What Do You Know About Bacterial Conjugation? Trivia Facts Quiz

E. coli strains that are Hfr contain the F factor integrated in the bacterial chromosome. The F factor is a piece of DNA that can transfer genes between bacteria through a process called conjugation. When the F factor is integrated into the bacterial chromosome, it allows for the transfer of a larger portion of the chromosome during conjugation. This integration increases the frequency of recombination and gene transfer between bacteria. Therefore, E. coli strains that are Hfr have a high frequency of recombination, which is the opposite of what is stated in the answer choices.

Treating the cells chemically, exposing cells to a strong electric field, and making the cell membrane more permeable to DNA are all methods that can be used to create competent bacterial cells. These techniques help to increase the ability of the bacterial cells to take up and incorporate foreign DNA, such as plasmids, into their own genetic material. Treating the cells chemically can weaken the cell wall, making it easier for DNA to enter the cell. Exposing cells to a strong electric field, known as electroporation, creates temporary pores in the cell membrane, allowing DNA to pass through. Making the cell membrane more permeable to DNA can be achieved by using certain chemicals or by subjecting the cells to specific environmental conditions.

The viral chromosome of a bacteriophage can integrate into the host bacterium's chromosome. This process is known as lysogeny, where the viral DNA becomes a part of the bacterial DNA and is replicated along with it. This integration allows the viral DNA to be passed on to daughter cells during cell division. Therefore, the statement that the viral chromosome of a bacteriophage can never integrate into the host bacterium's chromosome is false.

Genetic exchange in bacteria by transduction does not require cell-to-cell contact. Transduction is a process where genetic material is transferred from one bacterium to another by a bacteriophage (a virus that infects bacteria). The bacteriophage acts as a carrier of the genetic material and transfers it between bacteria without direct contact between the cells. Therefore, the correct answer is False.

The correct answer is both plates. This is because the transformed cells now carry the wild-type (arg+) gene, which allows them to produce arginine. Therefore, they will be able to grow on both the plate supplemented with arginine and the plate lacking arginine. The presence of the plasmid carrying the wild-type gene ensures that the cells have the necessary genetic material to produce arginine, regardless of the availability of arginine in the medium.

In the case of genetic exchange in bacteria by transformation, there is no exchange of DNA back and forth between cells. Instead, a single strand of DNA is taken up by a recipient cell and incorporated into its own genome, resulting in a partially diploid cell. Therefore, the statement that a complete diploid cell is formed is incorrect.

Minimal media is a type of growth media that contains only the essential nutrients required for the growth of normal cells. It is designed to provide the minimal nutritional requirements for cell growth, without any unnecessary additives or supplements. This allows researchers to control and study specific cellular processes without interference from additional nutrients or contaminants. Minimal media is commonly used in laboratory settings to investigate the nutritional requirements of cells and to study their growth and metabolism under controlled conditions.

"Hot spots" in a gene refer to specific locations where mutations occur frequently. This means that these areas are more prone to genetic changes compared to other regions of the gene. Therefore, the statement that "hot spots" are locations in a gene where mutations are found at a relatively high frequency is true.

Bacterial transformation is a process where bacteria can take up foreign DNA from their environment. To enhance this process, bacterial cells can be induced to take up DNA by a strong electrical field, which is known as electroporation. This electrical field creates temporary pores in the bacterial cell membrane, allowing the DNA to enter the cell more efficiently. Therefore, the statement is true.

The statement is false because the genetic mapping experiments conducted by Seymour Benzer on rII mutants in the T4 phage showed that the gene is divisible by the process of mutation and recombination. This means that the gene can be broken down into smaller units and can be rearranged through mutation and recombination.

A temperate phage refers to a type of bacteriophage that has the ability to enter into a lysogenic or lytic cycle. In the lysogenic cycle, the phage integrates its genetic material into the host bacterium's genome and replicates along with it. This allows the phage to be passed on to future generations of bacterial cells without causing immediate cell death. On the other hand, in the lytic cycle, the phage immediately takes over the host bacterium's machinery to replicate and eventually causes cell lysis and death. Therefore, the statement that a temperate phage can be lytic or lysogenic is true.

In the lysogenic bacteriophage life cycle, the lambda chromosome inserts itself physically into the host cell's chromosome, allowing it to replicate and take over the bacterium. Additionally, the lambda chromosome expresses a repressor protein gene that inhibits the lytic pathway. Therefore, both statements B and C are correct.

The correct answer is circular. This is because the E. coli chromosome is a circular DNA molecule that is found in the cytoplasm of the bacteria. Unlike linear chromosomes found in eukaryotes, the circular chromosome of E. coli allows for efficient replication and gene expression. This circular structure also helps to prevent the loss of genetic material during cell division.

Auxotrophic bacterial strains require nutritional supplements to grow in a minimal medium. This means that these strains are unable to synthesize certain essential molecules or nutrients on their own and therefore rely on external sources for their growth. Autotrophic strains, on the other hand, are capable of synthesizing all necessary nutrients from inorganic sources. Prototrophic strains can synthesize all essential molecules and do not require any additional supplements. Phototrophic strains use light as an energy source for growth. Heterotrophic strains obtain energy from organic compounds.

In F+ × F- crosses, the F factor is transferred from the F+ bacterial chromosome to the F- bacterial chromosome. This means that the F- bacteria becomes F+ and gains the ability to transfer the F factor in future crosses. However, the rest of the bacterial chromosome is not transferred in this process. Therefore, the statement that none of the bacterial chromosome is transferred is true.

Co-transduction in bacteria can occur if two genes are closely linked enough so that they can be packaged into a phage head and injected into a cell by a single phage, or if two genes are introduced into the same bacterium by simultaneous infection with two different phages. In both cases, the genes are transferred together and can be co-transduced.

An Hfr cell has episomal DNA inserted in the cell's chromosome. Hfr stands for High frequency of recombination, which means that the F factor (a plasmid that allows for conjugation) has integrated into the bacterial chromosome. This integration allows for the transfer of both the F factor and some chromosomal DNA during conjugation. Therefore, an Hfr cell contains episomal DNA inserted in its chromosome. An F+ cell contains the F factor as a separate plasmid, an F' plasmid contains extra chromosomal DNA but not integrated into the chromosome, and an F- cell lacks the F factor altogether.

The transformation of most genes occurs at a frequency of one in every 1,000 cells. This means that out of every 1,000 cells, only one cell will undergo the transformation of the gene. The other 999 cells will not undergo this transformation.

In genetic exchange by conjugation, a single Hfr strain will not transfer the entire bacterial chromosome to the recipient. Instead, it transfers only a portion of the chromosome along with the F factor. This means that mapping the entire bacterial chromosome would not be possible in minutes from the first gene entering to the last one before the other half of the inserted F factor. Therefore, the statement is false.

An episome is a type of plasmid that is capable of integrating into the bacterial chromosome. It can exist as an independent extrachromosomal element or become integrated into the host chromosome. This ability allows the episome to be stably inherited during bacterial cell division. In contrast, a prophage is a bacteriophage that has integrated into the host genome, while auxisome, perisome, and elaiosome are not relevant to the integration of plasmids into the bacterial chromosome.

A merodiploid cell is a type of cell that contains two copies of one or a few specific genes, while having only one copy of all the other genes. This can occur due to a duplication event or the introduction of an extra copy of a gene. In this case, the statement is true because it accurately describes the characteristic of a merodiploid cell.

When an F- cell undergoes conjugation with an Hfr cell, the F- cell will remain F-. This is because an Hfr cell contains the F factor integrated into its chromosome, and during conjugation, the Hfr cell transfers a portion of its chromosome to the F- cell. However, the F factor itself is not transferred, so the F- cell does not become F+. Therefore, the correct answer is Hfr.

The statement is false because a complete bacterial medium contains not only the nutrients required for the growth of wild-type cells but also additional nutrients that may be required for the growth of mutant or genetically modified cells. These additional nutrients can support the growth of cells with specific nutritional requirements or genetic modifications that differ from the wild-type cells.

The reason that many plasmids used in laboratories for transformation experiments contain an ampicillin resistance gene (ampR) is to provide a selectable marker. This means that only the bacterial cells that have successfully taken up the plasmid and are able to produce the ampicillin resistance protein will survive and grow in the presence of ampicillin. This allows researchers to easily identify and select the transformed cells for further analysis.

Lederberg and Tatum's control in their experiments on gene transfer in bacteria was to plate strain A and strain B separately onto minimal media plates. This control allowed them to screen for spontaneous prototrophs, which are bacteria that can grow on minimal media without any additional nutrients. By plating the strains separately, they could determine if any prototrophs that grew were the result of gene transfer between the two strains or if they were simply spontaneous mutations. This control helped them to establish a baseline for comparison and to identify the specific effects of gene transfer through conjugation.

The interrupted mating experiment shows that xyl exconjugants appeared at 7 minutes and reached maximum level by 30 minutes. This indicates that xyl is the closest gene to the insertion site. The mtl gene function exconjugants appeared at 11 minutes and leveled off at 80% maximum by about 33 minutes, suggesting that mtl is the second closest gene to the insertion site. polA did not appear until 24 minutes into the experiment and slowly rose to about 30%, indicating that it is the farthest gene from the insertion site. Therefore, the correct gene order with the insertion site correctly is polA mtl xyl.

The production of r+ recombinants in a genetic cross between two bacteriophage T4 rII mutants suggests that the genetic changes in these mutants must be heteroallelic. Heteroallelic means that the two mutants have different alleles at the same locus, which allows for recombination to occur. This recombination can result in the production of recombinant offspring with a combination of traits from both parental mutants.

In E. coli, λ DNA integrates into the att site on the bacterial chromosome. The att site is a specific region where the λ DNA is inserted and integrated into the host genome. This integration allows the λ DNA to become a part of the bacterial chromosome and replicate along with it. The att site is essential for the lysogenic cycle of the λ phage, where it remains dormant in the host genome until conditions are favorable for the phage to enter the lytic cycle and produce new phage particles.

Prototrophic bacteria are able to synthesize all the necessary nutrients they need for growth on their own, including amino acids and vitamins. Therefore, they do not require amino acid or vitamin supplements to grow on an artificial medium. Additionally, sunlight is not a requirement for the growth of bacteria. Hence, the correct answer is "None of these."

Cotransduction can be detected when the transduced genes are closely linked on the same chromosome. This means that the genes are located close to each other on the same chromosome and are likely to be transduced together during the process of transduction.