Asthma is commonly treated with an inhaled corticosteroid (ICS) and long-acting β2-agonist (LABA), whereas COPD is often treated with a long-acting β2-agonist (LABA) and long-acting muscarinic antagonist (LAMA). Explain why the preferred maintenance treatment differs between these two obstructive lung diseases. Relate your answer to the underlying pathophysiology.

Most traits are quantitative, meaning they exhibit continuous variation in a population. This is exemplified in the graph below for beak width in a population of finches. Continuous variation in a trait like beak width suggests that the trait is determined by…

Use the table below to transcribe and translate the following DNA template strand and identify the final polypeptide strand. DNA: TACGGGGGTCCCTTGGCA

Most traits are quantitative, meaning they exhibit continuous variation in a population. This is exemplified in the graph below for body weight in a population of finches. Continuous variation in a trait like body weight suggests that the trait is determined by…

The diploid chromosome number of the yellow fever mosquito, Aedes aegypti, is 6 (2n = 6). After completing meiosis, how many chromosomes would you find in each mosquito gamete?

The APC gene is a tumor-suppressor gene that regulates the cell cycle. Mutations in APC are associated with the development of colorectal cancer. As a tumor-suppressor gene, how do you expect mutations in APC to disrupt the cell cycle?

A research team isolated a novel single-celled organism from a deep-sea hydrothermal vent and analyzed its genome. They observed that the organism’s genetic material is located in the cytoplasm rather than in a nucleus, consists of a single circular chromosome, and has a high gene density with very little non-coding DNA. Based on these characteristics, which type of organism did the team isolate?

Identical twins have the same genotype, but one twin grows up to be taller than the other. Which statement best explains how this can happen?

To make copies of specific DNA sequences in the lab, scientists use polymerase chain reaction (PCR). During PCR, heat is used to “unzip” the two strands that comprise the DNA molecule. PCR mimics DNA replication in some ways, but not in how the two strands are pulled apart. How are the two strands of DNA unzipped during DNA replication in the cell?

In a clinical trial for hemophilia B, a bleeding disorder caused by mutations in the gene for clotting factor IX, researchers evaluated an AAV-vector gene therapy delivering a functional factor IX gene. Three cohort groups received a single intravenous infusion at different doses (low, medium, and high), while a fourth cohort received a placebo infusion. After one year, researchers measured factor IX activity in the blood and recorded the number of bleeding episodes for each participant. What is the independent variable in this experiment?