Question 1

A 16 kb linear DNA is cut with EcoRI and BamHI.The EcoRI digest yields fragments of 2,6,and 8 kb.The BamHI digest yields fragments of 5 and 11 kb.An EcoRI-BamHI double digest yields 2,3,5,and 6 kb fragments.If the 3 kb fragment from the double digest is used as the probe in a Southern blot of the EcoRI digest,to which fragment(s)will it hybridize?

Accepted Answer

The answer of A 16 kb linear DNA is cut...

Question 2

A 6-base cutting enzyme should cut every 4 kb,on average.Approximately how many sites are in the human genome (for simplicity,use 4 million kb as the size of the human genome)?

Accepted Answer

The answer of A 6-base cutting enzyme should cut every...

Question 3

Ifa single DNA molecule is amplified by PCR,how many DNA molecules will there be after six cycles?

Accepted Answer

Each cycle of PCR doubles the number of DNA molecules, so after 6 cycles, the number of DNA molecules will be 2^6 = 64. Therefore, the correct answer is D) 64.

Question 4

If the restriction enyzme EcoRI cuts a linear 19 kb piece of DNA into fragments of 1,3,6,and 9 kb,what size fragment (in kb)would not be possible from a partial digest?

Accepted Answer

The answer of If the restriction enyzme EcoRI cuts a...

Question 5

Which mutation in the β-globin gene could,in theory,be detected with a genomic clone but not with a cDNA clone?

Accepted Answer

A promoter mutation that prevents transcription would not be present in cDNA, as cDNA is synthesized from mRNA, which would not be produced if transcription is prevented.

Question 6

Which statements are true?
i.In thalassemia,globin proteins are produced,but contain a point mutation.
ii.In sickle-cell anaemia,globin proteins are produced,but contain a point mutation.
iii.Sickle-cell anaemia is caused by a mutation in the β-globin gene.
iv.Sickle cell anaemia is caused by a mutation in the α-globin gene.

Accepted Answer

Both statements ii and iii are true. In sickle-cell anaemia, the β-globin gene is mutated, leading to the production of abnormal haemoglobin proteins, which cause red blood cells to take on a sickle shape. Thalassemia, on the other hand, is caused by mutations in the α- or β-globin genes, resulting in a decreased production of normal haemoglobin proteins. Therefore, statement iv is false.

Question 7

Pseudogenes are evidence for

Accepted Answer

Pseudogenes are non-functional copies of genes that have arisen from gene duplications. Therefore, their existence is evidence for gene duplications.

Question 8

A restriction enzyme with a recognition site of 10 bp cuts an average of every

Accepted Answer

A restriction enzyme with a recognition site of 10 base pairs will cut on average every 4^10 base pairs, because each position in the recognition site can be one of 4 nucleotides (A, T, C, or G).

Question 9

Where do restriction enzymes come from,and what is their normal physiological function?

Accepted Answer

Restriction enzymes are produced by bacteria as a defense mechanism against invading viruses (phages). They cleave the viral DNA, preventing replication and thus protecting the bacterial host.

Question 10

How do bacteria protect their own DNA from the restriction enzymes they produce?

Accepted Answer

Bacteria add methyl groups to their DNA at recognition sequences to protect it from their own restriction enzymes. The enzymes cannot cleave the methylated DNA, allowing the bacteria to maintain intact genomes.

Question 11

How are the genes in the beta-globin locus different from each other?

Accepted Answer

The genes in the beta-globin locus are expressed at different times in development, allowing for the production of different forms of hemoglobin at various stages of human growth, from embryonic development through adulthood.

Question 12

Which choice is not a characteristic of a plasmid used as a cloning vector?

Accepted Answer

Plasmids used as cloning vectors are typically engineered to avoid methylation, as methylation can interfere with the cloning process by making the DNA susceptible to digestion by the host cell's restriction enzymes. The other options (A, B, C, D) are characteristics of plasmids used in cloning.

Question 13

The genetically determined molecular composition of haemoglobin changes several times during development including changing from embryonic,to fetal,to adult hemoglobin.

Accepted Answer

The genetically determined molecular composition of hemoglobin does change several times during development, notably from embryonic to fetal to adult hemoglobin.

Question 14

A circular DNA of 1 kb length is cut with a restriction enzyme whose precise recognition sequence is not known.The digest yields four fragments of approximately equal size.What is the most likely conclusion from these data?

Accepted Answer

Given that the DNA is cut into four fragments of approximately equal size, it suggests that the enzyme cuts the DNA at regular intervals. A 4-base cutter would recognize more frequent sites in a given length of DNA compared to 6-base or 8-base cutters, leading to a higher number of cuts over the same length, which aligns with the observation of four fragments from a 1 kb circular DNA.

Question 15

When bacterial transformants containing a library are transferred to nitrocellulose filters and screened,one of the steps is treatment with an alkaline solution.What does this do?

Accepted Answer

Treatment with an alkaline solution lyses the cells and denatures the released DNA, allowing it to bind to the nitrocellulose filter. This step is known as Southern blotting and is used to transfer DNA from a gel onto a membrane for probing.

Question 16

A 16 kb linear DNA is cut with EcoRI and BamHI.The EcoRI digest yields fragments of 2,6,and 8 kb.The BamHI digest yields fragments of 5 and 11 kb.An EcoRI-BamHI double digest yields 2,3,5,and 6 kb fragments.The map of this DNA has

Accepted Answer

The answer of A 16 kb linear DNA is cut...

Question 17

Which technique is required to generate a restriction map?

Accepted Answer

The answer of Which technique is required to generate a...

Question 18

A 10 kb linear DNA is cut with EcoRI and HindIII.The EcoRI digest yields fragments of 2 and 8 kb.The HindIII digest yields fragments of 3 and 7 kb.What are the possible fragments (in kb)from an EcoRI-HindIII double digest?

Accepted Answer

The EcoRI digest produces fragments of 2 and 8 kb, which means that the recognition site of EcoRI is located in the middle of the original 10 kb DNA. Therefore, the EcoRI digest splits the original DNA into two fragments of equal size.
The HindIII digest produces fragments of 3 and 7 kb, which means that the recognition site of HindIII is not located in the middle of the original 10 kb DNA.
When combining the digestions, the fragments generated will have one end that is from the EcoRI digestion and another end from the HindIII digestion. The 2 kb EcoRI fragment will pair with the 7 kb HindIII fragment to generate a fragment of size 9 kb. The 8 kb EcoRI fragment will pair with the 3 kb HindIII fragment to generate a fragment of size 11 kb. The only possible remaining fragment is 1 kb, which is generated by one of the cleavages from the HindIII digestion that does not combine with any of the EcoRI fragments. Therefore, the possible fragments from the EcoRI-HindIII double digest are 1,2,7 or 2,3,5. The correct answer is E.

Question 19

What is the function of the amp^r gene in a vector?

Accepted Answer

The amp^r gene typically refers to an ampicillin resistance gene, which serves as a selectable marker in a vector. This allows for the selection of cells that have been successfully transformed with the vector by their ability to grow in the presence of ampicillin.

Question 20

In references to the "alpha-globin locus" or "beta-globin locus",the term "locus" means

Accepted Answer

In genetics, a locus refers to a specific location on a chromosome. The alpha-globin locus and beta-globin locus are specific chromosome regions where the respective clusters of genes encoding alpha-globin and beta-globin proteins are located. Therefore, answer B is the best choice as it accurately describes the meaning of "locus" in this context. Answers A, C, D, and E are not accurate descriptions of the term "locus" in this context.

Quiz 13: Bacterial Genetics

A 6-base cutting enzyme should cut every 4 kb,on average.Approximately how many sites are in the human genome (for simplicity,use 4 million kb as the size of the human genome) ?

Ifa single DNA molecule is amplified by PCR,how many DNA molecules will there be after six cycles?

If the restriction enyzme EcoRI cuts a linear 19 kb piece of DNA into fragments of 1,3,6,and 9 kb,what size fragment (in kb) would not be possible from a partial digest?

Which mutation in the β-globin gene could,in theory,be detected with a genomic clone but not with a cDNA clone?

Pseudogenes are evidence for

A restriction enzyme with a recognition site of 10 bp cuts an average of every

Where do restriction enzymes come from,and what is their normal physiological function?

How do bacteria protect their own DNA from the restriction enzymes they produce?

How are the genes in the beta-globin locus different from each other?

Which choice is not a characteristic of a plasmid used as a cloning vector?

The genetically determined molecular composition of haemoglobin changes several times during development including changing from embryonic,to fetal,to adult hemoglobin.

A circular DNA of 1 kb length is cut with a restriction enzyme whose precise recognition sequence is not known.The digest yields four fragments of approximately equal size.What is the most likely conclusion from these data?

When bacterial transformants containing a library are transferred to nitrocellulose filters and screened,one of the steps is treatment with an alkaline solution.What does this do?

A 16 kb linear DNA is cut with EcoRI and BamHI.The EcoRI digest yields fragments of 2,6,and 8 kb.The BamHI digest yields fragments of 5 and 11 kb.An EcoRI-BamHI double digest yields 2,3,5,and 6 kb fragments.The map of this DNA has

Which technique is required to generate a restriction map?

A 10 kb linear DNA is cut with EcoRI and HindIII.The EcoRI digest yields fragments of 2 and 8 kb.The HindIII digest yields fragments of 3 and 7 kb.What are the possible fragments (in kb) from an EcoRI-HindIII double digest?

What is the function of the amp^r gene in a vector?

In references to the "alpha-globin locus" or "beta-globin locus",the term "locus" means

Quiz 13: Bacterial Genetics

A 6-base cutting enzyme should cut every 4 kb,on average.Approximately how many sites are in the human genome (for simplicity,use 4 million kb as the size of the human genome) ?

Ifa single DNA molecule is amplified by PCR,how many DNA molecules will there be after six cycles?

If the restriction enyzme EcoRI cuts a linear 19 kb piece of DNA into fragments of 1,3,6,and 9 kb,what size fragment (in kb) would not be possible from a partial digest?

Which mutation in the β-globin gene could,in theory,be detected with a genomic clone but not with a cDNA clone?

Pseudogenes are evidence for

A restriction enzyme with a recognition site of 10 bp cuts an average of every

Where do restriction enzymes come from,and what is their normal physiological function?

How do bacteria protect their own DNA from the restriction enzymes they produce?

How are the genes in the beta-globin locus different from each other?

Which choice is not a characteristic of a plasmid used as a cloning vector?

The genetically determined molecular composition of haemoglobin changes several times during development including changing from embryonic,to fetal,to adult hemoglobin.

A circular DNA of 1 kb length is cut with a restriction enzyme whose precise recognition sequence is not known.The digest yields four fragments of approximately equal size.What is the most likely conclusion from these data?

When bacterial transformants containing a library are transferred to nitrocellulose filters and screened,one of the steps is treatment with an alkaline solution.What does this do?

A 16 kb linear DNA is cut with EcoRI and BamHI.The EcoRI digest yields fragments of 2,6,and 8 kb.The BamHI digest yields fragments of 5 and 11 kb.An EcoRI-BamHI double digest yields 2,3,5,and 6 kb fragments.The map of this DNA has

Which technique is required to generate a restriction map?

A 10 kb linear DNA is cut with EcoRI and HindIII.The EcoRI digest yields fragments of 2 and 8 kb.The HindIII digest yields fragments of 3 and 7 kb.What are the possible fragments (in kb) from an EcoRI-HindIII double digest?

What is the function of the ampr gene in a vector?

In references to the "alpha-globin locus" or "beta-globin locus",the term "locus" means

What is the function of the amp^r gene in a vector?