分子生物学(福建农林大学) 中国大学mooc慕课答案2024版 m100720

作业第三单元 基因和染色体-2（基因概念的多样性） Chapter 2 Gene and Chromosome_ Homework

1、 请上传Chapter 2 Gene and Chromosome上直播课和慕课过程中所记的笔记（可以是提纲式或是思维导图，需要记录重点和难点，特别要记录下英文PPT中的专业单词，笔记请纸质记录，拍照后上传）    要求：1. 有章节题目；2. 要点大纲；3. 记录下重点难点；4. 可以用思维导图式；5. 记录下英文专业词汇；6. 不能出现个人信息。
评分规则:  100-99：有章节题目和要点大纲，逻辑清楚，内容完整详细，重点难点突出，有记下英文专业词汇，且书写工整；90-89： 有章节题目和要点大纲，逻辑清楚，内容完整，有重难点，但不突出，只有少数英文词汇；书写工整；80-79：有章节题目和要点大纲，逻辑清楚，但内容和重难点不够完整，没有英文词汇，书写不够工整；70-69：有章节题目，但是逻辑不清楚，但内容和重难点不够完整，没有英文词汇，书写不工整，版面很乱60：有交笔记，但是内容非常让人不满意。0：没有提交笔记

第三单元 基因和染色体-2（基因概念的多样性） Chapter 2 Gene and Chromome _ Test

1、 Watson & Crick won the noble prize in 1962 for their discoveries concerning:

A:the interaction between tumour viruses and the genetic material of the cell
B:the mobile genetic elements
C:the molecular structure of nucleic acids
D:the invention of the PCR method
答案: the molecular structure of nucleic acids

2、 Most of the stability of the double-stranded DNA structure is the result of

A: hydrogen bonding between purines.
B:the phosphodiester backbone.
C:the angle of the planes of the bases with respect to the helix axis.
D:the stacking interactions between base pair.
答案: the stacking interactions between base pair.

3、 It is easier to melt DNA richer in AT than GC because

A:it is more heat sensitive.
B:there is one less hydrogen bond in an AT base pair
C: the helix pitch is longer in AT rich regions.
D:All of the three statements.
答案: there is one less hydrogen bond in an AT base pair

4、 As B-DNA is gradually heated, the absorbance at 260 nm

A:increases.
B:decreases.
C:stays the same.
D: It is unpredictable.
答案: increases.

5、 What are the target and the probe of the Southern blotting？

A:DNA, DNA
B:RNA, RNA
C:Protein, antibody  
D: None of the above.
答案: DNA, DNA

6、 Supercoiling of pure circular DNA is a result of __. 

A:underwinding or overwinding of the helix
B:the long length of the strands
C:the lack of associated histones 
D:the activity of exonucleases
答案: underwinding or overwinding of the helix

7、 Which of the following is an example of highly-repetitive DNA?

A:Globin gene family 
B:Histone gene cluster
C:Minisatellite DNA
D:rDNA gene family
答案: Minisatellite DNA

8、 Histones are found in close association with DNA. Which of the following statements is incorrect?

A:A nucleosome core is composed of ~146 bp of DNA and a histone octamer.
B:Histone H1 binds to linker DNA.
C:There are only four types of histones.
D:Nucleosomes are evenly distribution within chromatin.
答案: There are only four types of histones.

9、 DNA wraps around an octamer of histones to form bead-like structures called __.

A:nucleoids
B:nucleosomes
C:nucleoli
D:chromatids
答案: nucleosomes

10、 What is the approximate diameter of a chromatin fiber?

A:3 nm 
B:30 nm
C:300 nm  
D:3 mm
答案: 30 nm

11、 What is the order of packaging of chromatin in eukaryotic cells from smallest to largest size?

A:double-helix → solenoid螺线管 → nucleosome → chromosome
B:double-helix → chromatin → solenoid → chromosome
C:single-stranded DNA → chromatin → histones → chromosome
D:double-helix → nucleosomes → solenoid → chromosome
答案: double-helix → nucleosomes → solenoid → chromosome

12、 How might mitochondrial DNA be distinguished from eukaryotic nuclear DNA?

A:Mitochondrial DNA is in the Z conformation, nuclear DNA is in the B conformation.
B:Mitochondrial DNA is methylated, nuclear DNA is not.
C:Nuclear DNA is linear, mitochondrial DNA are circular.
D:They cannot be distinguished and must be clearly separate during purification
答案: Nuclear DNA is linear, mitochondrial DNA are circular.

13、 Which of the following statements is not correct concerning to the prokaryotic genome and eukaryotic genome?

A:There are many non-coding DNAs in eukaryotic genome.
B:DNA are almost naked in prokaryotes.
C:There are many operons in eukaryotic genome.
D:Prokaryotic genome is a single circular DNA molecule.
答案: There are many operons in eukaryotic genome.

14、 Which does not apply to most bacterial DNA? 

A:Circular.  
B:Relaxed. 
C:Not packed into nucleosomes. 
D:Supercoiled. 
答案: Relaxed. 

15、 In a nucleic acid molecule, nucleotides are joined into a polymer by the __ phosphodiester bonds.

A:2′,3′  
B:2′,4′ 
C:3′, 4′ 
D:3′, 5′
答案: 3′, 5′

16、 All genomes are composed of DNA. 

A:正确
B:错误
答案: 错误

17、 The two strands of double-stranded DNA have the same content of each of the bases A, T, G and C.

A:正确
B:错误
答案: 错误

18、 The supercoiling of double-stranded circular DNA can be removed by cleaving a single phosphodiester bond on only one strand (nick). 

A:正确
B:错误
答案: 正确

19、 Prokaryotic DNA is organized into protein-DNA structures called nucleoids. 

A:正确
B:错误
答案: 正确

20、 Histone H1 is part of the histone octamer.

A:正确
B:错误
答案: 错误

21、 Heterochromatin make up most of the genome.

A:正确
B:错误
答案: 错误

22、 The maximum C-value is always greater than minimum C-value in an organism.

A:正确
B:错误
答案: 错误

作业第四单元 DNA的复制 Chapter 3 DNA replication-homework

1、 请上传Chapter 3 DNA replication上直播课和慕课过程中所记的笔记（可以是提纲式或是思维导图，需要记录重点和难点，特别要记录下英文PPT中的专业单词，笔记请纸质记录，拍照后上传）    要求：1. 有章节题目；2. 要点大纲；3. 记录下重点难点；4. 可以用思维导图式；5. 记录下英文专业词汇；6. 不能出现个人信息。
评分规则:  100-90：有章节题目和要点大纲，逻辑清楚，内容完整详细，重点难点突出，有记下英文专业词汇，且书写工整；89-80： 有章节题目和要点大纲，逻辑清楚，内容完整，有重难点，但不突出，只有少数英文词汇；书写工整；79-70：有章节题目和要点大纲，逻辑清楚，但内容和重难点不够完整，没有英文词汇，书写不够工整；69-61：有章节题目，但是逻辑不清楚，但内容和重难点不够完整，没有英文词汇，书写不工整，版面很乱60：有交笔记，但是内容非常让人不满意。0：没有提交笔记

第四单元 DNA的复制 Chapter 3 DNA replication -test

1、 All of the following statements about DNA replication in prokaryotes are true except:

A:DNA replication is conservative.
B:DNA synthesis occurs in the 5’ to 3’ direction.
C:Requires a 3’OH to initiate replication which is provided by an RNA primer.
D: DNA replication initiate from specific origin. 

答案: DNA replication is conservative.

2、 E. coli is grown on a medium containing 15N for a long time. Cells were then transferred to medium containing only normal 14N. DNA samples were obtained for analysis after three rounds of replication and centrifuged on a density gradient. How many bands can we see?

A:One with DNA containing both 15N and 14N.
B:Two, one with DNA containing only 15N and one with DNA containing only 14N.
C:Two, one with DNA containing both 15N and 14N and one with DNA containing only 14N.
D:Three, one with DNA containing only 15N, one with DNA containing both 15N and 14N and one with DNA containing only 14N.
答案: Two, one with DNA containing both 15N and 14N and one with DNA containing only 14N.

3、 Which DNA polymerase is most responsible for chain elongation in E. coli? 

A:DNA polymerase I.
B: DNA polymerase II. 
C:DNA polymerase III. 
D:DNA polymerase IV.
答案: DNA polymerase III. 

4、 The 3′ → 5′ exonuclease activity of E. coli DNA polymerase III accounts for the __ of polymerization. 

A:low error rate
B: high speed 
C:directionality
D:All of the above 
答案: low error rate

5、 The elongation of the lagging strand during DNA synthesis:

A:In the 3’ to 5’ direction
B:Produces Okazaki fragments 
C:Polymerizes in the direction of fork movement
D:Does not require a template strand
答案: Produces Okazaki fragments 

6、  In E.coli, the RNA primer at the beginning of each Okazaki fragment is removed by

A:DNA polymerase I.
B:DNA polymerase II.
C:DNA polymerase III.
D: DNA polymerase V.
答案: DNA polymerase I.

7、 Okazaki fragments are

A:the smallest subunits of DNA polymerase III
B:short stretches of DNA formed on the lagging strand 
C:short RNA primers needed for initiation of polymerization
D:fragments of DNA polymerase I that lack 5′ → 3′ exonuclease activity
答案: short stretches of DNA formed on the lagging strand 

8、 Fragments on the lagging strand are joined by the enzyme __.

A:DNA polymerase I
B:DNA synthase
C:DNA primosome
D:DNA ligase 
答案: DNA ligase 

9、 Which proteins are responsible for the unwinding of the double-stranded DNA during replication?

A:Ligases.
B:Helicases.
C:Topoisomerases.
D:Primases.
答案: Helicases.

10、  In E. coli, __ helps regulate the frequency of DNA replication.

A:DnaA
B:DnaB 
C:Tus
D:RecA
答案: DnaA

11、 What is the function of DNA topoisomerases?

A: Cleaving nucleotides from the ends of DNA. 
B:Adding or removing supercoils. 
C:Methylation of the nitrogenous bases. 
D:Methylation of the nitrogenous bases. 
答案: Adding or removing supercoils. 

12、 A major difference between prokaryotic and eukaryotic DNA replication mechanisms is

A:no Okazaki fragments are made in eukaryotes.
B:both leading and lagging strands are continuous in eukaryotes.
C:no primer synthesis is needed in eukaryotes.
D:the replication fork moves slower in eukaryotes.
答案: the replication fork moves slower in eukaryotes.

13、  Functions of DNA polymerases and accessory proteins in eukaryotic DNA replication include

A:PCNA protein, a sliding clamp unit for DNA.
B: DNA polymerase α, initiation the synthesis of new strands.
C:RPA protein, and equivalent of SSB proteins in bacteria.
D:All of the above. 
答案: All of the above. 

14、 DNA replication in eukaryotes:

A:usually starts at the same place every time
B:only involve 2 different DNA polymerases
C:is faster than in bacterial DNA replication
D:all of the above are false
答案: all of the above are false

15、 Which of the following are true statements regarding telomeres:

A:they consist of a short repeating sequence
B:they are primarily in eukaryotes
C:they are located at chromosome ends and stabilize linear chromosomes
D: all of the above
答案:  all of the above

16、 Telomerase is a kind of:

A:RNA polymerase
B:DNA polymerase
C: primase 
D:reverse transcriptase
答案: reverse transcriptase

17、 The methylation of GATC sequences in E. coli 

A:is performed by the dam methylase
B:is delayed for ~10 min after DNA synthesis
C: is related to the initiation of DNA replication.
D:all of the above
答案: all of the above

18、 In E. coli, replication begins at the origin of replication and proceeds in one direction until the entire circular DNA molecule has been copied.

A:正确
B:错误
答案: 错误

19、 DNA polymerase III is the largest DNA polymerase in E. coli.

A:正确
B:错误
答案: 正确

20、 The purpose of SSB is to prevent single-stranded DNA from folding back on itself to form double-helical regions. 

A:正确
B:错误
答案: 正确

21、  All DNA ligases use ATP as a cosubstrate.

A:正确
B:错误
答案: 错误

22、 Eukaryotic cells contain at least five DNA polymerases all of which are responsible for nuclear DNA replication.

A:正确
B:错误
答案: 错误

作业第五单元 基因突变与遗传重组 Chapter 4 Gene mutation and exchange-Homework

1、 请上传Chapter 4 Gene mutation and exchange 上直播课和慕课过程中所记的笔记（可以是提纲式或是思维导图，需要记录重点和难点，特别要记录下英文PPT中的专业单词，笔记请纸质记录，拍照后上传）   要求：1. 有章节题目；2. 要点大纲；3. 记录下重点难点；4. 可以用思维导图式；5. 记录下英文专业词汇；6. 不能出现个人信息。
评分规则:  100-90：有章节题目和要点大纲，逻辑清楚，内容完整详细，重点难点突出，有记下英文专业词汇，且书写工整；89-80： 有章节题目和要点大纲，逻辑清楚，内容完整，有重难点，但不突出，只有少数英文词汇；书写工整；79-70：有章节题目和要点大纲，逻辑清楚，但内容和重难点不够完整，没有英文词汇，书写不够工整；69-61：有章节题目，但是逻辑不清楚，但内容和重难点不够完整，没有英文词汇，书写不工整，版面很乱60：有交笔记，但是内容非常让人不满意。0：没有提交笔记

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