Question 1

A transgenic mouse is different from a knockout mouse in that:

Accepted Answer

The answer of A transgenic mouse is different from a...

Question 2

Embryonic stem (ES)cells have the unique ability to:

Accepted Answer

Embryonic stem cells have the ability to combine with other stem cells to generate a chimeric mouse pup. Chimeric mice have cells derived from multiple sources, including the ES cells, and can be used to study gene function and tissue development. ES cells cannot form a mouse pup without additional cells from a developing embryo. They also do not necessarily grow in the presence of gancyclovir or eliminate specific genes in response to chemical cues, although genetic engineering techniques can be used to modify their gene expression. While ES cells do have a high proliferation rate, this is not their unique ability.

Question 3

Thymidine kinase is valuable in the targeting of mouse genes because:

Accepted Answer

Thymidine kinase allows researchers to enrich cells that have undergone homologous recombination by selecting for cells that are resistant to the drug gancyclovir. Gancyclovir is toxic to cells that express thymidine kinase, which is often used as a selectable marker in gene targeting experiments. Thus, cells that have undergone homologous recombination and contain the thymidine kinase gene will be resistant to gancyclovir, allowing them to be selected and enriched in cell culture.

Question 4

In the study of genetics,a "library" denotes:

Accepted Answer

In genetics, a "library" refers to a collection of DNA fragments isolated from a particular group of cells or tissue, representing the genetic content of those cells. These libraries can be used for various genetic analyses, such as sequencing or constructing genetic maps.

Question 5

What type of library would be most valuable in the isolation of promoter sequences found in front of a gene's transcriptional start site?

Accepted Answer

A genomic DNA library is the best choice for isolating promoter sequences found in front of a gene's transcriptional start site as it contains the complete set of DNA sequences from an organism, including promoter regions. Promoter sequences are located upstream of the transcriptional start site and can vary in length, making isolation from a cDNA library difficult. A mutant genomic DNA library would not be useful in this case as it would contain mutations in the DNA sequence, potentially affecting the promoter region. miRNA and repetitive DNA libraries are unrelated to the isolation of promoter sequences.

Question 6

Which of the following organisms can be made transgenic by injection of DNA into the gonad,generating extrachromosomal arrays of the transgene in some egg cells?

Accepted Answer

Caenorhabditis elegans can be made transgenic by injection of DNA into the gonad, generating extrachromosomal arrays of the transgene in some egg cells. This is a commonly used method in C. elegans research. The other organisms listed have different methods for generating transgenic individuals.

Question 7

Suppose you cut two different DNAs,

$$\begin{array} { l l } 
\text { one wih BamH1: } & \text { 5'-GGATCC-3' } \
& \text { 3'-CCTAGG-5' } \\
\text { and one with BglII: } & \text { 5'-A GATCT-3' } \
& \text { 3'-TCTAG A-5' }
\end{array}$$

then ligate them together through their compatible sticky ends.Once joined,could you separate these two DNAs again with either restriction enzyme? Why or why not? (Each of these enzymes is cut between the first two nucleotides,at the 5? end of each strand of the palindrome.)

Accepted Answer

The answer of Suppose you cut two different DNAs,

\[\begin{array} {...

Question 8

Restriction endonucleases BamH1,NheI,XbaI,and EcoRI make sequence-specific cuts in DNA at the following sequences:
BamHI: $\quad $ 5'-GGATCC-3'
NheI:  $\quad $ $\quad $5'-GCTAGC-3'
XbaI:  $\quad $ $\quad $5'-TCTAGA-3'
EcoRI:  $\quad $ $\quad $5'-GAATTC-3'
All these enzymes break a phosphodiester bond between the first and second nucleotide (counting from the 5' end),leaving a 5' P and a 3' OH.
Could ligase covalently join two ends produced by the following enzymes? If so,would ligation regenerate one of the above restriction sites?
(1)two BamH1 ends?
(2)two XbaI ends?
(3)a BamH1 and an EcoRI end?
(4)an XbaI and an NheI end?
(5)a BamH1 and an NheI end?

Accepted Answer

The answer of Restriction endonucleases BamH1,NheI,XbaI,and EcoRI make sequence-specific cuts...

Question 9

Foreign DNA can be introduced into a cell using which of the following method/s?

Accepted Answer

All of the answer options are correct. Transformation involves using bacterial cells and can be done by electroporation or heat shock. The projectile gun method or biolistics can be used on plant cells. Injection can be done on animal cells. Virus infection can be used as a natural means to introduce foreign DNA into cells.

Question 10

Transgenic plants can be generated using T-DNA plasmid carrying a gene of interest.To get the DNA into the plant cells,the researchers:

Accepted Answer

The most common method for introducing T-DNA into plant cells involves co-cultivation with a strain of Agrobacterium tumefaciens that carries the T-DNA plasmid. The T-DNA is then transferred into the plant cell, resulting in the integration of the gene of interest into the plant genome. This method is widely used because it is relatively simple, efficient, and does not require complex equipment or specialized skills.

Question 11

Bacterial cells have a variety of restriction enzymes that can degrade the DNA of an attacking virus.How do these bacterial cells protect their own DNA from being degraded by the very restriction enzymes that are meant to help them?

Accepted Answer

The answer of Bacterial cells have a variety of restriction...

Question 12

A 3-kb supercoiled circular plasmid contains the restriction sites shown below.N and X represent NheI and XbaI sites,respectively;A through F mark six points on the plasmid.A preparation of plasmid DNA was separately digested to completion with XbaI alone,NheI alone,and a mixture of the two enzymes.The products were separated by agarose gel electrophoresis.Draw the predicted appearance of the gel,assuming that you ran the following in the various lanes.  
Lane M (size markers)-a mixture of known markers increasing in size from 1 kb to 6 kb,in steps of 1 kb
Lane 1-sample from the original plasmid DNA preparation
Lane 2-products of complete digestion with XbaI alone
Lane 3-products of complete digestion with NheI alone
Lane 4-products of complete digestion with XbaI plus NheI

Accepted Answer

The answer of A 3-kb supercoiled circular plasmid contains the...

Question 13

Homologous recombination in yeast facilitates the:

Accepted Answer

Homologous recombination in yeast can be used for targeted replacement of a gene in a living yeast cell, also known as gene editing or genetic engineering. This technique can be used to knock out or replace specific genes, which has important applications in scientific research and biotechnology.

Question 14

This linear vector is comprised of bacteriophage genome components and can carry cloned DNA up to 15 kb in size.

Accepted Answer

Lambda vectors are derived from the lambda bacteriophage and are designed to carry DNA inserts of up to about 15 kb, making them suitable for cloning moderately large DNA fragments.

Question 15

Bacterial artificial chromosomes are comprised of:

Accepted Answer

Bacterial artificial chromosomes are modified plasmids from bacteria that can carry large fragments of foreign DNA. They were first created using components of the bacterial F plasmid, allowing them to carry up to 200,000 base pairs of DNA.

Question 16

Detection of a transgenic plant can be accomplished in a number of different ways,but often the initially transformed cells (in tissue culture)are enriched for the presence of a transgene by:

Accepted Answer

By placing the potentially transformed cells in the presence of a drug that inhibits the division of non-transgenic cells, only the transformed cells would survive and divide, thereby enriching for the presence of the transgene. This method is often used in the selection of transformed plant cells in tissue culture. Option A is also possible, but it involves screening groups of cells using the polymerase chain reaction, which can be time-consuming and expensive. Option B is not reliable as not all transgenic plants display a visible phenotype. Option D is not practical as it is difficult to isolate cells with "extra" DNA in a mixture of many cells in tissue culture. Option E is not accurate as transgenesis can be selected for in tissue culture.

Question 17

The value of the beta-galactosidase gene in cloning could best be described as the gene:

Accepted Answer

The beta-galactosidase gene is commonly used as a reporter gene in cloning to indicate whether a recombinant product has formed. This is often achieved by inserting the gene into a plasmid alongside the gene of interest, and then screening for the production of active beta-galactosidase enzyme in transformed cells. The presence of the recombinant product will disrupt the expression of the beta-galactosidase gene, resulting in a measurable decrease in enzyme activity.

Question 18

A cDNA library is produced from ______________ and is valued in the analysis of __________________.

Accepted Answer

A cDNA library is produced from a DNA copy of mRNA isolated from a group of cells. This library represents the protein-encoding open reading frame of a gene without introns, which makes it valuable for analyzing gene expression and identifying gene sequences.

Question 19

In Southern and Northern blotting,the probe being used to analyze DNA or RNA identifies the target sequence via:

Accepted Answer

In Southern and Northern blotting, the probe is a single-stranded nucleic acid molecule labeled with a radioactive or fluorescent tag. The probe is designed to be complementary to the target DNA or RNA sequence of interest. This complementary annealing between the probe and the gene target allows for the identification and detection of the target sequence. The other answer choices are not accurate descriptions of the probe-target interaction in Southern or Northern blotting.

Question 20

When seeking to identify the gene that is responsible for a particular cellular characteristic,scientists will generate cells carrying a recessive mutation that perturbs the characteristic of interest and then try to identify or "clone" the wild-type copy of that gene through functional complementation.This type of complementation could be described as:

Accepted Answer

Functional complementation involves the introduction of a wild-type copy of a gene, typically via a plasmid, to rescue the phenotype caused by a recessive mutant allele. This process results in the reversal or rescue of the recessive mutant trait.

Quiz 10: Gene Isolation and Manipulation