Introduction Bacteria are grouped into two categories as Gram positive and Gram negative. The bacteria that retain the color of the primary stain are gram positive and the bacteria that lose the color of primary stain are called gram negative bacteria. Gram positive cells have a thicker peptidoglycan layer and doesn 't contain the outer membrane. Gram positive cells will retain the primary stain of crystal violet because they have a thick outer layer of peptidoglycan that traps the dye among its high degree of teichoic acid crosslinks. On the other hand, Gram (-) cells have a thin peptidoglycan layer and an outer membrane, gram negatives have an outer membrane made up of Lipopolysaccharide, proteins and prions and have thin peptidoglycan layer with higher lipid content that are targeted by the alcohol/ acetone decolorizer and makes the cell’s outer layers more porous, thus they are unable to retain the primary stain. In order to know the morphology of bacteria, the gram staining procedure was conducted by using four different kinds of chemicals like Crystal Violet, as a primary stain; Gram’s Iodine, as the mordant for enhancing the crystal violet staining; 95% Ethanol, as the decolorizer for the Gram-negative cells and Safranin, as the counterstain, giving the Gram-negative cells its pink color. …show more content…
The production of acids lowers the pH of the media. After incubation, methyl red indicator is added to the medium for the test of production of mixed acid. If the color changes to red, then the test is said to be positive for the production of mixed acids, if the color changes to orange, the result is inconclusive and is further incubated and if the color doesn 't changes at all, then the result is said to be negative with no production of mixed acids (Leboffe and Pierce
The first day an unknown sample was assigned to each group of students. The first test applied was a gram stain to test for gram positive or gram-negative bacteria. The morphology of the two types of bacteria was viewed under the microscope and recorded. Then the sample was put on agar plates using the quadrant streak method for isolation. There were three agar plates; one was incubated at room temperature, the second at 30 degrees Celsius, and the third at 37 degrees Celsius. By placing each plate at a different temperature optimal growth temperature can be predicted for both species of bacteria.
The Gram positive bacteria has been nicknamed Posi. The Gram positive species’ morphology includes having an opaque opacity with a smooth margin. The moisture content of the Gram positive species is shiny and the pigmentation is gold. The Gram positive species grows at an optimal temperature of 37°C. The shape of the Gram positive species is a cocci, with an arrangement of grapelike clusters. The Gram positive species’ size ranges from .5-1.5 µm. Oxygen requirement of the Gram positive species is facultative, and has complete lysis of red blood cells. All results are summarized in Table
The purpose of this study is to identify an unknown bacterium from a mixed culture, by conducting different biochemical tests. Bacteria are an integral part of our ecosystem. They can be found anywhere and identifying them becomes crucial to understanding their characteristics and their effects on other living things, especially humans. Biochemical testing helps us identify the microorganism present with great accuracy. The tests used in this experiment are rudimentary but are fundamental starting points for tests used in medical labs and helps students attain a better understanding of how tests are conducted in a real lab setting. The first step in this process is to use gram-staining technique to narrow down the unknown bacteria into one of the two big domains; gram-negative and gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species. These biochemical tests are process of elimination that relies on the bacteria’s ability to breakdown certain kinds of food sources, their respiratory abilities and other biochemical conditions found in nature.
The results of the gram stain test were cocci and purple. This indicated that the unknown bacteria were gram positive. The gram stain test eliminated Escherichia coli, Klebsiella pneumonia, Salmonella enterica, and Yersinia enterocolitica as choices because these bacteria are gram negative. Next a Blood Agar plate was used because in order to do a MSA or a Catalase test there needs to be a colony of the bacteria. The result of the Blood Agar plate was nonhemolytic.
The purpose of this laboratory is to learn about cultural, morphological, and biochemical characteristics that are used in identifying bacterial isolates. Besides identifying the unknown culture, students also gain an understanding of the process of identification and the techniques and theory behind the process. Experiments such as gram stain, negative stain, endospore and other important tests in identifying unknown bacteria are performed. Various chemical tests were done and the results were carefully determined to identify the unknown bacteria. First session of lab started of by the selection of an unknown bacterium then inoculations of 2 tryptic soy gar (TSA) slants, 1 nutrient broth (TSB), 1 nutrient gelatin deep, 1 motility
In the pH homeostasis lab, 6 experiments were conducted. The hypotheses were: If base is added to water then the pH will increase; If acid is added to water then the pH will decrease; If base is added to homogenate, then the pH will increase; If acid is added to homogenate, then the pH will decrease; If acid or base is added to buffer, then the pH will remain the same. After the experiments were conducted, the graphs were somewhat similar to the hypotheses.
The Gram stain is a system used to characterize bacteria based on the structural characteristics of their cell walls. A Gram-positive cell will stain purple if cell walls are thick and a Gram-negative cell wall appears pink. Most bacteria can be classified as belonging to one of four groups (Gram-positive cocci, Gram-positive bacilli, Gram-negative cocci, and Gram-negative bacilli) (Phenotypic analysis. (n.d.).
I was given unknown organism #14, in order to find out what organism I had, I had to perform several different biochemical tests to identify it. Starting with the Gram stain test, which is performed to differentiate Gram-positive and Gram-negative cells. After staining, when observed through the microscope Gram-positive cells are a purple color with thick peptidoglycan cell walls. Gram-negative cells are a pinkish/red color with thinner cell walls. (handout G. s.) My organism was observed to be pinkish rod shaped meaning it is Gram-negative bacteria.
Color can be viewed based on three different dimensions. The Munsell color system classifies colors based on hue, value, and chroma. Hue describes the color family or underlying tone (e.g., green, blue, red). Value describes the brightness or darkness on the scale on zero to ten, zero being white and ten being black. Chroma describes the saturation or vividness of a color. The appearance of teeth is affected in three ways by whitening. First, whitening reduces the amount of chroma in the tooth—the pigment or intensity of color is reduced. Second, whitening changes the hue, or color, or the teeth. Thirdly, whitening changed the value of the teeth.
Halitosis is the medical term for Bad Breath. When people think of bad breath they automatically think that food is the cause of the bad odor. When in reality there are many factors that can lead up to bad breath. Yes food is one of them but there are other reasons as to why a person may be experiencing bad breath or teeth staining. A person may experience bad breath or teeth staining because they may have a health problem that is causing the odor other factors are smoking and chewing tobacco.
This lab has two sections. The first section deals with fermentation. The purpose of the fermentation lab is to alter 5 different independent variables (temperature, acid ph, alkali ph, enzyme concentration, and substrate concentration), to learn about their effects on the ongoing process of fermentation.
Everyone has teeth, and society likes them to be as white as possible. But does everyone know the parts of the tooth? The tooth has four parts: dental pulp, dentin, enamel, and cementumcentenum. Dental pulp is the center part of the tooth and is made of tissue and nerves. Dentin is connected to the dental pulp and is the second hardest part of the tooth. Enamel is the hard, outer layer that surrounds the tooth. Enamel cannot be repaired or replaced. One can only prevent its loss, which is why we brush our teeth so often to help eliminate the plaque and acids that certain sodas and other sugary drinks try so hard to remove. Without enamel, teeth would erode within days of their coming in. And last but not least, cementumcentenum. CementumCentenum covers the root of the tooth and it anchors the root to the skin.
Introduction Grouting is a method of injecting a pumpable liquid, suspension, emulsion or mortar called grout. It also consists of more or less pervious material that may be natural which is soil or rock or in other case it consists of man-made material which is mansory or concrete. Grout is usually injected through grout holes. The purpose of grouting is to improve the properties of the material. Increase in stress by means of increasing strength and reducing or increasing its permeability.
We are trying to find out how much acid it takes to neutralise the alkaline. But there are many things that could affect my final result and I think that the main thing will be measuring the acid and alkali accurately so that the experiment was fair. Prediction We planned the experiment as a class and so we have all predicted that the same thing will happen to the results. But a few of us disagreed. and I was one of them.
pH levels shows how acidic or basic a substance is. A substance that is neither acidic or basic is called neutral. pH levels are very important in measuring the acidity of something for scientists. The scale ranges from 0 to 14. A pH of 7 is neutral, a pH less than 7 is acidic, and a pH greater than 7 is basic. Sour and fruity candy are very acidic. Some sour candies reach very low pH levels, such as warhead sour spray, which has a pH of one p...