Micro Exam 2 First Few Lectures

During the glycolysis pathway, glucose is converted to pyruvate. This process requires the input of two high-energy phosphates, which are derived from two molecules of ATP. Therefore, the correct answer is "2 phosphate ; 4 ATP." This means that two molecules of high-energy phosphate are used, and in return, four molecules of ATP are produced.

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B-Lactamase is the correct answer because it is an enzyme produced by certain bacteria that can break down the structure of penicillin and other beta-lactam antibiotics. This enzyme acts as a defense mechanism for the bacteria, allowing them to resist the effects of the antibiotic. By breaking down the beta-lactam ring present in penicillin, B-Lactamase renders the antibiotic ineffective, leading to antibiotic resistance.

Efflux pump is the correct answer because it is a mechanism by which bacteria can develop resistance to tetracycline. Efflux pumps are proteins that are able to pump out tetracycline from inside the bacterial cell, preventing it from reaching its target and exerting its antimicrobial effect. This allows the bacteria to survive and continue to grow even in the presence of tetracycline. Other options like B-Lactamase, Methylase, and Altering Enzyme are not directly associated with resistance to tetracycline.

Respiration is the correct answer because it involves the oxidation of NADH+H+ in the electron transport system. During respiration, NADH+H+ is oxidized to NAD+ as it donates its electrons to the electron transport chain. This process generates energy in the form of ATP. Fermentation, on the other hand, does not involve the electron transport system and instead uses an organic molecule as the final electron acceptor. Dimerization and alkylization are not related to the oxidation of NADH+H+ in the electron transport system.

The sterne vaccine strain is a strain of Bacillus anthracis that is used as a vaccine against anthrax. It is derived from a strain that lacks the pXO2 plasmid, which is responsible for the production of the protective antigen component of the anthrax toxin. This plasmid is essential for the virulence of the bacteria, so by lacking it, the sterne vaccine strain is avirulent and can be used safely as a vaccine.

Transposase is the correct answer because it is an enzyme that catalyzes the movement of transposable elements, such as IS elements, from one location to another within the genome. Transposase recognizes specific sequences at the ends of the transposable element and cuts the DNA, allowing the element to be inserted into a new site. This process, known as transposition, is important for genetic diversity and can have significant effects on the structure and function of genomes.

Insertion sequences are short segments of DNA that can move around within a genome. They typically contain inverted repeat DNA sequences at their ends. These inverted repeats serve as recognition sites for the enzymes that catalyze the insertion of the sequence into the genome. Therefore, the statement that insertion sequences have inverted repeat DNA sequences at their ends is true.

Pentoses and citrate are both important in gluconeogenesis because they can be converted into glycitic intermediates. These intermediates are necessary for the production of glucose, which is used for various biosynthetic processes in the body. Therefore, it is true that pentoses and citrate allow gluconeogenesis to produce the glycitic intermediates needed for biosynthetic purposes.

Elongation is not a major way in which bacteria transfer genes. Transformation, transduction, and conjugation are the three main mechanisms through which bacteria can transfer genetic material. Elongation, on the other hand, refers to the process of adding amino acids to a growing protein chain during protein synthesis, and is not involved in gene transfer.

SCCmec Type IV is not an example of a hospital-acquired infection. SCCmec is a genetic element found in certain strains of Staphylococcus aureus, including MRSA (methicillin-resistant Staphylococcus aureus). MRSA, on the other hand, is a type of bacteria that causes hospital-acquired infections. Therefore, MRSA is the correct answer as an example of a hospital-acquired infection.

To deal with acid production bacteria can:
neutral products (formed by the neutralization of acid end products)
stop growing
alternate acid and alchol production
be acid tolerant

Sugar metabolism is an important diagnostic for the classification of pathogenic bacteria because different bacteria have different abilities to metabolize sugars. By studying how bacteria metabolize sugars, scientists can identify and classify different types of bacteria. This information is crucial for diagnosing and treating bacterial infections, as different bacteria may require different antibiotics or treatment approaches. Therefore, the statement "Sugar metabolism is an important diagnostic for the classification of pathogenic bacteria" is true.

Streptogramins block the P site on the ribosome.

Most are neutrophiles or acidophiles

Slippage during replication is a phenomenon that occurs when DNA strands misalign during the replication process, leading to the insertion or deletion of nucleotides. Opa genes, which are found in certain bacteria, have been shown to contribute to slippage during replication. Therefore, it is correct to say that slippage during replication is due to Opa genes.

Both aerobic and anaerobic can

The oxidase test is used to determine if bacteria have cytochromes that can be used in respiration. Cytochromes are proteins that contain heme groups and are involved in electron transport during respiration. The oxidase test detects the presence of cytochrome c oxidase, which is an enzyme involved in the electron transport chain. If the bacteria produce cytochrome c oxidase, then they will produce a positive result in the oxidase test. This test is commonly used to differentiate between different groups of bacteria, such as Gram-negative bacteria that are oxidase-positive and Gram-positive bacteria that are oxidase-negative.

The Nitrate Reductase Test is used to determine if nitrate can be used as a final electron acceptor in respiration. This test involves adding nitrate to a bacterial culture and observing for the presence of nitrite. If nitrite is present, it indicates that the bacteria have the enzyme nitrate reductase, which can convert nitrate to nitrite. This enzyme is necessary for bacteria to use nitrate as an electron acceptor in respiration. Therefore, the Nitrate Reductase Test is the appropriate test to determine if nitrate can be used as a final electron acceptor.

Transduction is the correct answer because it is a process by which genetic material is transferred from one bacterium to another by a bacteriophage (a virus that infects bacteria). During transduction, the bacteriophage injects its DNA into the bacterial cell, and this DNA is resistant to DNAse, an enzyme that breaks down DNA. Therefore, transduction is the only option that is DNAse resistant.

The catalase test involves the use of a mixture of 3% H2O2 (hydrogen peroxide) and the observation of bubble formation. This test is used to determine the presence of the enzyme catalase in bacteria. Catalase is responsible for breaking down hydrogen peroxide into water and oxygen gas, resulting in the formation of bubbles. Therefore, the correct answer is the Catalase Test.

The statement is false because S. pneumonia strains that lack a capsule are actually avirulent, meaning they are not capable of causing disease. The capsule is a crucial virulence factor for S. pneumoniae as it helps the bacteria evade the host immune system and establish infection. Without a capsule, the bacteria are more susceptible to immune clearance and are unable to cause disease.

The catalase test is used to determine the presence of catalase enzyme in bacteria, which breaks down hydrogen peroxide into water and oxygen. When hydrogen peroxide is added to a bacterial culture, the presence of bubbles indicates the production of oxygen gas as a result of catalase activity. Therefore, the correct answer is Oxygen.

Alanine is not a source of NH3 used by bacteria. NH3 is typically produced by the breakdown of amino acids such as arginine, urea, and tryptophan. N2 fixation is also a process by which bacteria convert atmospheric nitrogen into NH3. However, alanine does not release NH3 when metabolized by bacteria.

Aminoglycosides, specifically streptomycin, interact with the 30s subunit of the ribosome. This interaction prevents the binding of f-Met, which is the first amino acid residue of most bacterial proteins. By inhibiting this binding, aminoglycosides disrupt protein synthesis in bacteria, leading to their death. Methotrexate, Rifampin, and Lipiarmycin do not have this specific mechanism of action and do not interact with the 30s subunit of the ribosome in the same way.

They dont because they need a strong motor force to be transported

Doesn't matter what type as long as they are aerobic

In a disk diffusion assay, a sensitive antibiotic resistance indicates that the antibiotics are being inhibited or killed by 1/4 of the achievable clinical dose. This means that the concentration of the antibiotic required to inhibit or kill the bacteria is only 1/4th of what would normally be used in a clinical setting. This suggests that the bacteria are highly susceptible to the antibiotic and that a lower dose can be effective in treating the infection.

Interact with the 50S subunit and inhibit the formation of peptide bonds

Tetracycline is the correct answer because it is known to interact with the 16s rRNA in the 30s subunit of the bacterial ribosome. This interaction blocks the transfer of tRNAs to the acceptor site, ultimately inhibiting protein synthesis in bacteria. Tetracycline is a broad-spectrum antibiotic commonly used to treat various bacterial infections.

Lysogenic phages are bacteriophages that can integrate their DNA into the host bacterium's genome and remain dormant for a period of time. When they are activated, they can enter the lytic cycle and cause the host cell to burst, releasing new phages. Turbid plaques are formed when lysogenic phages infect bacteria, as the host cells continue to grow and divide even after phage integration. This results in a cloudy appearance in the area where the phages have infected the bacteria.

Natural antibiotic resistance mechanisms refer to the inherent ability of certain bacteria to resist the effects of antibiotics. This resistance is not acquired or developed over time but is a natural characteristic of the bacteria. It can be a result of various factors such as the presence of efflux pumps that can actively remove antibiotics from the bacterial cell, the impermeability of the bacterial cell wall to certain antibiotics, or the production of enzymes that can inactivate antibiotics. These natural resistance mechanisms make the bacteria inherently more resistant to antibiotics and can pose challenges in the treatment of bacterial infections.

The activation of the Lambda Repressor in E. Coli keeps the phage quiescent. This means that it prevents the phage from becoming active or replicating within the host cell. By keeping the phage quiescent, the Lambda Repressor helps maintain a dormant state, preventing the phage from causing harm or lysing the host cell.

Acquired antibiotic resistance refers to the type of resistance that is obtained from other bacteria through the transfer of mobile genetic elements. This means that bacteria can acquire resistance genes from other bacteria in their environment, allowing them to survive and proliferate in the presence of antibiotics. This transfer can occur through processes such as conjugation, transformation, or transduction. Acquired resistance is an important mechanism by which bacteria can develop resistance to antibiotics, leading to the emergence of multidrug-resistant strains.

Fosfomycin inhibits the formation of NAM (N-acetylmuramic acid). NAM is an essential component of the bacterial cell wall, specifically in the peptidoglycan layer. By inhibiting the formation of NAM, fosfomycin disrupts the synthesis of the bacterial cell wall, leading to cell death. This makes fosfomycin an effective antibiotic against a wide range of bacteria.

The statement is incorrect. An efflux pump is a mechanism used by bacteria to remove toxic substances from their cytoplasm, not to cause an influx of bacterial concentration. Therefore, the correct answer is False.

Macrolides and streptogramins Lincosamindes, such as Clindamycin, interact with the 23s rRNA in the 50s subunit of the bacterial ribosome. This interaction inhibits the translocation process, which is necessary for the movement of the ribosome along the mRNA strand during protein synthesis. As a result, the growing peptide chain is unable to be released from the ribosome, leading to the inhibition of bacterial protein synthesis.

Conjugation is a process in which genetic material is transferred between bacterial cells through direct contact. It requires physical contact between cells, typically facilitated by a structure called a pilus. Therefore, the statement that conjugation can occur by cells in the same relative vicinity with no touch is false.

Donor and recipient

Conjugation is a process by which genetic material is transferred between bacterial cells. DNase is an enzyme that breaks down DNA. The statement suggests that conjugation is affected by DNase, implying that DNase can inhibit or interfere with the process. However, this is not true. Conjugation is not sensitive to DNase, and the presence of DNase does not prevent or hinder the transfer of genetic material between bacterial cells.

Trimethoprim is an antibiotic that binds dihydrofolate reducatase thus inhibiting the THFA biosynthetic pathway

The oxidation of NADH+ H+ by the reduction of pyruvate is called fermentation. In this process, NADH+ H+ is oxidized, releasing energy, while pyruvate is reduced. Fermentation is an anaerobic process that occurs in the absence of oxygen. It is commonly observed in microorganisms and some types of cells, such as muscle cells, when oxygen is limited or unavailable. Fermentation is an important metabolic pathway that allows cells to continue producing ATP, the energy currency of the cell, in the absence of oxygen.

Erythromycin is an antibiotic that works by inhibiting protein synthesis in bacteria. The target of erythromycin is the ribosome, which is the cellular machinery responsible for protein synthesis. By binding to the ribosome, erythromycin prevents the formation of new proteins, ultimately leading to the inhibition of bacterial growth and the eradication of the infection.

Tetracyclines target the ribosome. Ribosomes are cellular structures responsible for protein synthesis. Tetracyclines bind to the ribosomes, specifically to the 30S subunit, and inhibit the attachment of aminoacyl-tRNA to the A site, preventing the elongation of the protein chain. This ultimately leads to the inhibition of bacterial protein synthesis, making tetracyclines effective against certain bacterial infections.

Methylase is the correct answer because it is an enzyme that adds a methyl group to the 23S rRNA component of the bacterial ribosome. This modification prevents erythromycin from binding to the ribosome and inhibiting protein synthesis, thereby causing resistance to the antibiotic. Methylase alters the target site of erythromycin, making it ineffective in inhibiting bacterial growth.

Altering enzymes are responsible for causing resistance to form from streptomycin. These enzymes modify the target site of the antibiotic, preventing it from binding effectively and inhibiting the growth of bacteria. This alteration allows the bacteria to continue growing and reproducing, leading to resistance against streptomycin.

The complete holoenzyme consists of the aaBB' subunit and the sigma factor. The aaBB' subunit is responsible for the catalytic activity of the enzyme, while the sigma factor is involved in recognizing the promoter region of DNA and initiating transcription. Therefore, the combination of aaBB' and sigma is required for the full functionality of the holoenzyme in transcription.

They are the main source

MacConkey's agar is selective (contains bile salts and crystal violet) and differential (lactose fermenters form red colonies)

Mannitol Salt Agar is selective (7.5% NaCL = halotolerant) and differential (mannitol fermenters produce acd)

Transformation is the process by which S. Pneumonia takes up foreign genetic material from its surroundings and incorporates it into its own genome. This allows for the exchange of genetic information and can result in the acquisition of new traits or resistance to antibiotics. Transduction, conjugation, and elongation are not specific steps of S. Pneumonia's transformation process.