Question

Biosurfactant activity can be measured by absorption of 540nm light. What is true of biosurfactant assays on a mixture of oil and water? ELLELE Increased biosurfactant activity causes a decrease in absorption of 540nm light Droplet sizes become bigger and bigger with more biosurfactant activity Droplets are mostly formed in the water layer None of the statements are true Question 3 (1 point) How does the zone of inhibition vary in disk-diffusion antibacterial tests? Different antibiotics at equal concentration will have the same diameter for their zones of inhibition The same antibiotic at different concentrations will have the same zone of inhibition diameter Zones of inhibition is not depend on the species of bacteria tested None of the above

Answer 1

1. The answer is none of the statements are true as absorbance increases in presence of biosurfactant at 540nm. Greater the biosurfactant activity, better emulsion formation so smaller the droplet size and droplets can be formed in water or oil phase depending on the type of emusion formed. It could be oil in ater or ater in oil. hence these options are wrong.

2. Zone of inhibition determines the activity of a particular antibiotic against a particular strain of bacteria. More efficient the antibiotic is against the strain, greater the diameter of the zone of inhibition. Since different antibiotic might have different effects on a bacteria zone of inhibition diameter is not same for same concentrations of different antibiotics, different concentration of the same antibiotic also give different zone of inhibitions, generally ith increase in concentration diameter increases.

3. The concentration of DNA is highest in sample C as according to beer lambert's la absorbance is directly proportional to concentration.The maximum absorbance of DNA is at 260nm and since Sample C has highest OD at 260nm it has the highest concentration of DNA. Also A260/A280 gives the amount of protein contamination. Higher the A260/A280 greater the DNA concentration and lesser the protein impurity. Again here sample C has the highest value indicating it has highest DNA concentration.