints?
1. whorls are usually circular or spiral in shape 2. Arches have a mound like contour, while tented arches have a spikelike or steeple appearance in the center 3. Loops have concentric hairpin or staple shaped ridges and are described as "radial" or "ulnar" to denote their slopes a) ULNAR LOOPS SLOPE TOWARD THE LITTLE FINGER SIDE OF THE HAND, RADIAL LOOPS TOWARD THE THUMB b) Fingerprints are no mirror images on both hands c) Radial bone is thumb side d) Pinky is ulnar bone e) analyze the loop by looking where it goes up and where it returns to f) if the loop opens up towards the thumb and it loops around then it is radial g) if the loop opens up towards the pinky than it is ulnar h) IT IS NOT WHERE THE PEAK OF THE LOOP POINTS, IT IS WHERE IT OPENS UP 4. Loops constitute about 65% of the total fingerprint patterns 5. Whorls make up about 30% 6. Arches and tented arches together account for the other 5% 7. THE MOST COMMON PATTERN IS THE ULNAR LOOP
What is archaea?
Archaea: ancient bacteria 1. Prokaryotes 2. Cell walls lack peptidoglycan 3. live in extreme hostile conditions 4. ARCHAEA ARE DIVIDED INTO THREE MAIN GROUPS: a) METHANOGENS: produce methane as a waste produce from respiration b) EXTREME HALOPHILES: live in extremely salty environments such as the Great Salt Lakes and the Dead Sea c) EXTREME THERMOPHILES: live in hot sulfurous water such as hot springs at Yellowstone National Park
What is a bacteria?
Bacteria: singled celled organisms 1. PROKARYOTES: lack true nucleus, lack membrane bound organelles 2. bacteria are enclosed in cell walls made up of a carbohydrate and protein complex called PEPTIDOGLYCAN 3. Bacteria reproduce asexually by the process of BINARY FISSION 4. Bacteria obtain nutrition from organic chemicals from dead or living organisms 5. Some bacteria can make their own food through the process of PHOTOSYNTHESIS OR CHEMOSYNTHESIS
What is the technique of fingerprinting called? What does it involve and what are the different techniques?
DACTYLOSCOPY- THE TECHNIQUE OF FINGERPRINTING 1.INK FINGERPRINTING: involves cleaning the fingers in benzene or ether, drying them, then rolling the balls of each over a glass surface coated with printer's ink a) each finger is then carefully rolled on prepared cards according to an exact technique b) Designed to obtain a light gray impression with clear spaces showing between each ridge so that the ridges may be counted and traced 2. LATENT FINGERPRINTING involves locating, preserving, and identifying impressions left by a culprit in the course of committing a crime a) in latent fingerprints, the ridge structure is reproduced not in ink on a record card but on an object in sweat, oily secretions, or other substances naturally present on the culprit's fingers 3. most latent prints are colorless and must therefore be "developed" or made visible, before they can be preserved and compared a) this is doe by brushing them with various gray or black powders containing chalk or carbon combined with other agents b) the latent impressions are preserved as evidence either by photography or by lifting powered prints on the adhesive surfaces of tape
True or False: Good observation skills come naturally to investigators; they do not need to be trained.
False: Investigators need to be trained to have good observational skills
True or False: The innocence project is an organization that seeks to get convicted killers out of prison
False: The Innocence Project is an organization that reexamines post-conviction cases using DNA evidence to provide conclusive proof of guilt or innocence
True or False: Fingerprints are formed deep within the dermis layer of the skin
False: fingerprints are formed on the basal layer of the skin where new skin cells are produced
True or False: Fingerprints are generally considered to be a form of class evidence
False: fingerprints are generally considered to be a form of individual evidence
True or False: If we remember seeing something happen, we can trust that it happened just as we think it did
False: our brains can be faulty so we may remember seeing something that is different from what actually happened
How are fingerprints classified?
Fingerprints are classified in a three way process: 1. by the shapes and contours of individual patterns 2. by noting the finger positions of the pattern types 3. by relative size, determined by counting the ridges in loops and by tracing the ridges in whorls 4. There are several variants of Henry system, but that used by the Federal Bureau of Investigation (FBI) in the United States recognizes eight different types of patterns: a) radial loop b) ulnar loop c) double loop d) central pocket loop e) plain arch f) tented arch g) plain whorl h) accidental
What are the studies of immunology and virology?
IMMUNOLOGY: THE STUDY OF IMMUNITY 1. vaccines are available for numerous diseases including: a) measles, mumps, rubella b) chicken pox c) pneumonia d) influenza e) polio 2. smallpox vaccine was so effective that the disease has been eliminated 3. it is estimated that polio will be eradicated within a few years because of the polio vaccine VIROLOGY 1. In 1935 Wendell Stanley demonstrated the differences that the tobacco mosaic virus was fundamentally different from other microbes 2. The development of the electron microscope in the 1940's has allowed scientists to study the structure of viruses in great detail
what are minutiae? Name a couple of types of minutiae?
Minutiae: the combination of details in the shapes and positions of ridges in fingerprints that makes each unique; also called ridge characteristics EXAMPLES OF MINUTIAE (make sure to know what each looks like) 1. core 2. delta 3. trifurcation 4. double bifurcation 5. eye (enclosure of island) 6. Spur (or hook) 7. bridge 8. dot (of very short ridge) 9. island ridge (or short ridge) 10. fork (or bifurcation) 11. ending ridge (including broken ridge)
How do you name and classify microorganisms?
NOMENCLATURE: naming 1. SCIENTIFIC NOMENCLATURE ASSIGNS EACH ORGANISMS TWO NAMES: a) Genus: first name and always capitalized b) species: second name and not capitalized 2. Ex: Staphylococcus aureus 3. By putting the shape and arrangement together, we can describe the morphology of the bacteria a) for example, if a bacterium is round and is found in a chain we would call it a streptococcus b) if it is a rod and is found in pairs, it is a diplobacillus
True or False: Fingerprint impressions left on a smooth surface consist of natural secretions of the sweat pores found in the friction ridge of the skin
True
True or False: NGI improves the speed and accuracy of fingerprint searches because it electronically accesses fingerprints from local, state, and national agencies
True
True or False: The type of powder used to dust prints will vary depending upon the weather conditions when the print is lifted
True
Fingerprints that are actual indentations left in some soft material such as clay or putty are referred to as: a) plastic fingerprints b) patent fingerprints c) latent fingerprints d) indented fingerprints
a) plastic fingerprints
the use of fingerprint in identification is not perfect because: a) the current technology depends on humans to analyze the information and humans make mistakes b) many people have the same exact fingerprints c) people can easily change their fingerprints d) all of the above
a) the current technology depends on humans to analyze the information and humans make mistakes
what does a tented arch on a fingerprint look like?
arch: a fingerprint pattern in which the ridge pattern originates from one side of the print and continues to the other side
the presence of two deltas in a fingerprint indicates: a) scar tissue b) that a print is a whorl pattern c) that a print is a loop pattern d) that a print has a core
b) that a print is a whorl pattern
Fingerprints are formed: a) shortly after birth b) at about two years of age c) at 10 weeks gestation (pregnancy) d) at conception
c) at 10 weeks gestation (pregnancy)
The Innocence Project found that most faulty convictions were based on: a) out of date investigating equipment b) poor DNA sampling c) inaccurate eyewitness accounts d) officers not thoroughly observing a crime scene
c) inaccurate eyewitness accounts
what does a core of a fingerprint look like?
core: a center of a loop
what does a delta on a fingerprint look like?
delta: a triangular ridge pattern created when ridge patterns diverge
True or False: fingerprints of the left hand are mirror images of the fingerprints on the right hand
false: fingerprints of the left hand are not mirror images of the fingerprints on the right hand
what does a ulnar loop on a fingerprint look like?
loop: a fingerprint pattern in which the ridge pattern flows inward and returns in the direction of the origin