Uv Light Effect And Repair Lab Report

1642 words - 7 pages

Lab Report 3: Effect of UV Light on Microbial Growth
Kristin Holmes – April 2, 2013
PURPOSE: The purpose of this lab is to determine the effects of ultraviolet light on microbial growth and the effectiveness of the repair mechanisms of light repair and dark repair on UV damage.
Can Ultraviolet (UV) light be a viable form of sterilization and/or disinfection? This lab experiment will look to examine and answer that question. UV light is a form of electromagnetic radiation that is invisible to the human eye. It has a short wavelength and is considered high energy which allows it to pass through some materials. The biological effects are potentially devastating based on the ...view middle of the document...

The two mechanisms for repair that are being examined in this experiment are Light repair and Dark repair. Light repair is also known as photoactivation. Light repair uses photolyase which detects and attaches to the abnormal pyrimidine binding sites with single protons and single electrons projecting towards the dimer. The proton and electron projections create a cascade of reactions that nudge the mutated nucleotides back into place. One of the cool things is that the proton and electron are not lost in the reactions and return to the photolyase to be used again. Sadly, mammals do not contain photolyase any longer (lost in evolution). (Krakauer) The other method of repair is Dark repair – also known as excision repair. During Dark repair the damaged DNA is excised and a new strand of the missing DNA is copied in by DNA polymerase. (Menard)
This experiment will examine the effects of timed exposure to short-wave UV light and the repair effects of both methods of repair mentioned above on the bacteria Serratia marcescens.
Organisms: Serratia marcescens cultured in broth.
Medium: 7 Nutrient Agar (NA) plates.
Miscellaneous: Sterile cotton swabs, 5 filter paper templates, aluminum foil, Bunsen burner and UV light box.
This was a “bench effort” experiment. To begin with the 7 NA plates were labeled with initials, bacteria, the date of 3/26/13 and each numbered 1 through 7. Using sterile swabs, each NA plate was swabbed with S. marcescens bacteria (to completely cover the agar).
Plates 1 & 2 were exposed to UV light for 30 seconds, with the lids removed and covered by a filter paper mask. Plate 3 was then exposed to the UV light for 3 minutes without the lid and covered by a filter paper mask. Plates 4 & 5 were exposed to UV light for 3 minutes as well; however the lids remained on and they were each covered with a paper filter mask. Plates 6 & 7 were not exposed to UV light at all.

Plates 2, 5, & 7 were stacked together, wrapped in aluminum foil, and set closest to the wall under the window. The remaining plates were spread in a row giving them exposure to the natural light coming in through the window. All plates were left on the worktable for 48 hours.
Plate | Growth in exposed areas of mask | Growth in area covered by mask | Interpretation |
1 | Several Single colonies | Confluent | Damage, some repair |
2 | Very little growth – a few single colonies of bacteria have grown near edges of mask cover. | Confluent | Damage, very minimal repair |
3 | Confluent
(This plate should have shown extensive damage and no regrowth.) | Confluent | Inconclusive – It appears the lid may have not been removed. Should have seen no growth in exposed area of mask with much more defined edges between exposed and covered areas. |
4 | Confluent | Confluent | No damage |
5 | Confluent | Confluent | No damage |
6 | N/A | Growth | Control |
7 | N/A | Growth | Control...

Other Papers Like Uv Light Effect and Repair Lab Report

Global and China Medical Endoscopic Cold Light Source Industry 2014 Market Research Report

1344 words - 6 pages Global and China Medical Endoscopic Cold Light Source Industry 2014 Market Research Report The report firstly introduced Medical endoscopic cold light source basic information included Medical endoscopic cold light source definition classification application industry chain structure industry overview; international market analysis, China domestic market analysis, Macroeconomic environment and economic situation analysis and influence

A Lab Report Of An Object In Freefall And The Effects Of Gravity

1121 words - 5 pages Purpose:The purpose of this lab is to prove that the acceleration of gravity is 9.8m/s/s. We did this by taking a time lapse photo of a ball dropped with a meter stick next to it. While the ball was dropped, a strobe light was flashing 3000 times per second, which created measurable points of the balls descent. Then we did a few different graphs of the data points by hand and computer.Procedure:1. Set up a meter stick vertically against a black

Lab Report 2 Laboratory Techniques and Measurements Template

587 words - 3 pages General Chemistry I Lab 2: Laboratory Techniques and Measurements Purpose Procedure Data Data Table 1: Length measurements. Object Length (cm) Length (mm) Length (m) CD or DVD Key Spoon Fork Data Table 2: Temperature measurements. Water Temperature (°C) Temperature (°F) Temperature (K) Hot from tap Boiling Boiling for 5 minutes Cold from tap Ice water – 1


2634 words - 11 pages . Spectrophotometry Spectrophotometry is a technique that uses the absorbance of light by an analyte (the substance to be analyzed) at a certain wavelength to determine the analyte concentration. UV/VIS (ultra violet/visible) spectrophotometry uses light in UV and visible part of the electromagnetic spectrum. Light of this wavelength is able to effect the excitation of electrons in the atomic or molecular ground state to higher energy levels, giving rise

Aarkstore - Heraeus Noblelight Fusion UV Inc. - Strategic SWOT Analysis Review

963 words - 4 pages  Aarkstore - Heraeus Noblelight Fusion UV Inc. - Strategic SWOT Analysis Review Summary “Heraeus Noblelight Fusion UV Inc. - Strategic SWOT Analysis Review” provides a comprehensive insight into the companys history, corporate strategy, business structure and operations. The Market Research Report contains a

Ozone Depletion

1381 words - 6 pages . Current studies indicate that ultraviolet rays could be disastrous to the marine eco-system. High UV concentration causes phytoplankton, microscopic organisms at the base of the food chain, to decrease their reproductive activity. Although there is no serious widespread effect now, the problem may escalate in future years.3 Numerous studies have proven that ultraviolet radiation, in both the UV-A and UV-B forms, causes skin cancer. Of the

Anatomy Case Study on the Evolution of Skin Color

1194 words - 5 pages add in. In order to see which people get skin cancer the most, you would have to take that persons genetic history into consideration. With Brenda and Eatons results, you can tell that after exposure to UV light, the folate count dropped, which can lead to miscarriages and other birth defects. The effect of UV light on folate levels makes the count drop. Folate is linked to natural selection because the folates deplete from UV light

Industrial Survey

1081 words - 5 pages more than 1000 in a dark room. The light intensity of a room is measured by using a photometer. After applying developer, the defect of the specimen can be seen more clearly by using a UV ray machine in a dark room. During NDT ILSAS Lab session, PT process is done by spraying the chemicals onto the specimen. CONCLUSION In conclusion, I have learned that PT method shows flaws on an object which can be clearly seen by our eyes. I obtained

Ozone & Its Effects

2553 words - 11 pages  molecules to create two O3 molecules. These ozone molecules absorb UV light between 310 and 200 nm, following which ozone splits into a molecule of O2 and an oxygen atom. The oxygen atom then joins up with an oxygen molecule to regenerate ozone. This is a continuing process which terminates when an oxygen atom "recombines" with an ozone molecule to make two O2 molecules. O + O3 → 2 O2 The overall amount of ozone in the stratosphere is

Electro Cosmetic Report

2029 words - 9 pages epidermis at all. It has a germicidal effect, so can be used to sterilise working surfaces etc. Fluorescent tube ultraviolet lamps operate in quite a similar way to the fluorescent light tubes that are in use all around us. These are made with a special type of glass named vitaglass, this is transparent to UV light down to 280nm. UVA and UVB will get through this but the UVC is absorbed. Inside the glass tube is an almost vacuum i.e. Very Low pressure

Lab For Envbiroemnt

1219 words - 5 pages this would be and if this is a repeatable conducive. • What effect does the intensity of light have on the rate of photosynthesis (measured as the number of oxygen bubbles)? • The Hypotheses given in the lab shows the increase in light concentration, an accelerated photosynthesis process went on with the 0-watts to 100-watts. The average number of bubbles in the 0 watt study was 2 bubbles in 1 hour. After the increase of a 25 watts

Related Essays

Uv Lab Report

1707 words - 7 pages State the problem or question: The following question that associated with this lab was if the strength of the SPF in four different types of products would prevent or continue the growth of light sensitive yeast when tested. The yeast is essentially our skin and the growth of the yeast shows that the SPF of the product tested was effective. If the yeast growth was muted, then the SPF of the product did not protect our skin. Background

Lab Report On Effect Of Black Walnuts On Surrounding Vegetation

522 words - 3 pages When one views the ground nearby a black walnut tree, a view of life is very sporadic and almost desolate. Many large trees provide much shading but the grass seems to grow even more economically in these areas. From these observations it appears that the black walnuts contain some type of ingredient that serve as a toxin for the plant life around the base of the tree. At first, a black walnut was taken and the outer layers were collected

Bacteria And Antibiotics Lab Report

1591 words - 7 pages BACTERIA AND ANTIBIOTICS LAB REPORT Bryan Bennett Ms. Johnson Biology 09 period 8 March 12, 2013 Introduction: 1. Eubacteria -Has cell wall with peptidoglycan -They can live nearly anywhere on earth (sky to underground) -Unicellular -Prokaryotic -Reproduce Asexually Archaebacteria -Cell wall without peptidoglycan -Live in environments without oxygen (anaerobic) -Prokaryotic -Unicellular -Reproduce Asexually

Netw240 Week 2 Lab Report: Linux Commands And Directories

1575 words - 7 pages Name: | | DSI# | | Date | | NETW240 Week 2 Lab Report: Linux Commands and Directories Step 2: File System Navigation 1: Display a long listing of the root ( ⁄) directory. Enter ls -l ⁄ Verify that the output is from the ⁄etc directory and is a long list. What type of files may you find in this directory? Write your answer below. binbootcgroupdevetchomeliblost