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Small Girl, Huge Appetite

How a Small Genetic Change Can Have a Big Consequence


Author(s)

Shuangying Yu
Sciences Division
Central Piedmont Community College
shuangying.yu@cpcc.edu
Weston McNeely

University of North Carolina at Charlotte

Abstract

This “clicker case” tells the story of “Hannah,” a baby girl adopted by two loving parents who grows up with an uncontrolled appetite and develops severe early-onset obesity. Students follow Hannah’s story as she develops excessive eating early in life, which her health care team is unable to explain. A visit to obesity specialists finally reveals the underlying cause of Hannah’s obsession with food: extremely low levels of circulating leptin, a hormone that regulates appetite and body weight. It is further discovered that Hannah’s leptin deficiency is due to a mutation in the LEP gene. As the story unfolds, students first work on unit conversions and BMI calculations to practice quantitative skills as well as graph and data interpretation skills. Students then apply their knowledge of DNA transcription, translation, and protein structure to answer questions based on figures from a 2019 study on LEP mutations. The case is best suited for high school and lower-level undergraduate biology courses.


Objectives

  • Properly perform unit conversions.
  • Calculate body mass index using a provided mathematical formula and interpret data using available reference graphs.
  • Properly interpret figures from scientific publications.
  • Identify various types of DNA point mutations.
  • Apply knowledge of DNA transcription and translation to explain how a mutation may alter amino acid sequence and the 3-D structure of protein.
  • Apply knowledge of the central dogma to explain how a mutation may lead to a defective protein product and a genetic disorder that manifests as clinical conditions.

Keywords

Transcription; translation; mutation; protein structure; body mass index; BMI; leptin; obesity; central dogma

Educational Level

High school, Undergraduate lower division

Format

PDF, PowerPoint

Type / Methods

Clicker, Directed, Discussion

Language

English

Subject Headings

Biology (General)  |   Genetics / Heredity  |  


Date Posted

01/11/2022

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