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Questions and Answers
What is the main origin of tertiary cell cultures?
What is the main origin of tertiary cell cultures?
What cellular process is involved in the penetration of a virus into a host cell?
What cellular process is involved in the penetration of a virus into a host cell?
Which step of viral replication involves the removal of the viral capsid?
Which step of viral replication involves the removal of the viral capsid?
What type of organisms do fungi belong to?
What type of organisms do fungi belong to?
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How are naked viruses typically released from the host cell?
How are naked viruses typically released from the host cell?
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Which type of fungi primarily decompose plant material in soil and water?
Which type of fungi primarily decompose plant material in soil and water?
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Where do most DNA viruses assemble within the host cell?
Where do most DNA viruses assemble within the host cell?
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What characteristic do all fungi share regarding their nutritional needs?
What characteristic do all fungi share regarding their nutritional needs?
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What was the main criterion used to distinguish the plant kingdom from the animal kingdom?
What was the main criterion used to distinguish the plant kingdom from the animal kingdom?
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Which type of organism is NOT included in the kingdom Protista?
Which type of organism is NOT included in the kingdom Protista?
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Which of the following is a characteristic unique to eukaryotic cells?
Which of the following is a characteristic unique to eukaryotic cells?
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What energy source do members of the plant kingdom primarily utilize?
What energy source do members of the plant kingdom primarily utilize?
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Which of these statements about microorganisms is NOT true?
Which of these statements about microorganisms is NOT true?
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Which protist is characterized by containing chlorophyll?
Which protist is characterized by containing chlorophyll?
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Which of these organisms share features with both fungi and protozoa?
Which of these organisms share features with both fungi and protozoa?
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What was a significant result of the introduction of the electron microscope?
What was a significant result of the introduction of the electron microscope?
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What does the tRNA molecule specifically bind to during protein synthesis?
What does the tRNA molecule specifically bind to during protein synthesis?
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Which of the following statements is true regarding ribosomal RNA (rRNA)?
Which of the following statements is true regarding ribosomal RNA (rRNA)?
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What is the primary role of the promoter in a gene?
What is the primary role of the promoter in a gene?
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In eukaryotes, what distinguishes exons from introns?
In eukaryotes, what distinguishes exons from introns?
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What defines the template strand of DNA?
What defines the template strand of DNA?
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What characterizes obligate aerobes in terms of oxygen requirement?
What characterizes obligate aerobes in terms of oxygen requirement?
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Which enzyme is absent in obligate anaerobes that contributes to the accumulation of hydrogen peroxide in the presence of oxygen?
Which enzyme is absent in obligate anaerobes that contributes to the accumulation of hydrogen peroxide in the presence of oxygen?
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How do facultative anaerobes adapt their metabolism?
How do facultative anaerobes adapt their metabolism?
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What is the primary condition that microaerophiles require for growth?
What is the primary condition that microaerophiles require for growth?
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Which of these minerals is crucial for the synthesis of cytochromes?
Which of these minerals is crucial for the synthesis of cytochromes?
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Which heavy metal ions are specifically required for various enzymatic reactions?
Which heavy metal ions are specifically required for various enzymatic reactions?
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What happens to microaerophilic organisms in high oxygen tension conditions?
What happens to microaerophilic organisms in high oxygen tension conditions?
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What role does sulfur play in cellular processes?
What role does sulfur play in cellular processes?
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What is the function of conidiophores in fungi?
What is the function of conidiophores in fungi?
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Which class of fungi is characterized by having no known sexual process?
Which class of fungi is characterized by having no known sexual process?
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What structure is responsible for the formation of basidiospores?
What structure is responsible for the formation of basidiospores?
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Which of the following is an example of a dimorphic fungus?
Which of the following is an example of a dimorphic fungus?
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What characteristic defines slime moulds during their life cycle?
What characteristic defines slime moulds during their life cycle?
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Which type of asexual spores are characterized by being formed from segments of a septated mycelium?
Which type of asexual spores are characterized by being formed from segments of a septated mycelium?
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What is the primary advantage of dimorphism in fungi?
What is the primary advantage of dimorphism in fungi?
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Which type of fungal spores are borne inside a sac and are formed on aerial hyphae?
Which type of fungal spores are borne inside a sac and are formed on aerial hyphae?
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What is the primary function of oxidative phosphorylation?
What is the primary function of oxidative phosphorylation?
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Which statements accurately describe photophosphorylation?
Which statements accurately describe photophosphorylation?
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What role do coenzymes such as NAD and FAD play in metabolic reactions?
What role do coenzymes such as NAD and FAD play in metabolic reactions?
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Which of the following processes conserves free energy from the oxidation of organic molecules?
Which of the following processes conserves free energy from the oxidation of organic molecules?
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What is the estimated amount of ATP synthesized from the oxidation of 1 mole of glucose to CO2 and water?
What is the estimated amount of ATP synthesized from the oxidation of 1 mole of glucose to CO2 and water?
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Which of the following best describes chemoorganotrophic metabolism?
Which of the following best describes chemoorganotrophic metabolism?
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During ATP synthesis, which of the following statements is true?
During ATP synthesis, which of the following statements is true?
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What is the significance of the free energy released during electron transport?
What is the significance of the free energy released during electron transport?
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Study Notes
General Microbiology & Immunology Notes (Part I)
- Microbiology is the study of minute or small organisms not visible to the naked eye.
- Antonie van Leeuwenhoek, known as the "Father of Microbiology", was the first person to observe microorganisms using a simple microscope.
- He observed small swimming organisms in pond water, calling them "animalcules."
- The theory of spontaneous generation (abiogenesis) proposed that life arose from non-living matter.
- Francesco Redi challenged this theory by demonstrating that maggots on decaying meat came from fly eggs, not the meat itself.
- Lazzaro Spallanzani further challenged spontaneous generation by showing that sealed and boiled flasks did not develop microorganisms, suggesting that air carried germs.
- John Needham, however, countered Spallanzani's experiment by stating that vital force was required.
- Louis Pasteur definitively disproved spontaneous generation by demonstrating that broth in swan-necked flasks remained sterile, even though exposed to air.
- He developed the process of pasteurization to prevent spoilage in liquids.
- Edward Jenner pioneered the concept of vaccination by demonstrating that cowpox infection provides immunity to smallpox.
- Robert Koch established postulates for establishing a link between a microorganism and a specific disease. These include proving the microorganism is present in every case of the disease; isolating and culturing the microbe; re-introducing the isolated microorganism into a healthy animal to cause the disease; and isolating the microorganism again from this diseased animal to show its identity.
- Koch also developed culture media and techniques for isolating and cultivating microbes, and identified many pathogens.
- Koch's laboratory helped make significant advancements in microbiology with discoveries like the petri dish, the use of agar, and the gram stain.
- Julius Petri developed the Petri dish.
- Frau Hesse introduced agar.
- Christian Gram developed the Gram stain.
- Paul Ehrlich pioneered chemotherapy using arsphenamine, a 'magic bullet' for treating certain infections.
- Joseph Lister introduced antiseptic surgery by using phenol.
Development of Microbiology
- Before the discovery of microorganisms, all living organisms were classified into two kingdoms: Animalia and Plantae.
- Criteria differentiating plant and animal kingdoms included energy source (light vs. oxidation), presence of chlorophyll, principal reserve materials (starch vs. glycogen), active movement, and cell wall.
- The kingdom Protista was proposed by Haeckel in 1866
- This kingdom comprised unicellular and multicellular organisms that lacked specialization/differentiation of cell types and tissues.
- The kingdom Protista was later modified to include only eukaryotic organisms like algae/chlorophyll containing protists.
- Protozoa were grouped as non-photosynthetic heterotrophic, unicellular eukaryotes.
- Fungi are non-photosynthetic eukaryotes with cell walls.
- Slime molds share features with fungi and protozoa.
- A major taxonomy differentiation occurred with three kingdoms. Eubacteria, Archaea and Eucarya.
Classification of Living Organisms
- Currently, a system of classification using three domains has become prevalent
- Domain Protista includes unicellular eukaryotes like algae. Protozoa, fungi, algae and bacteria were all categorized under this kingdom for a time
Viruses
- Viruses are submicroscopic infectious agents, made of genetic material (DNA or RNA) surrounded by a protein coat (capsid).
- They are obligate intracellular parasites, replicating only inside living cells.
- Viruses can have icosahedral, helical, or complex symmetry.
- Viral cultivation methods include tissue cultures (primary and secondary) and animal inoculation. Steps in viral replication include; attachment, penetration, uncoating, replication, assembly, and release.
Fungi
- Fungi are non-photosynthetic eukaryotic organisms that are heterotrophic, requiring organic compounds for energy and carbon.
- They are commonly aerobic or facultatively anaerobic saprophytes, and frequently decompose plant material.
- Fungi form a mass of branching filaments called hyphae, which together form a mycelium in some fungi.
- Yeasts are unicellular fungi that reproduce by budding.
Protozoa
- Protozoa are unicellular, non-photosynthetic, chemoheterotrophic eukaryotes lacking cell walls.
- They move by cilia or pseudopods and reproduce asexually or sexually.
- Different groups of protozoa including the sarcodina, ciliophora, mastigophora and sporozoa
Bacteria
- Bacteria are a diverse group of prokaryotic microscopic organisms.
- They inhabit various environments and play essential ecological roles (e.g., nutrient recycling).
- Bacteria have a cell wall containing peptidoglycan (except for mycoplasmas).
- Bacteria reproduce by binary fission, except for actinomycetes, which form conidiospores.
- They have three fundamental forms: spherical (coccus), rod-shaped (bacillus), and curved/spiral (vibrio, spirillum, spirochaete)
Bacterial Cell Structure
- A typical bacterium has a cell wall, cell membrane and cytoplasm containing ribosomes, genetic material and other cytoplasmic components like slime layer or capsule.
- Some types of bacteria have dormant spores under adverse environmental conditions.
- The nucleoid carries the cell’s genetic information as a single circular DNA molecule.
- The cytoplasm is an aqueous mixture containing nutrients, metabolites, waste products, enzymes, and reserve food.
- The cell membrane functions in selective permeability, transport, excretion, and biosynthesis. Note: Additional information in the text, like sections on the cell wall, bacterial morphology, special types of bacteria and/or other structural components, are not included in this summary.
Bacterial Metabolism
- Metabolism involves anabolism (building complex molecules) and catabolism (breaking down complex molecules).
- Organisms may obtain their energy via phototrophy (light), or chemotrophy (chemical reactions using organic or inorganic molecules). Different types of chemotrophs exist.
- Most eukaryotic cells and bacteria carry out chemoorganotrophic metabolism by the oxidation of organic molecules.
- The oxidation of organic molecules produces ATP via various pathways such as substrate-level phosphorylation and oxidative phosphorylation.
- Oxygen, nitrate, or other inorganic molecules may serve as the final electron acceptors during respiration.
- When oxygen is not available or when the organism cannot use respiration (e.g., in some bacteria), fermentation occurs.
Nucleic Acids/DNA
- Nucleic acids (DNA and RNA) carry genetic material.
- DNA has a double helix structure with four bases (adenine, guanine, cytosine, and thymine).
- RNA has a single-stranded structure with four bases (adenine, guanine, cytosine, and uracil).
DNA Replication
- DNA replication is semi-conservative; each new DNA molecule contains one original strand and one new strand
- It typically occurs from a specific origin of replication and proceeds bidirectionally; Replication is typically bi-directional.
- DNA polymerases are involved in copying the DNA
- Two growing strands are involved, one leading and the other lagging; DNA nucleotides are added to the 3' end of a growing DNA chain.
Transcription and Prokaryotic Gene Expression
- Transcription is the synthesis of RNA using DNA as a template. This process involves three stages - initiation, elongation, and termination.
- Prokaryotic organisms have only one RNA polymerase consisting of multiple subunits.
- Gene expression is regulated with constitutive enzymes present at relatively constant levels and induced enzymes produced only when substrates are present.
Translation
- Translation is the synthesis of proteins using mRNA as a template. It follows three steps - Initiation, Elongation, and Termination
- Ribosomes that are composed of RNA and protein are essential for this process
Regulation of Gene Expression
- Regulation of gene expression controls the levels of proteins being produced.
- Mechanisms include; induction (an increase in enzyme level) with an inducer; end product repression (decrease in enzyme level) by the effect of an end product) as well as feedback inhibition (the end product of the pathway inhibits the first enzyme)
- Genes and operons are controlled with regulatory proteins.
Bacterial Growth and Growth Curve
- Some prokaryotes grow using a closed system, where the medium and growth is contained in a batch culture.
- In a batch culture, bacterial growth is best characterized by four phases: the lag phase, log phase, stationary phase, and death phase.
- An open system, like a continuous culture system, is a more controllable method for measuring cell growth.
Microbial Variation
- Variation in microorganisms is an important aspect of adaptation and evolution
- Genotype or phenotype changes can be reversible or irreversible.
- Mutation is a permanent change in the genetic material (DNA)
- Environmental factors, like radiation or chemicals, can induce mutations.
- Organisms have repair mechanisms to fix DNA damage
Microbial Control,
- A variety of methods are used to control microorganisms in various environments.
Genetic Transfer
- Genes can be transferred vertically (from parent to offspring) or horizontally (among different organisms).
- Horizontal gene transfer (HGT) in microorganisms occurs through transformation, conjugation, and transduction.
Microbial Growth and Measurement
- Microbial growth is measured using various methods, including; observing cell mass (dry weight or optical density); and viable cell counts (based on the number of live cells).
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Description
Explore the foundational concepts of microbiology and immunology in this quiz. Learn about key figures such as Antonie van Leeuwenhoek and Louis Pasteur, as well as important theories like spontaneous generation. This quiz will test your understanding of the early discoveries that shaped the field of microbiology.
