Biology 100 Winter 2021 NAME: _____________________________
Highline College
Evidence-Based Model 03 (Final Exam) How does HIV drug resistance happen?
Scientists use explanatory models in order to be able to connect a series of ideas to explain how a natural phenomenon might work. Their explanation includes the available evidence and existing scientific knowledge up to that time. A model can then be tested and revised, if necessary, as new information is gained.
In this model you will concentrate on telling a story of how HIV drug resistance happens. A story flows from a beginning, a middle, and an end. This story will be mostly a picture book story supported by words when necessary to help explain your point. The objective of this exercise is to help you to learn how populations of organisms change in response to their environment by natural selection.
This type of story is called an explanatory model, where you explain how you think a natural phenomenon works through an evidence-based explanation (or story). Your evidence, in this instance, is the information from your observations, measurements, and reliable resources from class, your labs, and your text.
OK, so lets get started! Here is a checklist of the following terms and concepts that you should include in your story of how antibiotics might work.
Checklist for Explanatory Model of Natural selection of HIV drug resistance in a population of HIV viruses
First, there was an infection.
1) Story starts with explanation of where HIV drug resistance is taking place.
then make clear why the next part of the story comes next.
2) Draw a diagram and explain the life cycle of the HIV virus making sure to include the 3 HIV enzymes:
q reverse transcriptase
q integrase
q protease
q then make clear why the next part of the story comes next.
3) Draw a diagram and explain how drugs work by:
q competitive inhibition
q noncompetitive inhibition
q then make clear why the next part of the comes next.
4) Explain how reverse transcriptase causes the presence of pre-existing variations. Include a description of the different types of mutations:
q single base pair mutation
o silent
o missense
o nonsense
q insertions and deletions
o reading frame
q then make clear why the next part of the comes next.
5) Explain how a random mutation could be resistant to an anti-HIV drug.
then make clear why the next part of the comes next.
6) Explain whether the drug causes the presence of that random mutation or reverse transcriptase causes it.
then make clear why the next part of the comes next.
7) Explain how the drug selects for the random mutation producing a population of HIV-drug resistant viruses.
then make clear why the next part of the comes next.
8) How the HIV population changes over time:
Draw your Time 0/Time 1/Time 2 diagram of HIV drug resistance. Make a key to clearly label each type of virus. Time 0 is the population of HIV viruses BEFORE drug is taken, Time 1 is when the drug is working, and Time 2 is much later when the same drug is now no longer working HIV is resistant to the drug.
then make clear why the next part of the comes next.
9) Write a short paragraph that summarizes how resistance to anti-HIV drugs can occur in a population of HIV viruses through natural selection of a drug-resistant variation. This paragraph serves as a summary (backed up by evidence!) of your entire model.
q Make sure you include all of the following five key concepts in your explanation.
o Population
o Pre-existing genetic variation (random)
o Environmental pressure/selection/ selected (not random)
o Heritable traits/ inheritance/ inherited
o Adaptation/ adapted
q Also make sure to include a detailed description of how other viruses (like SARS-CoV-2 or influenza) change over time from your SimBio lab.
Level of Evidence-Based Explanation:
Level 1 Level 2 Level 3
(5 points) (8 points) (10 points)
Level of Evidence-Based Explanation rubric:
Level 1
Level 2
Level 3
- Student describes what happens in each part of the model without linking them together to explain how or why a population of HIV viruses evolves resistance to an anti-HIV drug.
- Student describes, summarizes, or restates each part of the checklist without making a connection to full causal story.
- No references to established theories or evidence from lab or the text are used.
- Student describes how or partial why a population of HIV viruses evolves resistance to an anti-HIV drug.
- Student links together some parts of the model but not all.
- Student addresses theoretical components tangentially (non-specifically) or does not reference evidence from lab and the text in their explanation.
- Student explains a population of HIV viruses evolves resistance to an anti-HIV drug
- Student can trace a full causal story for why a phenomenon occurred. This is well supported by diagrams in the model.
- Student uses powerful science ideas like the theory of natural selection random genetic mutations, as well as references to evidence from lab and the text, to explain observable events.
10) References: Include APA7 references for
your textbook sources, the SimBio lab, and any other outside sources that you used
(dont accidently plagiarize something!!)
