Biology

Preparation of a bacteria smear and the simple stain technique. 1) Identify the steps taken in the preparation of a bacterial smear to prevent contamination of the culture and yourself working with a bacterial smear?2) Summarize the “fundamental theory” of simple staining. hint: what scientific property allows the dyes t bind the bacterial cell wall?

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3) What would happen if you placed a large drop of water on a slide rather than a loopful, when preparing a bacterial smear? 4) Discuss the possible outcomes if an air-dried smear were not heat fixed before proceeding to the staining step. 5) While viewing a slide of a “pure” culture you observe two …

Preparation of a bacteria smear and the simple stain technique. 1) Identify the steps taken in the preparation of a bacterial smear to prevent contamination of the culture and yourself working with a bacterial smear?2) Summarize the “fundamental theory” of simple staining. hint: what scientific property allows the dyes t bind the bacterial cell wall? Read More »

12. Assume that the diameter of a biceps muscle is 4 cm A. How long would it take O2 to diffuse from the surface of the muscle to its interior if its diffusion coefficient was equal to that in water, D 1.78 X 10 cm s? B. Each muscle fiber generally contacts several capillaries. If the muscle fiber is 50 μm in diameter, how long would it take O2 to dif- fuse to its interior, given the same diffusion coefficient as in part A?

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EXPERT ANSWER The time taken by the gas can be calculated by using t= x​​​​​​2 /2D Here x is distance travelled and D is diffusion coefficient Here in this problem they are 4 and 1.78 × 10-5 t = 16 /2(1.78× 10-5) = 16/ 3.56× 2 ×10-5 = 16/ 7.12×10-5 = 16× 105 / 7.12 = 3.88× …

12. Assume that the diameter of a biceps muscle is 4 cm A. How long would it take O2 to diffuse from the surface of the muscle to its interior if its diffusion coefficient was equal to that in water, D 1.78 X 10 cm s? B. Each muscle fiber generally contacts several capillaries. If the muscle fiber is 50 μm in diameter, how long would it take O2 to dif- fuse to its interior, given the same diffusion coefficient as in part A? Read More »

Nutrient Broth Cultures B. cereus (03) E. coli (11) M. luteus (15) P.aeruginosa (18) Tocculent Sediment Pellicle. Pellicke 1. Review Questions: 1. Why is it important to determine colony/cultural characteristics? It is important to determine colony cultural characteriscs because is going to help us to make an educated guess about the identity Of bacteria 2. What are the most common colony shapes and margins? Do you see anything unique? Colony shapes circular, irregular, filamentous, rhizoid, punctiform. colony margins: entire, ondulate lobate, filamentous, Curled, scalloped. 3. How did your own observations compare with the colony morphologies of another bacterial species? What are the similarities, what are the differences? 4. Select a colony and describe its characteristics, shapes, color, pigment etc. Colony cultural Characteristics of selected Bacteria Experiment 11 Observations and Results: Nutrient Agar Plate Cultures B.cereus (03) E. coli (11) M. luteus (15) P.aeruginosa (18) Bacterial Species Shape Margin Elevation O pacity B.cereus (03) E. coli (11) M. luteus (15) Irregular undulate raised Opaque eircular Entire Raised Beige circular Entire convex Yellow circular undulate umbanate Translucent or diffusible green P.aeruginosa (18) Nutrient Agar Slant Cultures ws B.cereus (03) E. coli (11) M. luteus (15) P.aeruginosa (18) Effuse/ Diffuse – Echimulate Beaded Echinulate – Dirty white (separated -Translucent Colonies) Experiment 11 Colony/cultural Characteristics of selected Bacteria 83 – yellow

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EXPERT ANSWER 3. m.letus – gram positive e.coli- gram negative stained with HI and orange green- conjugated WGA- M. letus gives fluorescences image while e.coli give same image with phase contrast microscopy. 4. e.coli colonies color: off-white, dry in texture, with astedy growth pattern,no pigment , but change color when trasnformed by a plsmid.

Preparation of a bacteria smear and the simple stain technique

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1) Identify the steps taken in the preparation of a bacterial smear to prevent contamination of the culture and yourself working with a bacterial smear? 2) Summarize the “fundamental theory” of simple staining. hint: what scientific property allows the dyes t bind the bacterial cell wall? 3) What would happen if you placed a large …

Preparation of a bacteria smear and the simple stain technique Read More »

Worksheet for biochemistry lab 436B experiment 5.2 – DUE AT THE START OF LAB NEXT WEEK-N ov4-8 For this lab, you will need to make a purification table. This table will be used to track the relative purity of your enzyme through the steps of purification. Below is an example of a purification table (adapted from the text book: Chapter 3, problem #15). Complete the table using the steps below (A-C) and answer the 3 following questions on the worksheet Enzyme Activity % yield (activity units) Specific Activity Purification (activity units /mg protein) Procedure Total Protein (mg) factor Crude extract 20,000 4,000,000 100 AMSO4 precipitation 5,000 3,000,000 lon Exchange 200 800,000 Chromatography Size Exclusion 45 750,000 Chromatography Table 1. Purifica tion Table for an enzyme. A. Calculate % yield. This is based on the total amount of protein remaining after each step. For example, your yield after the AmSOa precipitation step is (5,000/20,000)*100. Do this for each step. Notice we are considering total protein here, which includes all of the protein from the crude extract. So, if our yield of total protein goes down, that is not necessarily a bad thing so long as we are purifying away unwanted proteins and retaining our protein of interest. Calculate Specific Activity. Specific activity is the enzyme activity of the fraction normalized for the amount of protein present. The units for enzyme activity is “activity units”/mg total protein. B. Calculate the purification factor. The purification factor is calculated for each step by taking the ratio of the specific activity at that step to the initial specific activity (of the crude extract). The purification factor of the crude extract is set to 1 (not purified). Subsequent purification steps, if they are successful, should result in purification factors greater than 1, increasing substantially each time C. 1. Why is specific activity useful instead of just monitoring % yield after each purifications step? Examining your results from table 1, how might you change this purification scheme if you had to do it again? 2. 3. Based on the protocol in the manual, which method will we use to quantify protein con centration? mportant considerations and calculations for experiment 5.2: In exp. 5.2, we will use affinity purification to purify the B-galactosidase enzyme from e. coli (strain 3.300). The column chromatography step will re sult in several fractions that will have to be assayed for activity. You will collect 20 elution fractions of 0.5ml each. All fractions will be quickly screened (we will discuss how to do this in class), then your most active fractions (and the crude extract) will be used to calculate activity: Your activity reactions will be set up this way: 0.01 ml purified enzyme (from affinity step or crude) 0.50 ml ONPG (substrate) 2.00 ml Z-buffer 2.61 ml total volume The reactions will be run for exactly 10 min at room temp, then quenched by adding 0.5ml Na2COs We will then calculate activity: The substrate, ONPG, is cleaved by B-galactosidase to produce ONP. To quantitate this activity, we will use the Beer-Lambert law. The extinction coefficient for ONP is 18.6 mM1 cm. This can be converted into units of ml/HM * cm2; E 18.6 L/1 mM * 1 mM/10 uM * 103 ml/ 1 L = 18.6 ml/uM * cm1 Using this value of E, you can calculate activity units by first solving the Beer Lambert law, for some value of A (420 nm) which is found by running the enzyme reaction (above). Units of C should be in uM/ml “Activity units” (in uM/min) are found by multiplying ONP concentration (C) * (volume of assay)/time Enzyme Activity (this is back-calculating for the way it was when it was purified and before it was set up in the assay condition) can be calculated by Enzyme Activity (in activity units/ml) Activity units (volume of purified enzyme used in the assay) Specific Activity (in activity units/mg protein) Enzyme activity /protein concentration (mgs/ml) In addition, Total Activity can be calculated by multiplying the Enzyme Activity by the volume of the fraction. This gives you the total activity in the fraction. For example, total activity of the crude extract can be calculated by multiplying Enzyme activity of the crude extract by the volume of the crude extract that you started the purification with (1ml) IMPORTANT: When you make your Purification Table for Report 5.2, be sure to include: Total protein, Enzyme Activity, Specific Activity, Total Activity, % yield, and purification factor for crude extract and your purified fraction(s)

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2. Describe osmosis as a special case of diffusion. Distinguish between osmotic pressure and osmotic potential. 4. Explain why osmosis is, indirectly, an energy-dependent process in plants. 6. Can you suggest an important role for turgor in the plant?

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EXPERT ANSWER Answer- 2. Osmosis is the net movement of water across a semi-permeable membrane in order to achieve even solute concentrations on either side of the membrane.– same general theory as diffusion but osmosis relates specifically to water– semi-permeable membrane means the membrane allows some materials (water etc) to pass through the membrane but …

2. Describe osmosis as a special case of diffusion. Distinguish between osmotic pressure and osmotic potential. 4. Explain why osmosis is, indirectly, an energy-dependent process in plants. 6. Can you suggest an important role for turgor in the plant? Read More »

I have a research paper about HIV. I need good articles and where i find them to satisfy my research paper. the research should include the following:

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a. the manner in which the disease is transmitted (oral-fecal route, inhalation, casual contact, sexual contact, vector-transmitted ex. Tick, mosquito, kissing bug, Tsetse fly, blackfly, snail, etc.,) b. as well as the causative agent (bacteria, virus, worm, protozoan, prion). You should also discuss a brief history of the disease (including the infectious part of the …

I have a research paper about HIV. I need good articles and where i find them to satisfy my research paper. the research should include the following: Read More »