Molecular and Cellular Biology

The secondary field in Molecular and Cellular Biology (MCB) is intended for students with an interest in the life sciences, particularly in the study of biological processes based on the investigation of molecules and their interactions in the context of cells and tissues. The cell is the fundamental unit of all living things and is therefore an ideal framework for integrating one's understanding of the structure and chemistry of macromolecules with their higher-order organization and behavior in a living context. Students pursuing the MCB secondary field gain a solid foundation by completing a set of three courses within introductory life sciences courses and intermediate courses in the MCB department. To deepen their understanding of the discipline, students will then enroll in two additional MCB courses of their choosing. The choice of these courses, which should be made with the guidance of a concentration adviser, will allow students to explore specific sub-fields in MCB, such as biochemistry, microbiology, immunology, virology, neurobiology, and molecular medicine. Students are also encouraged to get involved in research. The secondary field is designed for students who desire a broad yet rigorous introduction to the field and may be appropriate for students with diverse career interests, including (but certainly not limited to) applied mathematics, statistics, computer science, economics, government, health policy, business, and journalism. 

REQUIREMENTS: 5 courses (20 credits) 

  1. Three or four introductory or intermediate courses as follows: 
    1. One or two integrated introductory courses in the life sciences: 
      1. Life Sciences 1a: Chemistry, Molecular Biology, and Cell Biology (or Life and Physical Sciences A) 
      2. Life Sciences 1b: Genetics, Genomics, and Evolution 
    2. One or two intermediate courses in molecular and cellular biology: 
      1. MCB 60, MCB 63, MCB 64, MCB 65, MCB 68 MCB 80, or MCB 81. 
  2. Complete the remainder of requirements from advanced courses in MCB. 
    1. MCB 100-level courses 
    2. One of these courses can be a research course (MCB 91 or MCB 100/LS 100) 


  • LS 1a and LS 1b (or LS 50), as well as MCB 60, are foundational courses highly recommended for all students. 
  • Students should consult the concentration adviser for advice on 100-level course selection. Research courses are encouraged for students interested in integrating a research experience into their plan of study. 
  • Students who take LS 50 will be credited for LS 1a, LS 1b, and a research course. They can thus fulfill the secondary field requirements by completing two intermediate courses, or one intermediate course and one MCB 100-level course. 


To count for credit towards the secondary field, the five courses must be taken for a letter grade. Freshman Seminars will not count towards the secondary field. Students working in a research laboratory as part of a study abroad program can petition to have that research experience count as an advanced course towards the secondary field, and some Harvard Summer School Courses can count for credit towards the secondary field with preapproval. Students should contact the MCB concentration adviser, Dr. Dominic Mao (, for more information on counting Harvard Summer School courses and research conducted as part of a study abroad program for the secondary field in MCB. Students pursuing a secondary field in MCB will not be given preferential access to limited enrollment courses. We do not anticipate that courses required for the secondary field will be over-enrolled. 

The MCB secondary field is not open to students concentrating in Chemical and Physical Biology, Human Developmental and Regenerative Biology, or Neurobiology, given similarities in the content and skills developed within these concentrations and current policy with respect to counting courses for concentration and secondary fields. 


For additional information, students interested in pursuing the MCB secondary field may contact the MCB concentration adviser, Dr. Dominic Mao ( Students are encouraged to meet with the concentration adviser as needed, particularly upon completion of the introductory and intermediate courses to select appropriate advanced courses. Students intending to pursue the MCB secondary field in should notify the department using the secondary fields web tool. Upon completion of the secondary field requirements, students need to meet with the concentration adviser to confirm that the courses they have taken count for credit towards the MCB secondary field.