Homework Packet 13 due tomorrow Warm up: If the DNA strand is ATGCCAAT, what is the corresponding mRNA strand? Flush: Do you think we will have a snow day Monday? Homework Packet 13 due tomorrow

What is going on in the video? https://www.youtube.com/watch?v=plVk4NVIUh8

Antibiotic Resistance A bacterium is labeled as ‘resistant’ if it is unable to be killed by one or more antibiotics This is a growing public health problem

How does this relate to natural selection? Bacteria evolve just like anything else and their antibiotic resistance is a result of natural selection A random mutation occurs, give one bacterium genes that make it resistant to an antibiotic That one bacterium will survive better, and reproduce more, passing those resistant genes on

Natural Selection and Antibiotic Resistance

Steps of Antibiotic Resistance 1. A population of bacteria replicate quickly, and naturally, mutations occur. Some of those mutations may code for proteins that create a resistant bacteria 2. Once antibacterial products are given to the bacteria, the resistant bacteria have a strong advantage 3. The resistant bacteria survive the antibiotics, reproduce, and pass their resistant genes on 4. Over time, the antibiotic will kill off ‘sensitive’ bacteria, leaving only resistant bacteria to remain

Even bigger worry… Bacteria can share their DNA with other bacteria cells through a process called conjugation This means, if one bacteria cell in your body is resistant, it can potential share those resistant genes to millions of other of bacteria Even bacteria of a different species

Common Resistant Bacterial Diseases MRSA (staph infections) Methicillin resistant staphylococcus aureus VRSA Vancomyocin resistant staphylococcus aureus Vancomyocin used to be the strongest/last resort antibiotic These infections are very hard to treat C. diff (clostridium difficile) A common nosocomial infection (hospital-acquired)

Why is this a problem now? 1. Antibiotics in agriculture 2. Misuse of antibiotics 3. Overuse of antibiotics 4. Greater exposure to antibacterial products 5. Little financial incentive to make more antibiotics

How does overuse led to antibiotic resistance? The more the bacteria on a surface or on your body are exposed to an antibiotic, the greater the selection pressure is to carry resistant genes If a population of bacteria is never exposed to antibiotics, then being resistant gives them no advantage The more antibiotic exposure you have, the more times you are killing off the ‘weaker/sensitive’ bacteria cells, and allowing the resistance ones to grow

What about antibacterial soap? Directions: read and annotate the article from the FDA. Then, answer the questions below. Reading Questions: 1. What two specific active ingredients did the FDA decide can no longer be marketed? 2. Explain the reasoning that the text gives for banning those ingredients. 3. What types of products does this ban not include right now? Why is that? 4. Describe one possible negative health effect of triclosan? 5. What does the FDA still need to investigate further about this issue? 6. What, as a consumer, should you do? Why?