MIT Biology Department 7.012: Introductory Biology-Fall 2004 Instructors: Professor Eric Lander, Professor Robert A Weinberg, Dr. Claudette Gardel Name Section Solutions to 7.012 Problem set 6 Question 1 The hematopoietic system of mammals is a convenient model to use to study development and differentiation. The bone marrow transplantation experiment discussed in lecture indicates that stem cells are more than a figment of some biologist's fertile imagination. a) Briefly outline the experiment A mouse is lethally irradiated, killing all bone marrow cells. Bone marrow cells are obtained from a non-irradiated donor mouse. The donor nouse marrow is injected into the irradiated mouse. The injected cells save the irradiated mouse from death b)Explain how the experiment proves that stem cells exist in the bone marrow The number of injected marrow cells is small, and not all the blood cell types are represented. The injected cells divide and replace all the cells and cell types that were killed by irradiation Use the figure below as an aid for the following questions Progenitor Pluripotent Committed Committed Stem Cel Stem Cell Stem Cell Monocvte Macrophage Basophil Eosinophil Neutrophil Red blood cell Platelets 7012Fall2003Name:___________________________________ Section:_____ 7.012 Fall 2003 1 Solutions to 7.012 Problem Set 6 Question 1 The hematopoietic system of mammals is a convenient model to use to study development and differentiation. The bone marrow transplantation experiment discussed in lecture indicates that stem cells are more than a figment of some biologist's fertile imagination. a) Briefly outline the experiment. A mouse is lethally irradiated, killing all bone marrow cells. Bone marrow cells are obtained from a non-irradiated donor mouse. The donor mouse marrow is injected into the irradiated mouse. The injected cells save the irradiated mouse from death. b) Explain how the experiment proves that stem cells exist in the bone marrow. The number of injected marrow cells is small, and not all the blood cell types are represented. The injected cells divide and replace all the cells and cell types that were killed by irradiation. Use the figure below as an aid for the following questions. Common Progenitor Cell Committed Stem Cell Pluripotent Stem Cell Committed Stem Cell Committed Stem Cell Committed Stem Cell Platelets Megakaryocyte Red Blood Cell Basophil Eosinophil Neutrophil Monocyte Macrophage B Lymphocytes T Lymphocytes Lymphoblast or MIT Biology Department 7.012: Introductory Biology - Fall 2004 Instructors: Professor Eric Lander, Professor Robert A. Weinberg, Dr. Claudette Gardel