Prokaryotic Genetics - MCAT Biological and Biochemical Foundations of Living Systems
Card 1 of 136
What is the structure in prokaryotic cells that often holds antibiotic resistance genes?
What is the structure in prokaryotic cells that often holds antibiotic resistance genes?
Tap to reveal answer
Antibiotic resistance genes are often found on plasmids, which are small DNA molecules which are easily transfered to other prokaryotic cells.
Antibiotic resistance genes are often found on plasmids, which are small DNA molecules which are easily transfered to other prokaryotic cells.
← Didn't Know|Knew It →
In a small village, a doctor over-prescribed Ciprofloxin (an antiobiotic) to his patients. The result was that the majority of his patients had developed a new strain of bacteria that had become resistant to Ciprofloxin.
What is a possible route that may have caused these bacteria to become antibiotic resistant?
In a small village, a doctor over-prescribed Ciprofloxin (an antiobiotic) to his patients. The result was that the majority of his patients had developed a new strain of bacteria that had become resistant to Ciprofloxin.
What is a possible route that may have caused these bacteria to become antibiotic resistant?
Tap to reveal answer
Antibiotic resistant genes are commonly transferred through plasmids. Plasmids are small, circular, extra-chromosomal pieces of DNA that contain supplemental genes, which can be passed from bacteria to bacteria.
Antibiotic resistant genes are commonly transferred through plasmids. Plasmids are small, circular, extra-chromosomal pieces of DNA that contain supplemental genes, which can be passed from bacteria to bacteria.
← Didn't Know|Knew It →
Which of these processes is the means by which a bacterium can directly uptake and incorporate foreign DNA from the environment into its genome?
Which of these processes is the means by which a bacterium can directly uptake and incorporate foreign DNA from the environment into its genome?
Tap to reveal answer
Transformation is defined as the process by which bacteria can incorporate exogenous DNA from the environment into their genome via direct uptake. Transduction and conjugation are also processes by which exogenous DNA is incorporated, but involve other methods.
Transformation is defined as the process by which bacteria can incorporate exogenous DNA from the environment into their genome via direct uptake. Transduction and conjugation are also processes by which exogenous DNA is incorporated, but involve other methods.
← Didn't Know|Knew It →
Frederick Griffith's experiments showed that formerly harmless IIR bacteria had become deadly in mice. This change took place when the harmless IIR bacteria were exposed to the remains of heat killed IIIS bacteria. Based on this experiment, what was the process that converted the harmless bacteria to a deadly strain?
Frederick Griffith's experiments showed that formerly harmless IIR bacteria had become deadly in mice. This change took place when the harmless IIR bacteria were exposed to the remains of heat killed IIIS bacteria. Based on this experiment, what was the process that converted the harmless bacteria to a deadly strain?
Tap to reveal answer
The IIR bacteria became deadly when exposed to the remains of the IIIS bacteria. This means that the IIR bacteria managed to receive genetic material from the environment and incorporate it into their genome. This is an example of transformation, a process that results in genetic recombination. In this case, the recombination made the formerly harmless bacteria deadly in mice.
Transduction is the process by which new genetic information is introduced to a bacterium via a vector, such as a bacteriophage. Conjugation is the transfer of genetic material between bacteria via a sex pilus. Binary fission is not a means of recombination; rather, the parent cell divides to produce two identical copies of itself.
The IIR bacteria became deadly when exposed to the remains of the IIIS bacteria. This means that the IIR bacteria managed to receive genetic material from the environment and incorporate it into their genome. This is an example of transformation, a process that results in genetic recombination. In this case, the recombination made the formerly harmless bacteria deadly in mice.
Transduction is the process by which new genetic information is introduced to a bacterium via a vector, such as a bacteriophage. Conjugation is the transfer of genetic material between bacteria via a sex pilus. Binary fission is not a means of recombination; rather, the parent cell divides to produce two identical copies of itself.
← Didn't Know|Knew It →
Sexually transmitted diseases are a common problem among young people in the United States. One of the more common diseases is caused by the bacterium Neisseria gonorrhoeae, which leads to inflammation and purulent discharge in the male and female reproductive tracts.
The bacterium has a number of systems to evade host defenses. Upon infection, it uses pili to adhere to host epithelium. The bacterium also uses an enzyme, gonococcal sialyltransferase, to transfer a sialyic acid residue to a gonococcal surface lipooligosaccharide (LOS). A depiction of this can be seen in Figure 1. The sialyic acid residue mimics the protective capsule found on other bacterial species.
Once infection is established, Neisseria preferentially infects columnar epithelial cells in the female reproductive tract, and leads to a loss of cilia on these cells. Damage to the reproductive tract can result in pelvic inflammatory disease, which can complicate pregnancies later in the life of the woman.
A doctor uses a new antibiotic to fight off Neisseria infection. Shortly thereafter, resistance develops and the doctor finds that inoculating wild type bacteria with the pure DNA of resistant Neisseria organisms produces resistant colonies. Which of the following is the method of modification that the doctor is using?
Sexually transmitted diseases are a common problem among young people in the United States. One of the more common diseases is caused by the bacterium Neisseria gonorrhoeae, which leads to inflammation and purulent discharge in the male and female reproductive tracts.
The bacterium has a number of systems to evade host defenses. Upon infection, it uses pili to adhere to host epithelium. The bacterium also uses an enzyme, gonococcal sialyltransferase, to transfer a sialyic acid residue to a gonococcal surface lipooligosaccharide (LOS). A depiction of this can be seen in Figure 1. The sialyic acid residue mimics the protective capsule found on other bacterial species.
Once infection is established, Neisseria preferentially infects columnar epithelial cells in the female reproductive tract, and leads to a loss of cilia on these cells. Damage to the reproductive tract can result in pelvic inflammatory disease, which can complicate pregnancies later in the life of the woman.
A doctor uses a new antibiotic to fight off Neisseria infection. Shortly thereafter, resistance develops and the doctor finds that inoculating wild type bacteria with the pure DNA of resistant Neisseria organisms produces resistant colonies. Which of the following is the method of modification that the doctor is using?
Tap to reveal answer
Transformation is the uptake of nucleic acid by competent cells, as was described in this question. Conjugation invovles cell-to-cell DNA transfer and transduction involves the use of a viral vector.
Transformation is the uptake of nucleic acid by competent cells, as was described in this question. Conjugation invovles cell-to-cell DNA transfer and transduction involves the use of a viral vector.
← Didn't Know|Knew It →
What type of prokaryotic genetic recombination requires the presence of plasmids?
What type of prokaryotic genetic recombination requires the presence of plasmids?
Tap to reveal answer
Conjugation is a type of genetic recombination that requires one bacterium to have the F-plasmid in order to create a sex pilus. This sex pilus will connect with another bacterium and allow DNA to pass between the bacteria.
Transduction is the transfer of genetic information to a bacterium via a vector, such as a bacteriophage. Transformation occurs when a bacterial cell receives genetic material from its surrounding environment. Binary fission does not involve recombination, and is the term for bacterial cell division that results in two identical offspring from a single parental cell.
Conjugation is a type of genetic recombination that requires one bacterium to have the F-plasmid in order to create a sex pilus. This sex pilus will connect with another bacterium and allow DNA to pass between the bacteria.
Transduction is the transfer of genetic information to a bacterium via a vector, such as a bacteriophage. Transformation occurs when a bacterial cell receives genetic material from its surrounding environment. Binary fission does not involve recombination, and is the term for bacterial cell division that results in two identical offspring from a single parental cell.
← Didn't Know|Knew It →
Sexually transmitted diseases are a common problem among young people in the United States. One of the more common diseases is caused by the bacterium Neisseria gonorrhoeae, which leads to inflammation and purulent discharge in the male and female reproductive tracts.
The bacterium has a number of systems to evade host defenses. Upon infection, it uses pili to adhere to host epithelium. The bacterium also uses an enzyme, gonococcal sialyltransferase, to transfer a sialyic acid residue to a gonococcal surface lipooligosaccharide (LOS). A depiction of this can be seen in Figure 1. The sialyic acid residue mimics the protective capsule found on other bacterial species.
Once infection is established, Neisseria preferentially infects columnar epithelial cells in the female reproductive tract, and leads to a loss of cilia on these cells. Damage to the reproductive tract can result in pelvic inflammatory disease, which can complicate pregnancies later in the life of the woman.
The doctor wants to study the resistance further, so he creates a bacteriophage that transmits the plasmid to other bacterial cells to produce new resistant colonies. Which of the following is the method that the doctor is now using?
Sexually transmitted diseases are a common problem among young people in the United States. One of the more common diseases is caused by the bacterium Neisseria gonorrhoeae, which leads to inflammation and purulent discharge in the male and female reproductive tracts.
The bacterium has a number of systems to evade host defenses. Upon infection, it uses pili to adhere to host epithelium. The bacterium also uses an enzyme, gonococcal sialyltransferase, to transfer a sialyic acid residue to a gonococcal surface lipooligosaccharide (LOS). A depiction of this can be seen in Figure 1. The sialyic acid residue mimics the protective capsule found on other bacterial species.
Once infection is established, Neisseria preferentially infects columnar epithelial cells in the female reproductive tract, and leads to a loss of cilia on these cells. Damage to the reproductive tract can result in pelvic inflammatory disease, which can complicate pregnancies later in the life of the woman.
The doctor wants to study the resistance further, so he creates a bacteriophage that transmits the plasmid to other bacterial cells to produce new resistant colonies. Which of the following is the method that the doctor is now using?
Tap to reveal answer
The use of bacteriophage viral vectors to transmit genetic information is transduction, an alternative form of genetic modification to transformation or conjugation. Transformation involves direct uptake of genetic material. Conjugation involves cell-to-cell transfer of DNA.
The use of bacteriophage viral vectors to transmit genetic information is transduction, an alternative form of genetic modification to transformation or conjugation. Transformation involves direct uptake of genetic material. Conjugation involves cell-to-cell transfer of DNA.
← Didn't Know|Knew It →
Which answer choice correctly pairs the mode of bacterial genetic transfer with its definition?
Which answer choice correctly pairs the mode of bacterial genetic transfer with its definition?
Tap to reveal answer
The three main modes of genetic transfer for prokaryotes are transformation, transduction, and conjugation. Transformation occurs when a bacterium picks up a piece of genetic material from its external environment and incorporates it into its own genome. Transduction is genetic transfer using a bacteriophage as a vector. Conjugation is direct gene transfer via sex pili.
The three main modes of genetic transfer for prokaryotes are transformation, transduction, and conjugation. Transformation occurs when a bacterium picks up a piece of genetic material from its external environment and incorporates it into its own genome. Transduction is genetic transfer using a bacteriophage as a vector. Conjugation is direct gene transfer via sex pili.
← Didn't Know|Knew It →
Which of the following characteristics make plasmid DNA useful for researchers?
Which of the following characteristics make plasmid DNA useful for researchers?
Tap to reveal answer
Plasmids are phenomenally useful for a number of reasons. They are capable of autonomous replication inside a suitable host (such as simple prokaryotes). Because they are non-genomic DNA (not located in the nucleus), plasmids are easily isolated and separated from the host's DNA. It is also relatively easy to insert cloned DNA into plasmid vectors. This allows for expression of recombinant proteins in prokaryotic cells.
Plasmids are phenomenally useful for a number of reasons. They are capable of autonomous replication inside a suitable host (such as simple prokaryotes). Because they are non-genomic DNA (not located in the nucleus), plasmids are easily isolated and separated from the host's DNA. It is also relatively easy to insert cloned DNA into plasmid vectors. This allows for expression of recombinant proteins in prokaryotic cells.
← Didn't Know|Knew It →
Which of the following is a unique characteristic of prokaryotic cells?
Which of the following is a unique characteristic of prokaryotic cells?
Tap to reveal answer
Prokaryotes lack a nuclear membrane, which allows translation to occur at the same time as transcription.
In eukaryotic cells the mRNA has to be exported to the cytoplasm before it can be translated. This transport requires post-transcriptional modification to protect the mRNA from degradation as it leaves the nucleus, a process unnecessary to prokaryotic cells. Both prokaryotes and eukaryotes can have cell walls and cytoplasts (cytoplasm). Prokaryotes do, in fact, generate proton gradients in order to complete cellular respiration. These gradients are created across the prokaryotic cell membrane, rather than across the mitochondrial membrane.
Prokaryotes lack a nuclear membrane, which allows translation to occur at the same time as transcription.
In eukaryotic cells the mRNA has to be exported to the cytoplasm before it can be translated. This transport requires post-transcriptional modification to protect the mRNA from degradation as it leaves the nucleus, a process unnecessary to prokaryotic cells. Both prokaryotes and eukaryotes can have cell walls and cytoplasts (cytoplasm). Prokaryotes do, in fact, generate proton gradients in order to complete cellular respiration. These gradients are created across the prokaryotic cell membrane, rather than across the mitochondrial membrane.
← Didn't Know|Knew It →
Which recombinant process depends on a F factor plasmid?
Which recombinant process depends on a F factor plasmid?
Tap to reveal answer
Beginning the process of conjugation requires the trait encoded by the F (fertility) plasmid. Transformation is the uptake of naked DNA, transduction is the transfer of genetic material via a virus, and translocation is the movement of a ribosome during protein translation.
Beginning the process of conjugation requires the trait encoded by the F (fertility) plasmid. Transformation is the uptake of naked DNA, transduction is the transfer of genetic material via a virus, and translocation is the movement of a ribosome during protein translation.
← Didn't Know|Knew It →
Which of the following is true of both bacterial conjugation and meiosis?
Which of the following is true of both bacterial conjugation and meiosis?
Tap to reveal answer
The only similarity between conjugation and meiosis is that both processes are types of sexual reproduction. Remember that sexual reproduction is characterized by the presence of genetic recombination (the ability to exchange genetic material between two DNA molecules). The result of both processes are daughter cells that are genetically unique from the parent cells.
In meiosis, genetic recombination occurs during crossing over in prophase I. In conjugation, genetic recombination occurs when the DNA from the donor bacterial cell is incorporated into the recipient bacterial cell. Only meiosis produces four daughter cells; conjugation produces only two.
The only similarity between conjugation and meiosis is that both processes are types of sexual reproduction. Remember that sexual reproduction is characterized by the presence of genetic recombination (the ability to exchange genetic material between two DNA molecules). The result of both processes are daughter cells that are genetically unique from the parent cells.
In meiosis, genetic recombination occurs during crossing over in prophase I. In conjugation, genetic recombination occurs when the DNA from the donor bacterial cell is incorporated into the recipient bacterial cell. Only meiosis produces four daughter cells; conjugation produces only two.
← Didn't Know|Knew It →
A bacterial cell must possess a gene on the in order to initiate conjugation.
A bacterial cell must possess a gene on the in order to initiate conjugation.
Tap to reveal answer
Conjugation is a form of sexual reproduction in bacterial cells. It involves formation of a bridge, called the sex pilus, between two bacterial cells. After sex pilus formation, the donor cell will pass genetic information to the recipient cell via the sex pilus. In order to initiate conjugation, a bacterial cell must contain the genes that code for the sex pilus, which are usually found on a specific plasmid. Recall that a plasmid contains the extrachromosomal DNA (found outside the bacterial cells’ chromosomes), whereas the nucleoid contains the chromosomal DNA. Sex pilus genes are always found on the plasmid, and can be passed from one cell to another during conjugation. This exchange increases the number of cells capable of forming the sex pilus, increasing the ability for bacterial cells to perform sexual reproduction and increase genetic variation.
Conjugation is a form of sexual reproduction in bacterial cells. It involves formation of a bridge, called the sex pilus, between two bacterial cells. After sex pilus formation, the donor cell will pass genetic information to the recipient cell via the sex pilus. In order to initiate conjugation, a bacterial cell must contain the genes that code for the sex pilus, which are usually found on a specific plasmid. Recall that a plasmid contains the extrachromosomal DNA (found outside the bacterial cells’ chromosomes), whereas the nucleoid contains the chromosomal DNA. Sex pilus genes are always found on the plasmid, and can be passed from one cell to another during conjugation. This exchange increases the number of cells capable of forming the sex pilus, increasing the ability for bacterial cells to perform sexual reproduction and increase genetic variation.
← Didn't Know|Knew It →
Which of the following is false about conjugation?
I. It is a form of sexual reproduction
II. It forms a bridge between two bacterial cells; the bridge is called a plasmid
III. It involves transport of genetic material via vectors
Which of the following is false about conjugation?
I. It is a form of sexual reproduction
II. It forms a bridge between two bacterial cells; the bridge is called a plasmid
III. It involves transport of genetic material via vectors
Tap to reveal answer
Bacterial cells are capable of conjugation, a form of sexual reproduction. The process involves the formation of a bridge between bacterial cells that facilitates the movement of genetic material from one cell to the other. This bridge is called a sex pilus. A plasmid is a circular extrachromosomal DNA fragment. To initiate conjugation, a bacterium must possess a plasmid that enables formation of the sex pilus.
Bacterial cells can also exchange genetic material indirectly via viral vectors (certain bacteriophages) that carry bacterial genetic information from one cell to another; however, this does not occur in conjugation. It occurs in another form of sexual reproduction called transduction.
Bacterial cells are capable of conjugation, a form of sexual reproduction. The process involves the formation of a bridge between bacterial cells that facilitates the movement of genetic material from one cell to the other. This bridge is called a sex pilus. A plasmid is a circular extrachromosomal DNA fragment. To initiate conjugation, a bacterium must possess a plasmid that enables formation of the sex pilus.
Bacterial cells can also exchange genetic material indirectly via viral vectors (certain bacteriophages) that carry bacterial genetic information from one cell to another; however, this does not occur in conjugation. It occurs in another form of sexual reproduction called transduction.
← Didn't Know|Knew It →
Which of the following molecules will you least likely find in a plasmid structure?
Which of the following molecules will you least likely find in a plasmid structure?
Tap to reveal answer
A plasmid is a circular DNA molecule that is found outside the bacterial nucleoid (chromosomal DNA). DNA, or deoxyribonucleic acid, is a type of nucleic acid; therefore, a plasmid must contain substances that make up a nucleic acid. Recall that nucleic acids are made up of three main molecules per monomer: a pentose sugar, a phosphate group, and a nitrogenous base (adenine, thymine, uracil, guanine, or cytosine). Like the nucleoid DNA, plasmid DNA will be made of nucleotide monomers that contain a deoxyribose sugar, a phosphate, and a nitrogenous base.
Glycerol is the three carbon backbone for phospholipid and triglyceride structures. In triglycerides, a fatty acid chain is bound to each of the three glycerol carbons, whereas in phospholipids, two carbons are bound to fatty acids and the third is bound to a phosphate group. Glycerol is a chief structural component of lipid molecules, but will not be found in a nucleic acid plasmid.
A plasmid is a circular DNA molecule that is found outside the bacterial nucleoid (chromosomal DNA). DNA, or deoxyribonucleic acid, is a type of nucleic acid; therefore, a plasmid must contain substances that make up a nucleic acid. Recall that nucleic acids are made up of three main molecules per monomer: a pentose sugar, a phosphate group, and a nitrogenous base (adenine, thymine, uracil, guanine, or cytosine). Like the nucleoid DNA, plasmid DNA will be made of nucleotide monomers that contain a deoxyribose sugar, a phosphate, and a nitrogenous base.
Glycerol is the three carbon backbone for phospholipid and triglyceride structures. In triglycerides, a fatty acid chain is bound to each of the three glycerol carbons, whereas in phospholipids, two carbons are bound to fatty acids and the third is bound to a phosphate group. Glycerol is a chief structural component of lipid molecules, but will not be found in a nucleic acid plasmid.
← Didn't Know|Knew It →
Which of the following is false regarding plasmids?
Which of the following is false regarding plasmids?
Tap to reveal answer
Plasmids are circular, double-stranded DNA molecules found outside the nucleoid (extrachomosomal DNA). They can serve a variety of functions and code for traits that may vary within a single species, since different individuals may carry different plasmids.
Most notable are the plasmids related to antibiotic resistance and plasmids required for formation of the sex pilus in conjugation. Recall that antibiotic resistance is the ability of a bacterial cell to survive in the presence of antibiotics. This ability is facilitated by antibiotic resistant proteins that are coded by certain genes found on the plasmid of a bacterial cell.
Plasmids are circular, double-stranded DNA molecules found outside the nucleoid (extrachomosomal DNA). They can serve a variety of functions and code for traits that may vary within a single species, since different individuals may carry different plasmids.
Most notable are the plasmids related to antibiotic resistance and plasmids required for formation of the sex pilus in conjugation. Recall that antibiotic resistance is the ability of a bacterial cell to survive in the presence of antibiotics. This ability is facilitated by antibiotic resistant proteins that are coded by certain genes found on the plasmid of a bacterial cell.
← Didn't Know|Knew It →
Viruses can infect host cells by incorporating themselves into the host cell’s genome. Based on this information, what will you most likely find in a virus?
Viruses can infect host cells by incorporating themselves into the host cell’s genome. Based on this information, what will you most likely find in a virus?
Tap to reveal answer
The question states that a virus infects a host cell by integrating with the host cell’s genome; therefore, the virus integrates with the chromosomes inside the nucleus of the host cell. Recall that both plasmids and episomes are extrachromosomal DNA molecules (DNA molecules found outside the chromosomes), however, only episomes can integrate with the chromosomes inside the nucleus of a host cell. This means that a virus will only be able to infect host cells if it contains an episome. Plasmids are only found in bacteria and cannot integrate with chromosomal DNA.
The question states that a virus infects a host cell by integrating with the host cell’s genome; therefore, the virus integrates with the chromosomes inside the nucleus of the host cell. Recall that both plasmids and episomes are extrachromosomal DNA molecules (DNA molecules found outside the chromosomes), however, only episomes can integrate with the chromosomes inside the nucleus of a host cell. This means that a virus will only be able to infect host cells if it contains an episome. Plasmids are only found in bacteria and cannot integrate with chromosomal DNA.
← Didn't Know|Knew It →
What is the structure in prokaryotic cells that often holds antibiotic resistance genes?
What is the structure in prokaryotic cells that often holds antibiotic resistance genes?
Tap to reveal answer
Antibiotic resistance genes are often found on plasmids, which are small DNA molecules which are easily transfered to other prokaryotic cells.
Antibiotic resistance genes are often found on plasmids, which are small DNA molecules which are easily transfered to other prokaryotic cells.
← Didn't Know|Knew It →
In a small village, a doctor over-prescribed Ciprofloxin (an antiobiotic) to his patients. The result was that the majority of his patients had developed a new strain of bacteria that had become resistant to Ciprofloxin.
What is a possible route that may have caused these bacteria to become antibiotic resistant?
In a small village, a doctor over-prescribed Ciprofloxin (an antiobiotic) to his patients. The result was that the majority of his patients had developed a new strain of bacteria that had become resistant to Ciprofloxin.
What is a possible route that may have caused these bacteria to become antibiotic resistant?
Tap to reveal answer
Antibiotic resistant genes are commonly transferred through plasmids. Plasmids are small, circular, extra-chromosomal pieces of DNA that contain supplemental genes, which can be passed from bacteria to bacteria.
Antibiotic resistant genes are commonly transferred through plasmids. Plasmids are small, circular, extra-chromosomal pieces of DNA that contain supplemental genes, which can be passed from bacteria to bacteria.
← Didn't Know|Knew It →
Which of these processes is the means by which a bacterium can directly uptake and incorporate foreign DNA from the environment into its genome?
Which of these processes is the means by which a bacterium can directly uptake and incorporate foreign DNA from the environment into its genome?
Tap to reveal answer
Transformation is defined as the process by which bacteria can incorporate exogenous DNA from the environment into their genome via direct uptake. Transduction and conjugation are also processes by which exogenous DNA is incorporated, but involve other methods.
Transformation is defined as the process by which bacteria can incorporate exogenous DNA from the environment into their genome via direct uptake. Transduction and conjugation are also processes by which exogenous DNA is incorporated, but involve other methods.
← Didn't Know|Knew It →