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Microbiology BIO 150 – Test 1 Study Guide with Verified
Questions & Answers | Northern Virginia Community College
(NVCC) | A+ Scored (2025)
What is the biological function of an endospore? Endospores are heat-resistant forms of bacteria, so it allows the bacteria to survive extreme conditions What are the three domains of life that all living organisms are separated into? Bacteria, Archaea, and Eucarya How do you write a scientific name? All in italics or underlined with the Genus FIRST LETTER capitalized and the species in lowercase. Many describe the microbe or honor the scientist Are archaea more closely related to bacteria or eukarya? Eukarya Who developed the 3 domain system? Carl Woese Who is Robert Hooke? First person to describe microbes Who is Anton Van Leewenhook? He was the first to describe bacteria from his own teeth What does the Theory of Spontaneous Generation say? organisms can arise spontaneously from non-living material Who disproved spontaneous generation and how? Louis Pasteur used swan-necked flasks that had a heated solution/broth. No microbes could get past the swan neck flask opening and into the solution. pasteaurization a process of high heat for a short time to kill harmful bacteria in beverages How did Louis Pasteur disprove spontaneous generation? In louis pasteur's experiment, Why was the neck S shaped? to trap the microbes in the air in the curved neck in louis pasteur's experiment, Why was the flask heated? to kill the microbes in the broth
in louis pasteur's experiment, Why was the flask tilted after a short time? To introduce the trapped bacteria Who is Robert Koch?
- noted for developing "Koch's Postulates"
- outlines the use of pure cultures to identify/determine the agent for infections/diseases
- father of medical microbiology Nobel Prize Winners Koch and Pasteur Koch's Postulates a sequence of experimental steps for directly relating a specific microbe to a specific disease.
- Draw blood- Dead rat & healthy rat Look under microscope Suspected pathogen spotted Must be present in all cases of disease
- Must be grown in pure culture (slice of potato) Lab cultures- colonies of suspected pathogen *Streaking isolates pathogen- pure culture
- Inoculate healthy animal with pathogen Does it kill rat?
- Suspected pathogen must be isolated and shown to be same as original
- Blood drawn from healthy dead rat and re isolated Pure culture must be the same Summarize Koch's postulates for linking specific microorganisms to certain diseases
- If you isolate the bacterial agent of a sick animal, you can infect a healthy individual with the same illness.
- The organism must always be present, in every case of the disease.
- The organism must be isolated from a host containing the disease and grown in pure culture.
- Samples of the organism taken from pure culture must cause the same disease when inoculated into a healthy, susceptible animal in the laboratory.
- The organism must be isolated from the inoculated animal and must be identified as the same original organism first isolated from the originally diseased host. Microbiome
- bacteria and archaea Characteristics of eukaryotes? Examples?
- single or multicelled
- true nucleus (membrane bound)
- membrane bound organelles
- larger, complex
- examples: algae, protozoa, fungi How do Archaea differ from Bacteria? How are they the same? differ-chemical composition of cell wall (archaea do not have peptidoglycan in cell wall) same-size, shape, appearance, movement, reproduction Viruses are not alive or cells, they are acellular Which type(s) of microorganisms are eukaryotic? Fungi, protozoa, Algae, Animal Parasites- Helminths How do you release energy one step at a time? Respiration and fermentation How do enzymes speed up reactions? By lowering the activation energy NAME 3 Ways to phosphorylate Substrate level phosphorylation , Photophosphorylation, Oxidative phosphorylation What is oxidative phosphorylation? Uses energy released by the electron transport chain to power ATP synthesis. After Glycolysis, Where do 2 pyruvates go to further oxidize? Krebs cycle Where do we get 2 pyruvates from in krebs cycle? Glycolysis What's the starting material for glycolosis? Glucose Where does substrate level phosphorylation occur? Krebs cycle and glycolysis
Where does oxidative phosphorylation occur? electron transport chain How was ATP creating in glycolysis? Substrate level phosphorylation What is respiration? Glucose is oxidized to get ATP
- Glycolysis
- Krebs cycle
- Electron transport Chain System Catabolism breaks down complex molecules Anabolism uses energy to build up complex molecules What is fermentation? Glycolysis & Pathway (alcohol/acid) IN FERMENTATION how many ATPS Total from glucose? NET: 2 ATPs IN GLYCOLYSIS, HOW MANY ATPs net for one glucose? 2 ATP iN GLYCOLYSIS,besides ATP - What else do you generate? 2 NADH iN GLYCOLYSIS,What is final sub compound? 2 Pyruvates How is ATP GENERATED (what phosphorylation method)DURING KREBS CYCLE? Substrate level phosphorylation What happens when you pass the electrons down the chain? Charged Membrane How do you charge the membrane? Pump the protons out of the cell Who is the final electron acceptor in fermentation?
How are endospores useful to a bacterial cell? Outline the endospore formation process Resting cells found in certain bacterial species. Resistant to desiccation, heat and chemicals Can be viable for centuries Sporulation: process of endospore formulation. NOT REPRODUCTION 1.) Spore septum begins to isolate newly replicated DNA and a small portion of cytoplasm 2.) Plasma Membrane starts to surround DNA, cytoplasm and membrane isolated in step 1 3.) Spore septum surrounds isolated portion, forming forespore 4.) Peptidoglycan layer forms between membranes 5.) Spore coat forms 6.) Endospore is freed from cell Spontaneous Generation Theory the theory that living organisms can rise from nonliving things Characteristics of Microorganisms 1.) Microbes as a group show diversity, multiple domains 2.) Microbes are Ubiquitous! They're everywhere 3.) Structure=Function What is the importance of Microbial Life on earth? 1.) Major part of food chain of all organisms 2.) Waste breakdown/nitrogen cycling in plants 3.) Food Production 4.) Drug Production Beneficial Uses of Microbes 1.) Microbial Ecology 2.) Bioremediation 3.) Pest Control 4.) Biotechnology What are the three domains of life and who developed it? Bacteria, Archaea, Eukarya. Developed by Dr. Carl Woese What characteristics are used to classify life into three domains?
Ribosomal RNA, Single Cell/multicellular, Transferral RNA Structure Prokaryote Bacteria 1.) Single-Celled Organisms 2.) Bacteria exist in different shape, have cell wall made of Peptidoglycan 3.) Asexual Reproduction, Binary Fission 4.) motile or Non-motile, Flagella allows it to move Prokaryote Archaea 1.) Present in most extreme environments 2.) Methanogens, high methane environment 3.) Extreme Halophiles, high salt environment 4.) No Peptidoglycan, different cell wall Fungi 1.) Multicellular or Unicellular 2.) Most engage in sexual reproduction, some in asexual reproduction and some can do both 3.) Mycellea made up of filaments called Hyphae 4.) Cell wall made of Kiatin 5.) Absorb organic chemicals for nutrients Protozoa 1.) Unicellular 2.) Free living or parasitic 3.) Some are Photosynthetic 4.) sexual or asexual reproduction 5.) May be Modal, can use flagella, massive Cillia or a pseudopod "false foot" to move in environment 6.) Disease causing agents Algae 1.) Water Plants 2.) Cellulose Cell walls 3.) Uni or multicellular forms Helminths 1.) Parasitic flatworm/roundworm
Biofilm A surface-coating colony of one or more species of prokaryotes that engage in metabolic cooperation. normal human microbiota Populations of mutualistic and commensal microbes that live on and in the bodies of healthy individuals, about 100 trillion bacteria in total, representing hundreds of species emerging infectious diseases A new disease or one that reemerges, coronavirus Primary Differences between Prokaryote and Eukaryote cells 1.) Prokaryotes are smallest organisms/unicellular with circular DNA in nucleoid region, Eukaryotes are larger and multicellular, have enclosed nucleus with strands of DNA 2.) Prokaryotes have cell wall for structure/protection, Eukaryotes have cytoskeleton for support 3.) Prokaryotes do Asexual Reproduction(Binary Fission), Eukaryotes do Sexual Reproduction Baccillus Cell Shape(Rods) SingleBaccillus- Single rod Diplobaccillus- Two rods Streptobaccillus- Chain of rods Coccobaccillus-rounded rod, square shape Coccus Cell Shape (Round/spherical) Diplococci- Two cocci, one plane of division Streptococci-Chain of cocci, one plane of division Tetrad- Four cocci in a quad, two planes of division Sarcinae- Two tetrads stacked Staphylococci- Clump of Cocci, looks like grapes How do Prokayotic and Eukaryotic Flagella movement differ? Prokaryotic flagella rotate to allow them to run and tumble. Eukaryotic flagella are composed of microtubules in a 9 pairs + 2 array that allow it to bend and grappling hook twitching motility Describe function of bacterial cell wall Made of Peptidoglycan, sugar protein cell wall Combats lysis, osmotic lysis Provides strength to resist rupturing due to osmotic pressure good antibiotic target
Explain the gram stain procedure 1.) Primary stain of crystal violet 2.) Use mordant of Iodine to allow for primary stain to stick. Intensifies the affinity of a stain to a structure 3.) Decolorizing agent of Alcohol-Acetone, determines whether gram pos or neg. Dehydrates the cell and pores in cell wall will seal. Will seal the mordant and primary stain. Gram pos cells stay purple while gram neg cells turn colorless. 4.) Counterstain of Safranin. Will turn the gram neg bacteria from colorless to red. However gram pos cells will stay purple even with counterstain. Describe the Structure of the Plasma Membrane and its components Plasma membrane contains a phospholipid bilayer, peripheral proteins, and Integral and Transmembrane proteins penetrate the membrane selectively permeability and what are some processes that move materials across the plasma membrane a property of cell membranes that allows some substances to pass through, while others cannot Simple diffusion through the lipid bilayer Facilitated diffusion through a nonspecific transporter Facilitated diffusion through a specific transporter Osmosis through the lipid bilayer and an aquaporin Osmosis Osmosis is the movement of water particles through a semipermeable membrane going from a high to low concentration until equilibrium is reached on both sides. Describe the structure of bacterial ribosomes. Prokayotes: 70s 50s+30s subunits, 30s is the small subunit and 50s is the large subunit. Together they make the complete 70s ribosome unbound in bacterial cells Eukaryotes: 80s 40s+60s subunits. 40s is the small subunit and 60s is the large subunit. Together they make the complete 80s subunit Membrane bound: Attached to ER and free in cytoplasm Microbial Growth an increase in number of cells/population, not in cell size Effects of temperature
Define Phylogeny. evolutionary history of an organisms (classification and relationships) State Carl Woese's observation and his contribution to modern classification Greater the rRNA gene variation between organisms, greater is the divergence in the evolutionary tree. He discovered Archaea and rRNA Classification Binomial nomenclature: write the scientific name in proper format recognizing the genus and species in a scientific name Define Autotrophs and Heterotrophs Autotrophs use Carbon Dioxide as Nutrition Source Heterotrophs use Complex organix compounds Define aerobes anaerobes,Aerobes use O2, can break it down Anaerobes can live w/out o2, What is known in ELISA test Known antibodies- sandwich— urine - tag label- enzyme- color causing substrate- done in wells What is known in Western blot? Identifies antibodies- known proteins in serum- binds - lyme disease Which essay identifies unknown antibodies in pts SERUM? Western blot Southern blot identifies microorganisms using DNA probes - fishing - DNA in gel Nucleic Acid Hybridization The ability of Dna strands from one organism to hybridize with DNA strands of another organism DNA fingerprinting analysis of fragments of DNA as a form of identification DNA sequencing Determining the exact order of the base pairs in a segment of DNA.- DNA base composition GC% morphological What shape? size? arrangement? Cell wall? differential staining
Gram staining, acid-fast staining. What is the benefit of staining? improves contrast Biochemical tests are used to determine enzymatic activities ... Do you respire? Do you use Lactose? Do you ferment? Staph means Clusters (Think "staff" in an office gather in clusters!) Strep- means what? chain if you were to gram stain bacteria with thick cell wall, what color would it be? gram positive bacteria- violet if you were to gram stain bacteria with thin cell wall, what color would it be? gram negative- red acid fast stain A staining procedure for identifying bacteria that have a waxy cell wall. uses alcohol and steam. mycolic acid if you have done an acid fast test and the organism stains blue, is it acid fast positive or negative? methyl blue= negative if you have done an acid fast test and the organism stains red, is it acid fast positive or negative? carbol fuchsin- red Prokaryotic cell membrane highly selective permeability passive processes simple diffusion, facilitated diffusion, osmosis active processes energy (ATP) required (active transport- transporter protein) group translocation requires a transporter protein and (PEP)(PHOSPHOENOLPYRUVIC ACID) ; substance is altered as it crosses the membrane prokaryotic ribosomes 70S (30S and 50S) smaller than eukaryotic ribosomes
