7.012: Introductory Biology-Fall 2004 Instructors: Professor Eric Lander, Professor Robert A Weinberg, Dr. Claudette Gardel Friday 11/12/04 7.012 Quiz 3 Answers A>85 18% of test takers b 72-84 41% of test takers c 60-71 23% of test takers D 50-59 11.4% of test takers F<58 6.6% of test takers REGRADE Requests with attached notes describing the problem due by November 24mnoon Question Value Score 25 2 19 3 15 15 5 26 100
Friday 11/12/04 7.012 Quiz 3 Answers A > 85 18% of test takers B 72-84 41% of test takers C 60-71 23% of test takers D 50-59 11.4% of test takers F < 58 6.6% of test takers REGRADE Requests with attached notes describing the problem due by November 24th noon. Question Value Score 1 25 2 19 3 15 4 15 5 26 100 MIT Biology Department 7.012: Introductory Biology - Fall 2004 Instructors: Professor Eric Lander, Professor Robert A. Weinberg, Dr. Claudette Gardel��
Question 1 a)Circle whether the following antigens can be specifically and directly recognized by Antibodies and/or T cell receptors. 9 points-Graded horizontally. 1 Point each row, both have to be correct to get the point. The bottom row is 2 points an be Can b recognized by recognized by Antigen Antibodies cell receptors NO yES No\ Lipids ES NO yES NO Carbohydrates yES NO yES No Bacterial surface proteins yES NO yES No Viral capsids yES NO yES NO 3-Dimensional polypep otide folds in native proteins yES NO yES NO Linear oligopeptides yES NO yES Non -self MHc Class I/II molec yES NO ES NO MHC Class I/II molecules complexed with linear lse. 7 points t F i)B cells can generate higher affinity antibodies for antigens over time F ii)T cells can generate higher affinity T cell receptors for antigens over time T F ii)A single B cell might make antibodies that recognize many different epitopes I capsid pre F iv) Each of us is born with hundreds of genes each of which encodes an antibody to recognize a specific virus F v) Macrophages envelope and digest foreign antigens nonspecifically T F vi) T-cell receptors are membrane bound and thus can signal the T cell to ingest T F vi) Cytotoxic T cells can activate B cells to proliferate
Question 1 a) Circle whether the following antigens can be specifically and directly recognized by Antibodies and/or T cell receptors. 9 points-Graded horizontally. 1 Point each row,both have to be correct to get the point. The bottom row is 2 points. Can be Can be recognized by recognized by Antigens Antibodies T cell receptors YES NO YES NO Lipids YES NO YES NO Carbohydrates YES NO YES NO Bacterial surface proteins YES NO YES NO Viral capsids YES NO YES NO 3-Dimensional polypeptide folds in native proteins YES NO YES NO Linear oligopeptides YES NO YES NO Non-Self MHC Class I/II molecules YES NO YES NO MHC Class I/II molecules complexed with linear oligopeptides b) True or False. 7 points T F i) B cells can generate higher affinity antibodies for antigens over time. T F ii) T cells can generate higher affinity T cell receptors for antigens over time. T F iii) A single B cell might make antibodies that recognize many different epitopes on a viral capsid protein. T F iv) Each of us is born with hundreds of genes each of which encodes an antibody to recognize a specific virus. T F v) Macrophages envelope and digest foreign antigens nonspecifically. T F vi) T-cell receptors are membrane bound and thus can signal the T cell to ingest antigen. T F vii) Cytotoxic T cells can activate B cells to proliferate. 2
d)Which ONE of the following does Not provide innate immunity against pathogens? 2pts blinking macrophages ciliated cells in trachea mucous membranes low pH of stomach plasma cells lysozyme in tears skin e)Which of the following cells can you be sure CAN NoT have the same genetic content of a skin cell. For any circled, on the adjacent line, explain why in 5 words or less. 4 pts Helper T dna rearrangement of TCR_ or_VDJ rec Lung cell Macr Plasma Cell VDJ REC or somatic mutation or hypermutation or junctional diversity f) Continue the graph following the exposure to rabies virus in this laboratory mouse Concentration 10 of polio Virus antibodies Rabies virus In serum iniection of lab mouse
Name__________________________________ d) Which ONE of the following does NOT provide innate immunity against pathogens? 2pts blinking macrophages ciliated cells in trachea mucous membranes low pH of stomach plasma cells lysozyme in tears skin e) Which of the following cells can you be sure CAN NOT have the same genetic content of a skin cell. For any circled, on the adjacent line, explain why in 5 words or less. 4 pts Helper T cell ___dna rearrangement of TCR____ or ___VDJ rec.__ Lung Cell ______________________________________ Macrophage ______________________________________ Plasma Cell _____VDJ REC or somatic mutation or hypermutation or junctional diversity____ f) Continue the graph following the exposure to rabies virus in this laboratory mouse. 3 points Concentration 104 of Polio Virus antibodies in serum of lab mouse 102 Rabies virus injection Polio virus injection Time 3
Question 2 Winston, an avid cigarette smoker, detects tumors in 3 of his 6 dogs. Lucky Strike has an ear tumor, Virginia Slims has a paw tumor, and Kool has a tail tumor. Bob, a biologist friend, takes cells from each tumor as well as cheek cell samples from the dogs as controls and cultures them in Petri dishes. All of the cheek cell cultures grow as a monolayer but all of the tumor cell cultures exhibit foci a)Which ONE of the following properties do the tumor cells lack, resulting in this growth difference. 3 pts ATP hydrolysis tact inhibition G5 processing Retinoblastoma Signaling cascade b)Bob brushes up on the molecular nature of different cancer mutations. Match the following mutations to their respective phenotypes at the cellular level. 4 pts D dominar o_ Tumor Suppressor mutation m)G5 processing defective n)opportunistic o recessive p)none of these To determine the cause of each of the dogs tumors, he performs the following experiments. cheek cells isolate DNA→ (inject DNA) ear tumor cells transfection isolate DNA→ inject DNA→ wild type cell uncontrolled growth paw tumor cells isolateD→0×mtem tail transfection eDNA→ ject DNA)→> Figure by MIT OCW
Question 2 Winston, an avid cigarette smoker, detects tumors in 3 of his 6 dogs. Lucky Strike has an ear tumor, Virginia Slims has a paw tumor, and Kool has a tail tumor. Bob, a biologist friend, takes cells from each tumor as well as cheek cell samples from the dogs as controls and cultures them in Petri dishes. All of the cheek cell cultures grow as a monolayer but all of the tumor cell cultures exhibit foci. a) Which ONE of the following properties do the tumor cells lack, resulting in this growth difference.3 pts ATP hydrolysis Contact Inhibition G5 processing Retinoblastoma Signaling cascade b) Bob brushes up on the molecular nature of different cancer mutations. Match the following mutations to their respective phenotypes at the cellular level. 4 pts l) dominant ___o_ Tumor Suppressor mutation m) G5 processing defective n) opportunistic o) recessive ___l_ Oncogene mutation p) none of these To determine the cause of each of the dogs’ tumors, he performs the following experiments. cheek cells isolate DNA transfection (inject DNA) wild type cell controlled growth ear tumor cells transfection isolate DNA (inject DNA) wild type cell uncontrolled growth paw tumor cells transfection isolate DNA (inject DNA) wild type cell controlled growth tail tumor cells transfection isolate DNA (inject DNA) wild type cell uncontrolled growth Figure by MIT OCW. 4
Name c)Based on previous data, which tumor(s)has/have a mutation in a tumor suppressor gene? Circle aLL that apply 2 pts Cheek d) Based on the data above, which tumor(s)has/have a mutation resulting in an oncogene? Circle ALL that apply. 4 pts Paw Bob isolates the cells from each dish and fractionates them to isolate the membranes Bob measures the amount of phosphorylated amino acids present, using a specific antibody. See the results below Binding of Antibody Tail Specific for phosphorylated amino acids some Cheek Ear Paw Membrane fractions from Cells Bob reads that the three most likely causes for canine tumors are 1)Ras oncogene mutations 2)Mutations resulting in constitutively active tyrosine kinase receptors 3)Mutations inactivating the p53 tumor suppressor gene e)Based on the data above, match the different tumor types with the likely cancer causes listed above 6 points Ear tumor 3 Paw tumor 2 Tail tumor
Name__________________________________ c) Based on previous data, which tumor(s) has/have a mutation in a tumor suppressor gene? Circle ALL that apply. 2 pts Cheek Ear Paw Tail d) Based on the data above, which tumor(s) has/have a mutation resulting in an oncogene? Circle ALL that apply. 4 pts Cheek Ear Paw Tail Bob isolates the cells from each dish and fractionates them to isolate the membranes. Bob measures the amount of phosphorylated amino acids present, using a specific antibody. See the results below. lots Binding of Antibody –Specific for phosphorylated amino acids some Cheek Paw Tail Ear Membrane Fractions from Cells Bob reads that the three most likely causes for canine tumors are… 1) Ras oncogene mutations. 2) Mutations resulting in constitutively active tyrosine kinase receptors. 3) Mutations inactivating the p53 tumor suppressor gene. e) Based on the data above, match the different tumor types with the likely cancer causes listed above. 6 points __1___Ear tumor ___3__Paw tumor ___2__Tail tumor 5