read Harper and Brand 1993, then respond in writing to the questions
1. Describe the cellular mechanism by which thyroid function influences cellular respiration rate. What
happens in a respiring cell when hypothyroid conditions occur? What about hyperthyroid conditions? How
do the authors intend to improve understanding of thyroid hormones and their effect on cellular respiration?
2. Without becoming mired in the mathematics involved, discuss the methodological approaches employed
by the authors. How did they estimate respiration rate in hepatocytes? (What’s a hepatocyte?) How did
they estimate ATP content? What did the authors use radioactive isotopes for in the study? What did they
use electron microscopy for?
3. The authors use the arcane notation ‘ΔΨm’ to refer to mitochondrial membrane potential, which is
displayed on the y-axis of nearly every graph presented. Briefly summarize the authors’ findings with
regard to mitochondrial membrane potential in rats of varying thyroid function. How do the differences
translate to other aspects of respiratory function at the cellular level?
4. A goal of this course is to improve your technical literacy in biology. Indicate how information presented
in class (via lecture, lab, or textbook) contributed to your comprehension of the assigned article.
