Biology Chapter 2: Protein Production

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Questions and Answers

What is the ultimate purpose of THF synthesis in the bacterial cell?

Cell wall formation

Energy production

Protein synthesis

Deoxynucleotide synthesis (correct)

Why is the THF synthesis pathway a target for antimicrobial compounds?

It is involved in energy production

It is unique to bacterial cells (correct)

It is essential for human cells

It is not targeted by the immune system

What is the primary function of the enzyme DNA polymerase?

Breaking down proteins

Replicating the bacterial chromosome (correct)

Synthesizing THF

Regulating supercoiling of DNA

What is the result of twisting one end of DNA while holding the other end fixed?

Formation of supercoils Signup and view all the answers

What is the normal number of nucleotide pairs per helical turn in relaxed DNA?

10 Signup and view all the answers

What is the purpose of topoisomerases?

Regulating supercoiling of DNA Signup and view all the answers

What is the rate of mRNA synthesis by bacterial RNA polymerase under ideal conditions?

55 nucleotides per second Signup and view all the answers

What is the main difference between bacterial and eukaryotic RNA polymerase in terms of transcription initiation?

Eukaryotic RNA polymerase requires additional transcription factors Signup and view all the answers

What is the consequence of having a chromosome composed of helical DNA?

Formations of supercoils Signup and view all the answers

What is the result of increasing or decreasing the number of nucleotide pairs per helical turn?

Additional stress on the DNA molecule Signup and view all the answers

What is the structural characteristic of bacterial RNA polymerase?

It consists of five subunits Signup and view all the answers

What is the significance of the differences between bacterial and eukaryotic RNA polymerase?

They make the enzyme complex an ideal target for antimicrobial compounds Signup and view all the answers

What is the role of RNA polymerase in the cell?

To transcribe mRNA from DNA Signup and view all the answers

What is the characteristic of eukaryotic RNA polymerase in terms of its size?

It is larger than bacterial RNA polymerase Signup and view all the answers

What is the enzyme complex responsible for transcribing DNA into RNA in bacterial cells?

RNA polymerase Signup and view all the answers

What is the name of the RNA molecule synthesized during the transcription process?

mRNA Signup and view all the answers

What is the source of energy used to power the transcription process?

Nucleoside triphosphates Signup and view all the answers

What is the process by which the information in the DNA of a bacterial gene is used to synthesize an RNA molecule?

Transcription Signup and view all the answers

What is the role of RNA polymerase in bacterial cells?

To synthesize mRNA Signup and view all the answers

What is the result of the transcription process in bacterial cells?

An mRNA molecule is synthesized Signup and view all the answers

What is the relationship between the DNA molecule and the mRNA molecule in bacterial cells?

The mRNA molecule is synthesized from the DNA molecule Signup and view all the answers

What is the purpose of the proton motive force in bacterial cells?

To transport nutrients into the cell Signup and view all the answers

What is the name of the enzyme complex responsible for transcribing DNA into RNA in bacterial cells?

RNA polymerase Signup and view all the answers

What is the process by which the information in the DNA of a bacterial gene is used to synthesize an RNA molecule?

Transcription Signup and view all the answers

What is the name of the RNA molecule synthesized during the transcription process?

mRNA Signup and view all the answers

What is the energy source used to power the transcription process?

Proton motive force Signup and view all the answers

What is the role of RNA polymerase in the transcription process?

To synthesize RNA from DNA Signup and view all the answers

What is the result of the transcription process in bacterial cells?

Synthesis of RNA Signup and view all the answers

What is the relationship between the DNA molecule and the mRNA molecule in bacterial cells?

mRNA is synthesized from DNA Signup and view all the answers

What is the purpose of the proton motive force in bacterial cells?

To power important cellular processes Signup and view all the answers

What is the function of RNA polymerase in the cell?

To transcribe DNA into RNA Signup and view all the answers

What is the rate of mRNA synthesis by bacterial RNA polymerase under ideal conditions?

55 nucleotides per second Signup and view all the answers

What is a key difference between bacterial and eukaryotic RNA polymerase?

Bacterial RNA polymerase requires the help of additional transcription factors Signup and view all the answers

What is the structural characteristic of bacterial RNA polymerase?

It has five subunits Signup and view all the answers

Why is RNA polymerase an ideal target for antimicrobial compounds?

Because it is essential for bacterial growth Signup and view all the answers

What is the size of bacterial RNA polymerase?

90 × 90 × 160 angstroms Signup and view all the answers

What is the precursor of THF that humans readily absorb from their diet?

Folate Signup and view all the answers

What is the enzyme responsible for replicating the bacterial chromosome?

DNA polymerase Signup and view all the answers

What is the consequence of twisting one end of DNA while holding the other end fixed?

Formation of supercoils Signup and view all the answers

What is the normal number of nucleotide pairs per helical turn in relaxed DNA?

10 Signup and view all the answers

What is the function of topoisomerases?

To regulate supercoiling of DNA Signup and view all the answers

What is the result of increasing or decreasing the number of nucleotide pairs per helical turn?

Formation of supercoils Signup and view all the answers

What is the role of dihydropteroate synthase in bacterial cells?

To synthesize THF Signup and view all the answers

What is the consequence of having a chromosome composed of helical DNA?

Formation of supercoils Signup and view all the answers

What is unique about the size of glycopeptide antibiotics?

They are extremely large peptides. Signup and view all the answers

Why are glycopeptide antibiotics often given intravenously?

They are poorly absorbed in the gastrointestinal tract. Signup and view all the answers

What type of organisms are glycopeptide antibiotics most effective against?

Gram-positive bacteria Signup and view all the answers

Which of the following is a limitation of glycopeptide antibiotics?

They are not effective against gram-negative bacteria. Signup and view all the answers

What is the coverage of vancomycin and telavancin against staphylococci and streptococci?

Nearly universal coverage against staphylococci and streptococci. Signup and view all the answers

Why should vancomycin not be used to treat L. monocytogenes infections?

Clinical failures have been reported with vancomycin. Signup and view all the answers

What type of bacteria is colistin effective against?

Aerobic gram-negative bacteria Signup and view all the answers

What is a side effect of colistin toxicity?

Both A and B Signup and view all the answers

What is the mechanism of action of colistin?

Binds to and disrupts the bacterial outer membrane Signup and view all the answers

Why was colistin not used frequently in the past?

It was toxic Signup and view all the answers

What type of bacteria is colistin not effective against?

Proteus spp. Signup and view all the answers

What is the primary use of colistin?

Treatment of bacterial infections Signup and view all the answers

What is a characteristic of colistin?

It lacks activity against Proteus spp. Signup and view all the answers

What is the significance of colistin?

It is useful in the treatment of infections caused by aerobic gram-negative bacteria Signup and view all the answers

What type of lactone ring does clarithromycin consist of?

14-member macrocyclic lactone ring Signup and view all the answers

What type of bacteria is clarithromycin active against?

Both gram-positive and gram-negative bacteria Signup and view all the answers

Which of the following bacteria is clarithromycin active against?

Haemophilus influenzae Signup and view all the answers

What type of organisms is clarithromycin active against, in addition to bacteria?

Atypical bacteria and spirochetes Signup and view all the answers

Which of the following is NOT a type of bacteria that clarithromycin is active against?

Escherichia coli Signup and view all the answers

What is the advantage of clarithromycin compared to erythromycin?

It has somewhat greater activity against aerobic gram-positive bacteria and H. influenzae Signup and view all the answers

What is the type of lactone ring that erythromycin consists of?

14-member macrocyclic lactone ring Signup and view all the answers

What is the class of antibiotics that clarithromycin belongs to?

Macrolides Signup and view all the answers

What class of antibiotics does tigecycline belong to?

Tetracyclines Signup and view all the answers

What is the characteristic of tigecycline?

Broad-spectrum antibiotic Signup and view all the answers

Which of the following bacteria is susceptible to tigecycline?

Streptococcus pyogenes Signup and view all the answers

What type of bacteria is Haemophilus influenzae?

Gram-negative Signup and view all the answers

Which of the following is NOT susceptible to tigecycline?

Mycobacterium tuberculosis Signup and view all the answers

What type of bacteria is Listeria monocytogenes?

Gram-positive Signup and view all the answers

Which of the following is an anaerobic bacterium susceptible to tigecycline?

Bacteroides fragilis Signup and view all the answers

What is the characteristic of tigecycline compared to other antibiotics?

Broader spectrum of activity Signup and view all the answers

What is a potential consequence of using clindamycin?

Life-threatening colitis Signup and view all the answers

What is the origin of the name 'lincosamide antibiotics'?

From the site where the bacterium was isolated Signup and view all the answers

What is the significance of Streptomyces spp.?

They are bacteria that produce antibiotics Signup and view all the answers

What is a characteristic of clindamycin?

It is active against anaerobic bacteria Signup and view all the answers

What is a potential consequence of resistance to clindamycin?

Resistance to other antibiotics Signup and view all the answers

What is the name of the antibiotic that was first isolated from a bacterium found in Lincoln, Nebraska?

Lincomycin Signup and view all the answers

What is the significance of the study by Falagas et al. (1995)?

It compared the efficacy of clindamycin and metronidazole Signup and view all the answers

What is the name of the bacterium that produces lincomycin?

Streptomyces spp. Signup and view all the answers

Study Notes

Protein Production

Protein production in bacteria involves DNA transcription and translation, resulting in the creation of a protein.
Energy from fuel consumption is harnessed and stored in nucleoside triphosphates and the proton motive force, which powers important processes like active transport and ATP generation.

Transcription

Transcription is the process by which DNA information is used to synthesize messenger RNA (mRNA).
RNA polymerase binds to DNA and uses it as a template to add ribonucleic acids to a corresponding mRNA molecule.
Bacterial RNA polymerase is distinct from eukaryotic RNA polymerase, with differences in structure and function.
Bacterial RNA polymerase can make mRNA at a rate of 55 nucleotides per second.

RNA Polymerase

Bacterial RNA polymerase consists of five subunits and has dimensions of approximately 90 × 90 × 160 angstroms.
Eukaryotic RNA polymerase has many more subunits and has dimensions of 140 × 136 × 110 angstroms.
Bacterial RNA polymerase can initiate transcription alone, whereas eukaryotic RNA polymerase requires additional transcription factors.

Tetrahydrofolate (THF) Synthesis

THF is required for the synthesis of several nucleotides.
Humans can absorb folate, a precursor of THF, from their diet, but most bacteria cannot and must synthesize it.
The synthetic pathway of THF is an attractive target for antimicrobial compounds.

DNA Synthetic Enzymes

DNA polymerase is responsible for replicating the bacterial chromosome, but other enzymes are also required.
Topoisomerases regulate supercoiling, or twisting of the DNA, to accommodate the stress on the DNA molecule.
Supercoiling results in the formation of additional nucleotide pairs per helical turn, which is accommodated by the formation of supercoils.

Protein Production

Protein production in bacteria involves DNA transcription and translation, resulting in the creation of a protein.
Energy from fuel consumption is harnessed and stored in nucleoside triphosphates and the proton motive force, which powers important processes like active transport and ATP generation.

Transcription

Transcription is the process by which DNA information is used to synthesize messenger RNA (mRNA).
RNA polymerase binds to DNA and uses it as a template to add ribonucleic acids to a corresponding mRNA molecule.
Bacterial RNA polymerase is distinct from eukaryotic RNA polymerase, with differences in structure and function.
Bacterial RNA polymerase can make mRNA at a rate of 55 nucleotides per second.

RNA Polymerase

Bacterial RNA polymerase consists of five subunits and has dimensions of approximately 90 × 90 × 160 angstroms.
Eukaryotic RNA polymerase has many more subunits and has dimensions of 140 × 136 × 110 angstroms.
Bacterial RNA polymerase can initiate transcription alone, whereas eukaryotic RNA polymerase requires additional transcription factors.

Tetrahydrofolate (THF) Synthesis

THF is required for the synthesis of several nucleotides.
Humans can absorb folate, a precursor of THF, from their diet, but most bacteria cannot and must synthesize it.
The synthetic pathway of THF is an attractive target for antimicrobial compounds.

DNA Synthetic Enzymes

DNA polymerase is responsible for replicating the bacterial chromosome, but other enzymes are also required.
Topoisomerases regulate supercoiling, or twisting of the DNA, to accommodate the stress on the DNA molecule.
Supercoiling results in the formation of additional nucleotide pairs per helical turn, which is accommodated by the formation of supercoils.

Glycopeptide Antibiotics

Glycopeptide antibiotics are peptides with sugar moieties attached to them.
Examples of glycopeptide antibiotics include vancomycin and telavancin.
These antibiotics are poorly absorbed in the gastrointestinal tract and must be given intravenously to treat systemic infections.
They are extremely large and unable to pass through porins in the outer membranes of gram-negative bacteria, restricting their activity to gram-positive organisms.
Vancomycin and telavancin are active against nearly all staphylococci and streptococci, including methicillin-resistant staphylococci and strains of penicillin-resistant S. pneumoniae.
Susceptibility among enterococci is now variable.

Colistin

Colistin has activity against many aerobic gram-negative bacteria, including P. aeruginosa, E. coli, and Klebsiella spp.
Many multidrug-resistant strains of these bacteria remain susceptible to colistin.
Colistin lacks activity against other gram-negative bacteria, gram-positive bacteria, and anaerobic bacteria.
The toxicity of colistin has been found to be less than previously believed, but it is still associated with nephrotoxicity and neurotoxicity.

Macrolides

Macrolides are active against gram-positive bacteria, including some Streptococcus pyogenes, viridans streptococci, and Staphylococcus aureus.
They are also active against gram-negative bacteria, including Neisseria spp. and Haemophilus influenzae.
Macrolides are active against atypical bacteria, including Chlamydia spp., Mycoplasma spp., and Legionella pneumophila.
Clarithromycin is a semisynthetic derivative of erythromycin with greater activity against aerobic gram-positive bacteria and H. influenzae.

Tigecycline

Tigecycline is a glycylcycline antibiotic with broad activity against aerobic and anaerobic bacteria.
It is active against gram-positive bacteria, including Streptococcus pyogenes, viridans group streptococci, and Staphylococcus aureus.
Tigecycline is also active against gram-negative bacteria, including Haemophilus influenzae and Neisseria spp.
It is active against atypical bacteria, including Mycoplasma spp.
Caution must be exercised regarding the relatively frequent occurrence of C. difficile colitis associated with its use.

Clindamycin

Clindamycin is active against many aerobic and anaerobic bacteria.
Resistance to erythromycin may also lead to resistance to clindamycin in some bacteria.
Use of clindamycin may lead to life-threatening C. difficile colitis.

Lincosamide Antibiotics

The class of lincosamide antibiotics received its name from the site where the bacterium that produced lincomycin was isolated: Lincoln, Nebraska.
Lincomycin is a new antibiotic with biologic properties.

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Description

This quiz covers the basics of protein production, including DNA transcription, RNA, and ribonucleic acids. Test your understanding of the biological processes involved.