Microbiology Chapter 3 Classification

Gonorrhea is caused by the bacterium Neisseria. Neisseria gonorrhoeae is a sexually transmitted bacterium that infects the mucous membranes of the reproductive system, throat, rectum, and eyes. It is primarily transmitted through sexual contact, including vaginal, oral, and anal sex. Neisseria gonorrhoeae can cause symptoms such as painful urination, discharge from the genitals, and in some cases, no symptoms at all. If left untreated, gonorrhea can lead to serious complications such as pelvic inflammatory disease, infertility, and an increased risk of HIV transmission.

Nucleic acid hybridization involves the degree at which DNA will form a double-stranded helix relating to their relatedness. This technique allows scientists to determine the similarity or relatedness between two DNA samples by measuring the extent to which they can bind together. By heating and cooling the DNA samples, they can be denatured and then allowed to re-anneal, forming double-stranded helices if they are related. This process is used in various applications, such as genetic testing, DNA sequencing, and forensic analysis.

Catalase positive and catalase negative refer to the ability of a microorganism to produce the enzyme catalase, which breaks down hydrogen peroxide into water and oxygen. Alpha-hemolytic and beta-hemolytic refer to the types of hemolysis produced by certain bacteria when grown on blood agar. Both of these characteristics are examples of biochemical tests, which are used to identify and classify microorganisms based on their metabolic capabilities and chemical reactions.

Phage typing is the correct answer because it involves the identification of a bacterium by testing its susceptibility to specific bacteriophages. Bacteriophages are viruses that infect bacteria, and different strains of bacteria can have different susceptibility patterns to specific phages. By exposing a strain of bacteria to different phages and observing if lysis occurs, phage typing can help identify and differentiate between different strains of bacteria. This method is often used in epidemiological studies and can provide valuable information about the genetic relatedness and potential sources of bacterial infections.

Serology is the correct answer because it refers to the identification of antibodies against specific microorganisms. Serology involves the detection and measurement of antibodies in the blood, serum, or other bodily fluids to determine if a person has been exposed to a particular microorganism or pathogen. This can be done through various techniques such as enzyme-linked immunosorbent assay (ELISA) or Western blotting. Serological tests are commonly used in diagnosing infectious diseases and monitoring immune responses to vaccines.

Bacterial sub-species are called strains. Strains refer to variations within a species that have distinct characteristics, such as differences in genetic makeup or behavior. This term is commonly used in microbiology to differentiate between different groups or populations of bacteria within a species.

Clostridium is a gram-positive rod-shaped bacterium. Gram-positive bacteria have a thick peptidoglycan layer in their cell wall, which retains the crystal violet stain during the Gram staining process, causing them to appear purple under a microscope. Rod-shaped bacteria, also known as bacilli, have a cylindrical shape. Clostridium species are anaerobic bacteria that can produce endospores, allowing them to survive in harsh conditions. They are commonly found in soil and the gastrointestinal tract of humans and animals. Clostridium species can cause various diseases, including tetanus, botulism, and gas gangrene.

Treponema pallidum is the correct answer because it is the bacterium responsible for causing syphilis, a sexually transmitted infection. Sarcina ventriculis, Spirillum minus, Bacillus megaterium, and Corynebacterium diphtheriae are not associated with syphilis.

Vibrio is a gram-negative curved rod bacterium. It is a genus of bacteria that includes several species, such as Vibrio cholerae, which causes cholera. Gram-negative bacteria have a thin peptidoglycan layer in their cell walls and do not retain the crystal violet stain used in the Gram staining technique. The curved rod shape is a characteristic feature of Vibrio bacteria, distinguishing them from other bacteria listed in the options.

PCR (Polymerase Chain Reaction) is a technique used to amplify DNA sequences. It involves the use of DNA primers, which are short pieces of DNA that bind to specific regions of the DNA sequence to be amplified. Taq polymerase, a heat-stable DNA polymerase, is used to extend the primers and synthesize new DNA strands. The repeated cycles of heating and cooling in PCR allow for the amplification of the DNA sequence, making it a powerful tool in molecular biology and genetic research.

Archaea are not wall-less, which means they do have a cell wall. The other options in the classification of prokaryotes are true. Gracilicutes have thin cell walls or gram-negative cell wall, Firmicutes have thick skin or gram-positive cell wall, Tenericutes have a pliable and soft nature or lack of rigid cell wall, and Mendosicutes lack conventional peptidoglycan.

Neisseria gonorrhoea is a diplococci. Diplococci are bacteria that occur in pairs and Neisseria gonorrhoea is a gram-negative bacterium that is responsible for the sexually transmitted infection gonorrhea. It is commonly found in pairs, with one bacterium appearing adjacent to the other, giving it a characteristic diplococci shape.

Chlamydia is a correct answer because it is an obligate intracellular parasite. Obligate intracellular parasites are microorganisms that can only survive and reproduce within the cells of a host organism. Chlamydia infects the cells of humans and animals, causing a variety of diseases such as chlamydia infection, which is a sexually transmitted infection. It relies on the host cell's machinery to replicate and spread, making it dependent on the host for survival. The other options, Clostridium, Stretococcus, Nocardia, and Campylobacter, are not obligate intracellular parasites.

Borellia is a spirochete because it is a genus of bacteria that possesses a unique spiral shape. Spirochetes are characterized by their long, helical, and flexible bodies, which allow them to move in a corkscrew-like motion. Borellia is known to cause Lyme disease, a tick-borne illness that affects humans and animals. Its spiral shape enables it to penetrate tissues easily and evade the host's immune system, making it a typical example of a spirochete.

Spirillum minus is the correct answer because it is the causative agent of rat bite fever. Rat bite fever is a bacterial infection that can be transmitted to humans through bites or scratches from infected rats. Spirillum minus is a spiral-shaped bacterium that is commonly found in the oral cavity and gastrointestinal tract of rats. It can cause a range of symptoms in humans, including fever, joint pain, and skin rash. Prompt treatment with antibiotics is necessary to prevent complications and further spread of the infection.

Clostridia is the correct answer because it is a gram positive bacteria that typically has a low percent G+C in its DNA base composition. This means that the DNA of Clostridia contains a lower percentage of guanine (G) and cytosine (C) nucleotides compared to adenine (A) and thymine (T) nucleotides. This characteristic is useful in identifying Clostridia in DNA base composition tests.

Nocardia is a type of acid-fast rod. Acid-fast rods are bacteria that retain a stain even after being treated with an acid alcohol solution. Nocardia is known for causing infections in humans, particularly in the lungs, skin, and brain. It is commonly found in soil and can be transmitted to humans through inhalation or direct contact. Other options such as Bacillus, Enterobacteria, Helicobacter, and Neisseria are not acid-fast rods and have different characteristics and roles in microbiology.

Enterobacteria is a gram-negative rod because it belongs to the family Enterobacteriaceae, which consists of gram-negative bacteria that are rod-shaped. These bacteria are commonly found in the intestines of humans and animals and can cause various infections, including gastrointestinal and urinary tract infections. Gram-negative bacteria have a thin peptidoglycan layer in their cell walls, which makes them appear pink or red when stained with a Gram stain.

Ribosomal RNA (rRNA) sequencing is a widely used method in molecular biology to study the genetic relationships between organisms. One of the advantages of rRNA sequencing is that all cells contain rRNA, making it a useful tool for studying diverse organisms. Additionally, closely related species have fewer differences in their rRNA sequences compared to distantly related species, allowing for more accurate comparisons. Another advantage is that rRNA sequencing does not require culturing the organism, which can be time-consuming and challenging. However, the given statement that rRNA genes are not highly conserved is false. In fact, rRNA genes are highly conserved across different species, making them a reliable target for sequencing and analysis.

Moraxella lacunata is a Diplobacillus because it is a bacterium that appears as pairs of rod-shaped cells. The term "diplo" means double, and "bacillus" refers to a rod-shaped bacterium. Therefore, Moraxella lacunata fits the description of a Diplobacillus. Bacillus anthracis, Bacillus meggaterium, Corynebacterium diphtheriae, and Vibrio cholera are not Diplobacilli because they do not exhibit the characteristic pairing of rod-shaped cells.