Molecular Biology中国大学mooc作业答案

日期:2022-08-10 06:41:16

1. Introduction

Assignment-week 1

1、Please explain the experiment done by Frederick Griffith in 1928 which proved that DNA might be the key genetic material. Please try good academic expression.

2、Please give one example of a biological process at molecular level which shows the smartness of a living organism.

3、Please give an example of a biological process which involves forming and breaking of a weak bond under the physiological conditions present within cells.

2. Genome Structure, Chromatin, and the Nucleosome - I

Assignment-week 2

1、Why are gene densities of eukaryotic genes lower than those of prokaryotic genes?

2、Please describe the composition of human genome.

3、Please describe the process of the generation of a pseudogene we talked in this week class.

3. Genome Structure, Chromatin, and the Nucleosome - II

Assignment-week 3

1、Please describe the composition of a nucleosome.

2、Pleas describe the process of nucleosome assembly.

3、What are the function of N-terminal tail of core histones?

4、Please describe the experiment of digestion of nucleosomal DNA with micrococcal nuclease we talked in this week class.

4. Discussion

Assignment-week 4

1、Please describe the steps of experiment in the following paper. Dintzis H.M. Assembly of the peptide chains of hemoglobin. Proc Natl Acad Sci USA. 1961 Jan 16; 47:247-261.

5. The Structures of DNA and RNA

Assignment-week 5

1、See attachment.

2、What is base flipping? How do you understand it biological relevance?

3、You extracted plasmid A. You would like to know the approximate molecular mass of your plasmid by agarose gel electrophoresis. How would you do?

6. The Replication of DNA - I

Assignment-week 6

1、What do you know about the chemistry of DNA synthesis after this week study?

2、What are Okazaki Fragments?

3、What is the mechanism for the recognition of different dNTPs by DNA polymerases?

4、How do DNA polymerases distinguish between dNTPs and rNTPs?

7. The Replication of DNA - II

Assignment-week 7

1、How does primase activity influence the length of Okazaki Fragments?

2、Please describe the composition of telomerase.

3、Please explain the end replication process of linear chromosome by telomerase.

9. RNA Splicing and The Genetic Code

Assignment-week 9

1、What is RNA splicing?

2、What are the reasons for the splicing site recognition errors?

3、What are the three kinds of point mutations altering the genetic code?

4、What is suppressor gene?

8. Mechanisms of Transcription

Assignment-week 8

1、Please describe the events occurring in bacteria transcription elongation phase.

2、How does σ 70 factor mediate the binding of polymerase to the promoter?

3、What is the factor recognize the UP-element of bacterial promoter?

4、What are the elements of core promoter for RNA polymerase II?

10. Translation

Assignment-week 10

1、What is RBS?

2、What is Kozak sequence?

3、What is the second genetic code?

4、How does the SsrA RNA rescue ribosomes that translate broken mRNAs?

11. Transcriptional Regulation in Prokaryotes

Assignment-week 11

1、How does MerR function?

2、What is the mechanism to regulate the expression of heat shock proteins?

3、How does NtrC function?

12. Gene Regulation in Eukaryotes

Assignment-week 12

1、Please describe the differences in regulation between eukaryotes and prokaryotes.

2、How to identify the interaction between protein A and B using yeast two hybrid techonolgy?

3、Please explain what is epigenetic gene regulation with an example.

13. Final Exam

Final Exam

1、PART I: PAIR TWO ITEMS DIRECTEDLY RELATAED, MULTIPLE PAIRS MIGHT BE POSSIBLE. (Total 24 points, 3 points each) 1. A. A left handed-helix B. B form DNA C. Z form DNA D. A form DNA 2. A. Hyperchromicity B. Bases C. Ribose D. Phosphodierster bond E. Absorbance at a wavelength of about 260 nm 3. A. linker DNA B. H1 histone protein C. H3 histone protein D. H4 histone protein E. H2A histone protein F. H2B histone protein G. Histone N-Terminal tail 4. A. 30 nm fiber B. H1 histone protein C. H3 histone protein D. H4 histone protein E. H2A histone protein F. H2B histone protein G. Histone N-Terminal tail 5. A. driving force for DNA synthesis B. Hydrolysis of pyrophosphate (PPi) C. Primer:template junction D. Template ssDNA E. Primer 6. A. DNA polymerase enzymatic activity B. processive enzyme C. Exonuclease D. Primer E. template ssDNA 7. A. RNA Primer removal B. RNAse H C. DNA polymerase D. DNA ligase E. RNA polymerase 8. A. Protection of chromosome ends B. Telomere-binding proteins C. DNA T-loop at 3’ end D. Right handed double helix E. DNA polymerase

2、PART II: MULTIPLE / SINGLE CHOICE (Total 36 points, 4 points each) 1. The main difference between eukaryotic gene and prokaryotic gene is that _______. A. eukaryotic gene contains intron B. eukaryotic gene contains ORF C. eukaryotic gene contains promoter D. they use different codons 2. The function of enhancer is_______. A. enhance DNA replication B. enhance half life of a protein C. enhance gene transcription D. enhance the stability of a gene 3. Cognate tRNA is _______. A. the tRNAs recognize synonym mRNA codons B. many tRNAs recognize the same mRNA codons C. many tRNAs stand for the same amino acid D. many tRNAs recognized by the same aminoacyl-tRNA synthetase 4. Which of the following is not true about Group I intron splicing _______. A. a free G attacks 5’ splice site B. a branch point A attacks 5’splice site C. A 3’-OH group is resulted at the 5’ exon, which attacks the 5’ splice site D. Group I introns release a linear intron rather than a lariat 5. Which of the following is not true _______. A.Aminoacyl-tRNA formation is very accurate B.Ribosomes is able to discriminate between correctly or incorrectly charged tRNAs C.Ribosome recognize tRNAs but not amino acids D.The large and the small subunits undergone association and dissociation during each cycle of translation 6. Which of the following polymerase is responsible for transcription of 5S RNA? A. RNA polymerase I B. RNA polymerase II C. RNA polymerase III D. DNA polymerase 7. Which of the following factors/elements are responsible for translation initiation? A. Ribosome binding site (RBS) B. IF1 C. EF-G D. Initiator Trna E. RRF 8. Which of the following statements on genetic codon are NOT CORRECT? A. The codons are read in a 3’ to 5’ direction B. Codons are not overlapping and the message contains no gaps C. Message is translated in a fixed reading frame D. UAU is a stop codon E. The code is degenerate 9. Which of the following statements on tRNA are CORRECT? A. tRNA has a L-shaped tertiary structure B. The amino acids are attached to the CCA terminus of the acceptor stem by Aminoacyl tRNA synthetase C. One Aminoacyl tRNA synthetase charges all the tRNAs D. Aminoacyl tRNA synthetase charges tRNA and the large ribosome proofread the charged amino acids

3、PART III: MAJOR QUESTIONS (40 points) 1. What are the important molecular processes that required to converting the genetic information in a protein-coding gene (DNA) to a protein in eukaryotic cells? What are the cis-acting elements and trans-acting factors involved in each process?