Natural Selection Antibiotic Resistance What is Antibiotic Resistance
Natural Selection Antibiotic Resistance
What is Antibiotic Resistance? • Watch the Video Clip about tuberculosis in Russian prisons • Why is the Russian prison system considered “ground zero” in the fight against TB?
Virus vs. Bacteria • A virus is non-living, does not have organelles, and needs a host cell to reproduce • Bacteria are alive, have ribosomes, and can reproduce on their own
Antibiotics • Substances that kill disease causing bacteria • Fifty years ago, scientists thought that antibiotics had eradicated certain bacterial infections • Now, we are seeing an increase in infectious disease
What is happening? • When antibiotics are used, MOST of the bacteria are killed. • Some of the bacteria have mutated and can survive even when the antibiotic is taken • They are “resistant” to the antibiotic
Mutation Review • How does a mutation occur? – The DNA sequence is changed in some way – An error occurs during • Replication • Transcription • Translation – When the bacteria reproduce, this mutation is passed on to the new bacteria
Natural Selection • The “resistant” bacteria are the only bacteria to survive after using antibiotics • They reproduce rapidly! • This creates an entire colony of resistant bacteria that will not be killed by antibiotics
• Natural Selection means the survival of the “fittest” • What does “fittest” mean? – Those organisms that can survive and reproduce – Adapted to the environment • The resistant bacteria are the “fittest” and survive and reproduce
• If the weakest bacteria are killed first, and you stop taking your antibiotics after five days of a ten day course, what do you predict will happen to the population of bacteria in your body?
Antibiotic Resistance Activity • Follow the procedure on your lab paper to simulate what happens when antibiotics are not taken as prescribed • Record your data in Table 1 and graph the data when you are finished • Complete the analysis questions in your lab notebook
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