MIT Biology Department 7.012: Introductory Biology-Fall 2004 Instructors: Professor Eric Lander, Professor Robert A. Weinberg, Dr. Claudette Gardel Solutions to 7.012 Problem set 1 Question 1 Bob, a student taking 7.012, looks at a long-standing puddle outside his dorm window Curious as to what was growing in the cloudy water, he takes a sample to his TA, Brad Student. He wanted to know whether the organisms in the sample were prokaryotic or eukaryotic a)Give an example of a prokaryotic and a eukaryotic organism Eu All bacteria Yeast, fungi, any animial or plant b)Using a light microscope, how could he tell the difference between a prokaryotic organism and a eukaryotic one? The resolution of the light microscope would allow you to see if the cell had a true nucleus or organelles A cell with a true nucleus and organelles would be eukaryotic. You could also determine size, but that may not be suficient to establish whether a cell is prokaryotic or eukaryotic c)What additional differences exist between prokaryotic and eukaryotic organisms? Any answer from above also fine here. In addition prokaryotic and eukaryotic organisms differ at thhe DNA level. Eukaryotes have more complex genones than prokaryotes do Question 2 a new startup company hires you to help with their product development. your task is to find a protein that interacts with a polysaccharide a) You find a large protein that has a single binding site for the polysaccharide cellulose Which amino acids might you expect to find in the binding pocket of the protein? What is the strongest type of interaction possible between these amino acids and the cellulose? Cellulose is a polymer of glucose and as such has many free hydroxyl groups. These hydroxyl groups could make hydrogen bonds with any of the charged or uncharged polar amino acids. You may expect serine, threonine, asparigine, glutamine, tyrosine, arginine, histidine, lysine, aspartic acid or glutanic acid to be associated with the binding of cellulose 7012Fall20037.012 Fall 2003 1 Solutions to 7.012 Problem Set 1 Question 1 Bob, a student taking 7.012, looks at a long-standing puddle outside his dorm window. Curious as to what was growing in the cloudy water, he takes a sample to his TA, Brad Student. He wanted to know whether the organisms in the sample were prokaryotic or eukaryotic. a) Give an example of a prokaryotic and a eukaryotic organism. Prokaryotic: Eukaryotic: All bacteria Yeast, fungi, any animial or plant b) Using a light microscope, how could he tell the difference between a prokaryotic organism and a eukaryotic one? The resolution of the light microscope would allow you to see if the cell had a true nucleus or organelles. A cell with a true nucleus and organelles would be eukaryotic. You could also determine size, but that may not be sufficient to establish whether a cell is prokaryotic or eukaryotic. c) What additional differences exist between prokaryotic and eukaryotic organisms? Any answer from above also fine here. In addition, prokaryotic and eukaryotic organisms differ at the DNA level. Eukaryotes have more complex genomes than prokaryotes do. Question 2 A new startup company hires you to help with their product development. Your task is to find a protein that interacts with a polysaccharide. a) You find a large protein that has a single binding site for the polysaccharide cellulose. Which amino acids might you expect to find in the binding pocket of the protein? What is the strongest type of interaction possible between these amino acids and the cellulose? Cellulose is a polymer of glucose and as such has many free hydroxyl groups. These hydroxyl groups could make hydrogen bonds with any of the charged or uncharged polar amino acids. You may expect serine, threonine, asparigine, glutamine, tyrosine, arginine, histidine, lysine, aspartic acid or glutamic acid to be associated with the binding of cellulose. MIT Biology Department 7.012: Introductory Biology - Fall 2004 Instructors: Professor Eric Lander, Professor Robert A. Weinberg, Dr. Claudette Gardel