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Indiana University Bloomington

Department of Biology

Undergraduate Studies

Microbiology Majors

The diversity of plants and animals that marvel our eyes is a mere twig on the tree of life. The vast majority of life is too small to see with the naked eye. And yet, the unseen microbial world accounts for most of the Earth’s biomass. Most of the cells in and on our own bodies are not our own—they are microbes. Microbes are crucial players in global cycles, removing as much greenhouse gas from the atmosphere as all plant life on Earth.

Then consider that cellular microbes—bacteria, archaea, and fungi—are greatly outnumbered by viruses. The viruses in the oceans alone are estimated to weigh as much as 75-million blue whales and, if strung together, could crisscross our galaxy 100 times (Suttle. 2005. Nature.).

What are all of these microbes and what are they doing? The Microbiology program provides students with fundamental knowledge and skills to approach and address these questions. Core lectures and hands-on laboratory experiences introduce students to the form, function, genetics, and evolution of diverse microorganisms with an emphasis on bacteria and viruses. Students learn how diverse microbes positively and negatively impact our health, society, and the environment. Students also use the scientific process to interpret, evaluate, and communicate biological information as well as to identify and address open questions in microbiology. Students are encouraged to pursue independent research projects under the mentorship of research faculty in the department.

Courses are offered in microbial ecology, microbial genetics, medical microbiology, cellular biology, virology, and molecular biology. In addition, general coursework includes inorganic and organic chemistry and calculus, as well as courses in the humanities, social science, English composition and foreign language. Students may supplement their degrees with minors or certificates in areas such as business, environmental science, animal behavior, and psychology. Outstanding students are encouraged to fulfill the requirements for an honors degree.

Graduates of the Microbiology program are well situated for a wide range of careers in health-related professions, biological and medical research, and biotechnology fields—including pharmaceutical and biofuel development, laboratory quality control and diagnostics, public and global health, environmental and science policy, law and intellectual property, business, education, and science writing. Many of our graduates are admitted to medical school, dental school, and graduate programs. Two-thirds of the department's graduates are available for entry-level positions. In recent years, the average GPA for Department of Biology graduates has been 3.22, while the average GPA for Microbiology B.S. majors has been 3.28. Each year at least 50 departmental graduates are elected to Phi Beta Kappa.

Microbiology Major (B.S.)

(from 2015-16 College of Arts & Sciences Bulletin)
For a detailed description of the Microbiology B.S. major, please review the Microbiology B.S. Major Guide.


The B.S. Degree in Microbiology trains students who wish to pursue careers as professional microbiologists in health, environmental, governmental, or industrial laboratories, and provides the foundation for professional or graduate training in microbiology and related fields.

Required Courses

Students must complete the following Foundations, Intensive Writing, Mathematics, Foreign Language, Critical Approaches, and Breadth of Inquiry, and Public Oral Communication requirements:

  • Writing, same as for B.A. degree (English CompositionIntensive Writing).
  • Mathematics, fulfilled by major.
  • Foreign language, three semesters in the same language or equivalent proficiency.
  • One Critical Approaches course.
  • Arts and humanities, two courses.
  • Social and historical studies, two courses.
  • Natural and mathematical sciences, fulfilled by major.
  • One course in Public Oral Communication.
  • Culture studies courses are not required.
Major Requirements

Students must complete the following:

  • Biology L112 and L211.
  • Microbiology M250 and M255 (or M250 and M315).
  • Microbiology M350, M360, and M480.
  • Two of the following lab courses: M435, M445, M465, M485, or BIOT T315.
  • One of the following lecture courses: M430, M440, or M460.
  • Two of the following additional lecture courses: M430, M440, M460, M375, M416, B351, L312, L321, L472, or BIOT T310. Courses used to fulfill requirement 5 above will not apply to requirement 6.
  • CHEM C117-C127, C341, C342, and C343. Students planning to enter a professional school should check to see what additional courses they will need.
  • PHYS P201-P202 or P221-P222.
  • One of the following statistics courses: MATH K310, PSY K300 or K310, LAMP L316, STAT S300 or S303, or SPEA K300. (Note that although SPEA K300 fulfills the statistics requirement, it does not count toward College of Arts and Sciences credit hours.)
  • MATH M211 or M215 (or M119 and M120, or MV119 and M120) or an approved mathematics course.

Students must also complete the requirements and procedures listed in this Bulletin under "CASE Credit Hour and Residency Requirements."


Because chemistry is a prerequisite for many upper-level microbiology courses, students are urged to begin chemistry as soon as possible. Students should consult the Biology advising office to plan a coherent program.

Please use the Undergraduate Academic Bulletin that was in effect when you matriculated into Indiana University Bloomington as a degree-seeking student. The requirements outlined in the Bulletin in effect at the time of your matriculation will remain constant throughout your time in the Biology Department, assuming you graduate within eight years. Degree requirements may change significantly from year to year, so it’s very important that you refer to the correct Bulletin. If you are uncertain which Bulletin governs your undergraduate career, please consult a Biology advisor by emailing, calling (812) 855-3810, or making an advising appointment with any Biology advisor. 

See also Biology Major (B.A.) »

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